408 Stroker Build Suggestions

[MobileCustoms]

We built a 408 for my brother in law, for his 68 Dart
Scat rotating assy with dished pistons pump gas friendly 10.2 to 1
RHS iron heads and 20 year old Hughes cam .565 lift, M1 intake and a quick fuel 850, 904 Trans
Engine runs great lot of low end power and runs out nice to 6500 rpms.

Car runs 11.10 on a warm day, cooler day 11.00, and i believe next year in the winter it will go 10.80s, having the right combo is very important.

View attachment 1715220700

Watching this thread closely, as I am building a stroker also. Should be finishing up most of the assembly of the shortblock tonight! Can't wait to see what it does. I'm hoping for numbers close to what you posted.

 

[zsn0w]

OP;This is spot on, so IMO your stroker with stock 308s, might best a 367 with Eddies in the HP war, but it sure won't be by much.
Here's a poser for those in the know (not me);
Op is looking for bottom end, so Compare;
a 408 with a 228/232/110 cam,unported 308 iron heads, and the Scr adjusted to yield 160psi;
to a 367 at 10.6Scr and ~175psi with OOTB Eddies.
I set the ICA to 65*, and the elevation to 450ft.
But wait, where does "bottom-end" start?
Let's say the stroker might be good for a 2500 and 3.23s, and
the 367 might like a 2800 and 3.55s.
Lets say the stroker makes 220ftlbs at 2500, and with 3.23s, and a 2.45 low, is laying down 1741 ftlbs, on the start line.
Lets say the 367 makes only 200 at 2800, and with 3.55s is laying down 1739.5 ftlbs.
See what I mean?
I'm just guessing at the numbers. It doesn't matter what the actual numbers are so long as the 10% split remains the same. eg if the stroker made 300 and the 367 made 272, it would still net the same result. So the only penalty is that the 367 cruises at 10% more hiway rpm.
In any case,1740ftlbs is way more torque than you need to break loose a pair of say 275/60-15 street tires. and Neither one of these combos is gonna be able to use WOT in first gear, below 35/40mph, without breaking the tires loose.
Now that was just two targets, namely off the line and cruising.
What about 3.23s versus 3.55s at lower speeds?
Well 3.23s will get you 60mph ~ 6000rpm at the top of first, for the stroker,so she is long past prime with the 308s and the 2832, so you'll wanna shift at say 5400, and that drops the Rs to 3200@54mph
3.55s will be 60~6600 for the 367, also in first, so some people might want to shift earlier but with the Eddies on there now and 1.6 arms, I say ride it out,lol; I always did. But say you wanna be fair. Well, the new shift rpm with the Eddies might be 5800, so that would be into second at 53mph@3420 Rs. Ok but if there is less than a 10% torque difference at those rpms,between these two engines, at the road; than the 367 could pull ahead.... see what I'm saying?
It's not always about cubes........ It's the whole combo

Plus the stroker will come in at around 10.5 Scr with 17cc cups,and 63cc chambers;and so about 170psi with that 2832 cam so you are gonna have to get rid of some of that pressure in order to be able to run pump gas...... and that is gonna be extra cost. Either the pistons will have to be scooped out, or a thicker head gasket used, which will mess up your Q; and so then you need a reverse dome piston, or an open-chamber head,and forget Quench .
Whereas the thrown together 367 with the same 63cc but aluminums now, is likely to run 175 psi with the same cam..... no extra machining, and has almost ideal Q of .040..
But yeah the stroker will make more dyno torque than the 367, I can't argue that. The thing is what can you do with it? The 367 already has more torque than the chassis, and the biggest tires you can fit in any stock A-body tubs,can handle, without a traction aider. So unless you wanna tow a 5th wheel trailer.......... that extra torque is all gonna go up in tiresmoke.

Now before you think I'm pushing 367 on you, I'm not. I'm simply offering an alternative to fit into your budget.

The thing that concerns me is how much is it gonna cost to get your compression LOW ENOUGH to run a 2832 and 308s. You add that onto the cost of the stroker kit; then compare that total to the installed and ready to go aluminum heads of your choice.
Don't forget to factor in the cost of gears and the TC, and the Trans will need some upgrades to live behind the stroker.
If you already own 3.23s and a 2500TC, and a beefed up trans;well then stroker is a no-brainer. But if you already own 3.55s and 2800 to 3000, then maybe the 367 is.
And then there is the long-term fuel costs. The aluminum headed-367 will burn 87E10 no problem. Even up to 185psi. What will you have to burn in the iron headed stroker at 160psi? This could add up to thousands of dollars over the life of the engine. My aluminum heads paid for themselves years and years ago.

BTW, you will need different pushrod ends with adjustable arms.

I appreciate all the info. I should've probably made a few things clearer in my initial post here. My car is actually a b-body, but I know a lot of people here have a ton of experience with engines, so I posted it on both forums. Also, it will be a manual car. Right now it's got a 3 speed on the floor. That will be changing to an OD 4 speed A833 eventually. Should'e definitely included all of that in my original post.
One of the reasons I had decided to go with the 408 instead of a 367 is due to the cost of dropping in new pistons after boring in the cylinders and getting the crankshaft refinished. When taking all of that cost into account, I felt like the extra money to go up to a 408 was worth it for the extra inches, because it will give me room to grow should I decide to up the HP in the future. The 308s are also basically out at this point. There was a chance I'd throw the stock irons back on the bottom end to get it running until I could afford the edelbrock heads, but that's almost definitely not happening now after the advice I've received. I'd rather do it right than do it quickly at this point. The posts from you and everyone else here have made it very clear to me that the iron heads, even 308s, are a bad idea. I have a running 318 in my car right now, so I am fine having to spend some more time saving up to get the right parts rather than the cheap parts. Although, I'd still like it to be as budget friendly as possible besides, so thanks for keeping that in mind so much with your suggestions. Kind of hypocritical on my end, I know. Part of what I'm trying to get a feel for here is where it is worth it to spend the money and where it is okay to go a little cheaper. You've all convinced me that the heads are definitely worth the money, regardless of displacement I choose.
What are your thoughts on the 408 with the aluminum heads then? A lot of what I've been considering with this build since reading everyone's suggestions is upgrading over time. I'm planning on building the bottom end first, then saving up for some aluminum heads and throwing them on there with what stock components I can use and upgrading as money comes in. If that's not possible, I won't do it. I don't want to risk something blowing up the whole engine on me because I got too impatient to wait until I had enough money for better rockers. Just trying to feel out my options so I can have a running engine sooner(relatively). If I haven't shown my lack of knowledge on pushrod engines yet, I hope it's pretty apparent now, haha. Thanks for all your input and suggestions, it's all super helpful no matter what direction I decide to go in with this engine.

 

[autoxcuda]

OP;This is spot on, so IMO your stroker with stock 308s, might best a 367 with Eddies in the HP war, but it sure won't be by much.
Here's a poser for those in the know (not me);
Op is looking for bottom end, so Compare;
a 408 with a 228/232/110 cam,unported 308 iron heads, and the Scr adjusted to yield 160psi;
to a 367 at 10.6Scr and ~175psi with OOTB Eddies.
I set the ICA to 65*, and the elevation to 450ft.
But wait, where does "bottom-end" start?
Let's say the stroker might be good for a 2500 and 3.23s, and
the 367 might like a 2800 and 3.55s.
Lets say the stroker makes 220ftlbs at 2500, and with 3.23s, and a 2.45 low, is laying down 1741 ftlbs, on the start line.
Lets say the 367 makes only 200 at 2800, and with 3.55s is laying down 1739.5 ftlbs.
See what I mean?
I'm just guessing at the numbers. It doesn't matter what the actual numbers are so long as the 10% split remains the same. eg if the stroker made 300 and the 367 made 272, it would still net the same result. So the only penalty is that the 367 cruises at 10% more hiway rpm.
In any case,1740ftlbs is way more torque than you need to break loose a pair of say 275/60-15 street tires. and Neither one of these combos is gonna be able to use WOT in first gear, below 35/40mph, without breaking the tires loose.
Now that was just two targets, namely off the line and cruising.
What about 3.23s versus 3.55s at lower speeds?
Well 3.23s will get you 60mph ~ 6000rpm at the top of first, for the stroker,so she is long past prime with the 308s and the 2832, so you'll wanna shift at say 5400, and that drops the Rs to 3200@54mph
3.55s will be 60~6600 for the 367, also in first, so some people might want to shift earlier but with the Eddies on there now and 1.6 arms, I say ride it out,lol; I always did. But say you wanna be fair. Well, the new shift rpm with the Eddies might be 5800, so that would be into second at 53mph@3420 Rs. Ok but if there is less than a 10% torque difference at those rpms,between these two engines, at the road; than the 367 could pull ahead.... see what I'm saying?
It's not always about cubes........ It's the whole combo

Plus the stroker will come in at around 10.5 Scr with 17cc cups,and 63cc chambers;and so about 170psi with that 2832 cam so you are gonna have to get rid of some of that pressure in order to be able to run pump gas...... and that is gonna be extra cost. Either the pistons will have to be scooped out, or a thicker head gasket used, which will mess up your Q; and so then you need a reverse dome piston, or an open-chamber head,and forget Quench .
Whereas the thrown together 367 with the same 63cc but aluminums now, is likely to run 175 psi with the same cam..... no extra machining, and has almost ideal Q of .040..
But yeah the stroker will make more dyno torque than the 367, I can't argue that. The thing is what can you do with it? The 367 already has more torque than the chassis, and the biggest tires you can fit in any stock A-body tubs,can handle, without a traction aider. So unless you wanna tow a 5th wheel trailer.......... that extra torque is all gonna go up in tiresmoke.

Now before you think I'm pushing 367 on you, I'm not. I'm simply offering an alternative to fit into your budget.

The thing that concerns me is how much is it gonna cost to get your compression LOW ENOUGH to run a 2832 and 308s. You add that onto the cost of the stroker kit; then compare that total to the installed and ready to go aluminum heads of your choice.
Don't forget to factor in the cost of gears and the TC, and the Trans will need some upgrades to live behind the stroker.
If you already own 3.23s and a 2500TC, and a beefed up trans;well then stroker is a no-brainer. But if you already own 3.55s and 2800 to 3000, then maybe the 367 is.
And then there is the long-term fuel costs. The aluminum headed-367 will burn 87E10 no problem. Even up to 185psi. What will you have to burn in the iron headed stroker at 160psi? This could add up to thousands of dollars over the life of the engine. My aluminum heads paid for themselves years and years ago.

BTW, you will need different pushrod ends with adjustable arms.

If the -17cc dish pistons put you at 10.5:1, I must be running the -22cc dish pistons.

For what zsn0w is looking for, I think 9.5-9.7:1 compression is a safer bet.

 

[AJ/FormS]

Well that changes everything, lol. Not the B-body per se, but more importantly,that A833 overdrive.Between that and the chitcanned 308s, you are on the right track.... and you have already received a lotta good advice earlier.
So then with the .73 overdrive, you can run almost any rear gear that you might fancy. However, with a 2832 cam, it will be easy to go overboard. The ratios in that box are 3.09-1.67-1.00-.73od . Anything more than about a 11/1 starter gear will be kindof crazy with a 408; 3.09x3.91= 12.08. This is more than adequate even with 28"tires in the heaviest of Bs.
The problems come in second and third. The splits are .54 and .60. So if you shift at 5500, then the Rs will drop to those percents, namely 2970 and 3300. My 367 didn't really go for that, but your stroker is the ideal solution, especially with keeping the cam so smal (2832). Another thing that happens with that box, is because the splits are so broad, the cruise rpm gets to be pretty slow and not all cams like that. For 3.91s and 28s,the cruise is 65=2226, which again will work nicely with the 2832 cam.
The real problem is around town. Still with 3.91s and 28s;30 mph will be 2350 in second,4350 in first. A 367 does not have enough torque at 2350 to accelerate briskly, so that forces a downshift. But 4350 is buzzing pretty good, So it works...sorta, for a non-stroker. Of course at 4350 and WOT, the stroker will just explode in tiresmoke. So lets bring back that 1850 to soften the hit, lol.
Third gear will kindof be a rarely used gear, being primarily a stepping stone to cruising. Third will get you 65@3050, then into OD. Second will get you 36@2800 a good cruising rpm.
Now for a huge warning;
I broke two of those overdrive gears with a 318. So when you go into "4th", make sure the power is off. A 318LA was rated at something like 340ftlbs at 2400. Even with headers and a TQ I doubt mine made much more than that, so, you are gonna have to learn to take it easy on overdrive, especially going into it. At your cruise rpm of 2226 she'll be fine, as long as you remember to back off the throttle coming out of third. That's how I exploded both of mine. Nevertheless get yourself a spare. I bought them at swapmeets for average cost of $100 apiece.

So again, I think you are on the right track now, and obviously I was waaaaay off base, My apologies.

And getting the cylinder pressure DOWN,while maintaining a good Q, is gonna be your biggest hurdle.

 

[rumblefish360]

Yeah, I was figuring I'd go with 1.6 since a lot of the cams I was looking at would be around .55 with a 1.6, and the flow numbers I've seen on the edelbrock heads have it flowing higher up until around .6 or higher. I'm understanding this correctly, right? @autoxcuda was recommending the .515 lift due to the budget aspect of my build so that I could use stock rockers, I believe? But, if I bought 1.6 ratio rockers, would they need to be adjustable with a hydralic flat tappet cam? Or one of the pushrods or the rockers would need to be adjustable to make it work? Pushrods and rocker arms are the pretty much the things I understand the least, being much more used to OHC engines.

1st question, yes.
2nd question, yes.
3rd question, the rockers, they only come adjustable and can be used on any cam tappet style
4th question, the adjustable point is at the rocker. You don’t need to use an adjustable pushrod

You’ll gain a little lift. Not worth the $500 for comp roller rockers and another $125+ push rods. Factory iron adjustable rockers are 1.46. Rocker Arm Specialities can correct them, but that cost, initial cost, and shipping i’d guess at $300+ total.

I don’t think I’d bother with adj rockers and pushrods until you go to a bigger cam...OR just do all that now and spend money now.

I suggested stamped rockers worried that would take you $650 over budget. And suggested the smaller cam to go with that.

I must have missed the $650 budget and the posters future build NOT including ported heads later on.
My bad.....

Here I have to agree with autoxcuda.

Don’t mind AJ, he likes to bally-ho more garbage into run on sentences that rain on your parade just to chest pound his 367 as the ultimate engine while downing yours as a waste of time and garbage not worth ****.

Carry on AJ!

 

[autoxcuda]

1st question, yes.
2nd question, yes.
3rd question, the rockers, they only come adjustable and can be used on any cam tappet style
4th question, the adjustable point is at the rocker. You don’t need to use an adjustable pushrod



I must have missed the $650 budget and the posters future build NOT including ported heads later on.
My bad.....

Here I have to agree with autoxcuda.

Don’t mind AJ, he likes to bally-ho more garbage into run on sentences that rain on your parade just to chest pound his 367 as the ultimate engine while downing yours as a waste of time and garbage not worth ****.

Carry on AJ!

He mentioned keeping stamped rockers. And mentioned porting heads at later date.

I was thinking that all could be done in one future upgrade: cam, lifters, rockers, pushrods, Port heads.

 

[dodgedifferent2]

Find a pair of w2 heads and dont look back

 

[Mopar to ya]

Are you running an 11 something on motor now?

Not quite. 12.02 is the best I can get, but that was at Rock Falls, AKA Slippery Rock. Hooking up is an issue.

 

[Toluene56]

I bought a 408 shortblock from blueprint, added my own top end. Runs pretty good for 9.7:1 comp. 12.44@106 3.55 gears @ 6800ft DA. Sea level it would be in the 11's easy.

 

[autoxcuda]

I bought a 408 shortblock from blueprint, added my own top end. Runs pretty good for 9.7:1 comp. 12.44@106 3.55 gears @ 6800ft DA. Sea level it would be in the 11's easy.

What what are the top end details and the cam specs?

 

[rumblefish360]

What what are the top end details and the cam specs?

Maybe this? It fits the said comp ratio.
BluePrint Engines 408CI Stroker Crate Engine | Small Block Chrysler Style | Dressed Longblock with Carburetor | Iron Heads | Flat Tappet Cam

 

[Toluene56]

What what are the top end details and the cam specs?

Cheapo Procomp heads - as cast
Lunati 60413 Hyd Roller cam
Cheapo Chinesium Crosswinds intake (port matched)
AED 750 Double Pumper

 

[flyfish]

Take your time and carefully chose the combo of parts to achieve your goals....for example (not picking on anyone, this just happens to be a good example): My goal was high 10's in my Barracuda....My old 410 stroker combo happens to be VERY similar to "Mopar to ya" (post#2). The main differences were my heads are fully ported, I had less compression (10.8:1) and a slightly larger solid roller cam (248/254 duration with about .576 lift). The last difference is I have an 8" converter in my 727.....His car is running low 12's, mine ran mid 10's, exceeding my goal.

Again, not pooping on anyone, just saying it doesn't take much to make a drastic change in power...its all in the combination.

 

[zsn0w]

Thanks everyone for all the advice. What I'm looking at now for the engine is the 408 stroker bottom end from scat with the 20.5cc dish pistons, 63cc edelbrock heads with 1.6 rockers, hughes 2832 cam, LD340 intake, long headers I have laying around, and a 750cfm holley ultra double pumper. I'll upgrade the headers and the intake to an airgap eventually. Did some digging finally. Found that my rear gears are 3.23 in the rear. Gotta double check the tire size tonight, as it stormed yesterday and I forgot to snap a pic of the wheels when the weather cleared up. But I think I've got a pretty solid plan now so thank you everyone for all the help and suggestions. Really the only above that I'm still a little iffy on is the 1.6 rockers. Using the 2832, I'd have .53/.536 lift with the 1.5s and .565/.571 lift with the 1.6s for intake/exhaust. I feel like this is worth the 1.6s, as the heads should flow up to that point, but I am not 100% sure as I've seen advice against using 1.6s in street cars. The .35 increase in lift just seems like a huge advantage, though.
One other question. If I am using am A833OD, that should allow me to run 3.55 gears in the rear without making it undriveable on the highway, right? I don't plan on driving on the highway everyday in the car but I want to be able to when I need to.

 

[Toluene56]

What flyfish said... Heads and cam are gonna make a huge difference. I just finished hand porting mine (not a lot) but haven't run it yet. Proper converter can make a 13 sec car damn near 11s if it wasn't set up properly. when you get rockers. Get a good set. I was running some cheapo roller rockers And recently got some comp cams ultra Magnum rockerS. The geometry is waaaay different And everything is souch nicer quality wise. Just a word of advice if you take that route.

 

[mderoy340]

Thanks everyone for all the advice. What I'm looking at now for the engine is the 408 stroker bottom end from scat with the 20.5cc dish pistons, 63cc edelbrock heads with 1.6 rockers, hughes 2832 cam, LD340 intake, long headers I have laying around, and a 750cfm holley ultra double pumper. I'll upgrade the headers and the intake to an airgap eventually. Did some digging finally. Found that my rear gears are 3.23 in the rear. Gotta double check the tire size tonight, as it stormed yesterday and I forgot to snap a pic of the wheels when the weather cleared up. But I think I've got a pretty solid plan now so thank you everyone for all the help and suggestions. Really the only above that I'm still a little iffy on is the 1.6 rockers. Using the 2832, I'd have .53/.536 lift with the 1.5s and .565/.571 lift with the 1.6s for intake/exhaust. I feel like this is worth the 1.6s, as the heads should flow up to that point, but I am not 100% sure as I've seen advice against using 1.6s in street cars. The .35 increase in lift just seems like a huge advantage, though.
One other question. If I am using am A833OD, that should allow me to run 3.55 gears in the rear without making it undriveable on the highway, right? I don't plan on driving on the highway everyday in the car but I want to be able to when I need to.

Run the 1.6 rockers, you are going to lose at least .015 lift at the valve with geometry and deflection. If you are going to use an A833OD try the 3.23s first. The OD trans has a steep 3.0 1st gear to get out of the hole.

 

[rumblefish360]

As long as the current head can handle the lift being sought as calculated!

 

[ValiantRacing]

Again, not pooping on anyone, just saying it doesn't take much to make a drastic change in power...its all in the combination.[/QUOTE]

Exactlly

 

[zsn0w]

Got it. Now to start saving up for all the parts haha. Thanks everyone for the help.

 

[autoxcuda]

Thanks everyone for all the advice. What I'm looking at now for the engine is the 408 stroker bottom end from scat with the 20.5cc dish pistons, 63cc edelbrock heads with 1.6 rockers, hughes 2832 cam, LD340 intake, long headers I have laying around, and a 750cfm holley ultra double pumper. I'll upgrade the headers and the intake to an airgap eventually. Did some digging finally. Found that my rear gears are 3.23 in the rear. Gotta double check the tire size tonight, as it stormed yesterday and I forgot to snap a pic of the wheels when the weather cleared up. But I think I've got a pretty solid plan now so thank you everyone for all the help and suggestions. Really the only above that I'm still a little iffy on is the 1.6 rockers. Using the 2832, I'd have .53/.536 lift with the 1.5s and .565/.571 lift with the 1.6s for intake/exhaust. I feel like this is worth the 1.6s, as the heads should flow up to that point, but I am not 100% sure as I've seen advice against using 1.6s in street cars. The .35 increase in lift just seems like a huge advantage, though.
One other question. If I am using am A833OD, that should allow me to run 3.55 gears in the rear without making it undriveable on the highway, right? I don't plan on driving on the highway everyday in the car but I want to be able to when I need to.

I’d sell/trade the LD340 for a used RPM and use the $100 for something that will actually improve performance or reliabilty.

 

[zsn0w]

I’d sell/trade the LD340 for a used RPM and use the $100 for something that will actually improve performance or reliabilty.

How much is a used LD340 worth? You're saying I'd come out $100 ahead by selling it to buy an RPM? I had no clue the LD340 was really worth much, it just came on my Roadrunner (which I didn't even realize until after I purchased it, I thought I was getting the stock two barrel under the air cleaner and was very pleasantly surprised).

 

[mderoy340]

How much is a used LD340 worth? You're saying I'd come out $100 ahead by selling it to buy an RPM? I had no clue the LD340 was really worth much, it just came on my Roadrunner (which I didn't even realize until after I purchased it, I thought I was getting the stock two barrel under the air cleaner and was very pleasantly surprised).

IMO round off the sharp edges of the center divider, stick a 1" open phenolic spacer, and block the exhaust heat crossover on the LD340 and save your money. Port match the intake and heads and clean up the ports regardless of what head you run. The Js and Eddys will definitely improve with cleanup.

 

[autoxcuda]

How much is a used LD340 worth? You're saying I'd come out $100 ahead by selling it to buy an RPM? I had no clue the LD340 was really worth much, it just came on my Roadrunner (which I didn't even realize until after I purchased it, I thought I was getting the stock two barrel under the air cleaner and was very pleasantly surprised).

Seems like people are paying $300 for decent LD340 plus shipping.

I’d ask that or trade for RPM plus $175. Must get good pics of unpainted RPM. Flippers here hide stuff under paint.

[SOLD] - LD340 Intake Manifold

[FOR SALE] - LD340

[FOR SALE] - LD340 intake

$175 will buy you a timing gear setup and oil pump. Or adjustable push rod length checker and then push rods

 

[zsn0w]

Seems like people are paying $300 for decent LD340 plus shipping.

I’d ask that or trade for RPM plus $175. Must get good pics of unpainted RPM. Flippers here hide stuff under paint.

Wow, who knew. Thanks for the advice, definitely gonna go for that in the next few months. An Air Gap would look really nice under the Holley 750 double pumper I've been looking at.

 

[Mopar to ya]

Wow, who knew. Thanks for the advice, definitely gonna go for that in the next few months. An Air Gap would look really nice under the Holley 750 double pumper I've been looking at.

I had a Super Victor on my motor originally but I wanted low end torque, so I went to the RPM Air Gap. I love it. I ran Edelbrock carburetors for years and loved them, but I was thinking about going to E85 and most of those carbs came on the Proform chassis, so I plumbed it all into a Holley 750 double pumper. I like the power, but I have to adjust that freaking Holley all the time. The Eddy I would set and forget and never touched it. All in all though, the Air Gap and 750 is a good combination for that motor.