Installing small cam in Stroker?

[autoxcuda]

I never said 2 tenths, 5.9l was stock cr and 410 was 10.73:1 so about 1.73:1 gain if stock is 9:1.

Ok that is a big difference. I wouldn't have imagined they would call that much compression difference a fair comparison.

And a 10.73:1 stroker motor with that bone stock cam isn't going to run a pump California 91 octane around here.

The OP is starting out with a cam that seems a little bigger than the 2nd cam they put in that 360/408 test. And better heads. Wonder if that more performance starting point would respond the same.

 

[273]

Ok that is a big difference. I wouldn't have imagined they would call that much compression difference a fair comparison.

And a 10.73:1 stroker motor with that bone stock cam isn't going to run a pump California 91 octane around here.

It would've been better but they were building a like 500 hp 410 this was just one of those I wonder if/ would do kind of thing, wouldn't make sense to cripple the final build.

The OP is starting out with a cam that seems a little bigger than the 2nd cam they put in that 360/408 test. And better heads. Wonder if that more performance starting point would respond the same.

That second graph was just a 5.9l before and after cam change, just to show what gains a mild cam would do to a magnum instead.

Here's a neat displacement shootout even though it's Chev, I think it's a good representative how displacement can move the powerband.

There the same factory combo's, 302 vs 327 are identical vs 350 that does have a slightly different cam otherwise the same.

I know everyone gonna say 350 wins cause of torque and I think in a streetable sense It does cause it operates at street friendly rpms. But if all geared and stalled optimally they should be similar performers.

 

[Brooks James]

2 tenths of a point ? That not much.
How much HP and torque gain/loss are you attributing to 2 tenths of a compression?

I think the original poster could go to a very slightly larger cam and have the same vacuum and idle characteristics as the smaller cam in the shorter stroke and size motor.

I tried to look up HP increase per point of compression
3-5 percent increase in power

 

[273]

Here's the before dyno 305 hp after 334 hp so a 29 hp gain, say 15 hp from cr 5% total, that's like 14 hp peak gain. Seems like the gain minus the cr gain be mainly between 2800-4000 rpm area.

 

[mgoblue9798]

On you tube
Some guys took a 360 out to a 408. All else the same, only added 34 hp

But how much torque was added? I'd hazard a guess of 50 lb ft across about a 2k rpm spread.

 

[mgoblue9798]

I've always been a fan of so-called "undercammed" builds. I built a 416 back about 1995. I dressed it out like a stock 340 including 340 exhaust manifolds and the 340 camshaft. Ported J heads with 2.02 valves, stock 71 cast iron intake and a Demon Sizzler Thermoquad. Put a warmed up 727 behind it with a 3.23 sure grip in an 8 3/4. Stuck it in a 67 Dart GT. That thing had so much bottom end torque it'd scare you. I never got to run it, because somebody wanted it more than I did and offered me way too much money for it. lol

Here's how I see it. If a small bore and stroke would fill all the bills, then why did auto makers make big blocks? That's essentially what you're doing building a stroker, is making a big block. Big block stroke. Trust me. A small cam in one will give you gobs of immediate torque just off idle, right where you want it on the street.

Exactly. The 440 magnums were under cammed with a 268 degree intake duration from the factory. Not every engine has to wind to 6 or 7k to make decent power for a street motor.

 

[273]

But how much torque was added? I'd hazard a guess of 50 lb ft across about a 2k rpm spread.

Post #29 shows the dyno charts, technically 76 lbs-ft peak gain from a combination of stroke and CR increase.

 

[rod7515]

In the early 70’s i had a 440 that i added a cam with a .510 lift and if i rememeber a duration of around .220. It was in a cuda and i had a stock converter and 456 gears with posi. I ran 12.10 on a weekly basis for 2 years. I was in my early 20’s having fun and knew nothing.
Fast forward to 5 years ago i decided to build a 66 Dart to do some bracket racing. I had nit hqd a muscle car for 35-40 years. I took a 360 had ut nored .030 and put a set of good steel ported heads on it, a cam with .575 lift and .308 duration solid rollers. I had it stroked and added an old style 2x4 setup, and TTI headers. Compression is at 10.5-1. A light build of a 904 trans with a 3800 converter. Then a set of 456 gears and a mimi spool. Some suspension upgrades and slicks. So how fast does it go? I dont know because it scares the hell out of me when i test it on street. Its so much quicker and powerful them my 440 ever was. I didnt expect that. Love the car and its drivability is awesome as the idle is nice and its not jerking when in gear at stop signs or lights. No overheating isues at all.
Trying to get some courage up to make a pass or 2. Lol.
Rod

 

[Dave_J]

My "Scat" 410 stroked 5.9 is running Eldy NHRA Alumimn Magnumn heads with a closed chamber at about 10.2:1 and a good bowl and pocket port. It has Chevy style 16:1 rockers. Shorty headers into an X pipe then I have an exhaust bypass so I can switch to run thru 2 mufflers or out the stacks on my LRT.
I will be running a Luniti cam. 0.549In and 0.565Ex, 219 In @ 0.050, 227 Ex @ 0.050.

It will be spring before I get it on the road.

 

[RustyRatRod]

For a great example of what stroke can do for torque, look at the Buick 350 engine. For 1970 only, they had the 350-4-SP. 315HP, but 410LBFT. From an under square engine. 3.8 bore and 3.85 stroke. Even the "baddest of the bad" 1970 LT1 Chevy 350 was "only" 370HP and "only" 380LBFT. I'm here to tell you, if an LT1 Camaro lined up against a Skylark with an SP Buick 350 under the hood, he best be careful, because he mightta got his azz handed to him. It's a good thing Buick never made an F body.

 

[1bad360duster]

My builder just finished mine( he still has it). I can’t wait to run it!
The cam grinder had all the car specs which includes being at 5k feet.

I wanted a street engine that would be easy on the valve train.

1970 340/418. The cam is fairly small and, like Rusty said, makes some torque.

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Man awesome build, any more details on it? What heads, is the tr5 ported, compression etc? Looks great

 

[coloradohill]

Man awesome build, any more details on it? What heads, is the tr5 ported, compression etc? Looks great

Thanks, The heads are Indy 360-1.
I found this top end setup here.

[SOLD] - Indy 360-1 Heads, Top End Kit

The intake isn’t ported, I’ve run it on my stock stroke 340 with 660 center squirters for a couple of years and it did well.
This time I have custom Holley 550’s from Allstate Carbs in NY.

It’s a custom solid roller cam (I’m at 5000 ft.).

CR is 11.3:1

Molar rotating assembly from @PROSTOCKTOM

Here is a thread I started when I was deciding whether to keep these heads or go with something else.

Head flow and power differences question / discussion

The builder said it ran great on the dyno . He was impressed on how smooth it ran through all rpm ranges. (he has built a lot of race engines).

He didn’t push it while running it, mainly to break it in and get some numbers for me.

I’m looking forward to running it , should be a fun street car.
I came across an Andrew’s Racing 904 rmvb and converter never installed locally. So that will be going in.

This photo is a few years ago with the stock stroke 340 and tunnel ram.

 

[BSB67]

Was just thinking, since many of us are always worried about to big. Former bottom of the page guy many years ago.
We all know what to big does, I hope.
Figured it would be a good subject.
Smaller than most would go, in say a 408,416,422.Something small like 218,222 @50 high lift like Engle, Hughes, Comp, fast rate right under, over .500
10-10.5, aluimiunm heads light port to clean up/ port match. duel plane with 4bbl or six pack
2.5" exhaust on 340 manifolds cleaned up some or small headers like Dougs.
Something that would run
A/C. Pull toqure on street and have big Cubes on highway.
Or just a waste of a stroke

Never a waste of a stroke.

 

[1bad360duster]

Thanks, The heads are Indy 360-1.
I found this top end setup here.

[SOLD] - Indy 360-1 Heads, Top End Kit

The intake isn’t ported, I’ve run it on my stock stroke 340 with 660 center squirters for a couple of years and it did well.
This time I have custom Holley 550’s from Allstate Carbs in NY.

It’s a custom solid roller cam (I’m at 5000 ft.).

CR is 11.3:1

Molar rotating assembly from @PROSTOCKTOM

Here is a thread I started when I was deciding whether to keep these heads or go with something else.

Head flow and power differences question / discussion

The builder said it ran great on the dyno . He was impressed on how smooth it ran through all rpm ranges. (he has built a lot of race engines).

He didn’t push it while running it, mainly to break it in and get some numbers for me.

I’m looking forward to running it , should be a fun street car.
I came across an Andrew’s Racing 904 rmvb and converter never installed locally. So that will be going in.

This photo is a few years ago with the stock stroke 340 and tunnel ram.

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Really cool build and car. The power is pretty great, and kind of surprising as the unported tr5 has pretty small runners as cast.

 

[coloradohill]

Really cool build and car. The power is pretty great, and kind of surprising as the unported tr5 has pretty small runners as cast.

Thank you , I do have the Indy intake also and have thoughts of trying it sometime just to see what it’s capable of.
Maybe if I get bored. But I wanted the builder to match the tr to the Indy heads so that’s what was sent to him.

Like I said in another thread, if my car is ever finished, I will be also.

 

[a-bodyguy]

For a great example of what stroke can do for torque, look at the Buick 350 engine. For 1970 only, they had the 350-4-SP. 315HP, but 410LBFT. From an under square engine. 3.8 bore and 3.85 stroke. Even the "baddest of the bad" 1970 LT1 Chevy 350 was "only" 370HP and "only" 380LBFT. I'm here to tell you, if an LT1 Camaro lined up against a Skylark with an SP Buick 350 under the hood, he best be careful, because he mightta got his azz handed to him. It's a good thing Buick never made an F body.

The 350-4 skylarks were slowwwwww and lt1 would suck the paint off it.
That 410 torque was over rated never made that on a dyno
avg lt1 low 14s
avg 350-4 15 flat