Better Torque From A 318

[Dan the man]

I don't have a car at this time. I'm researching ways to improve both the torque and throttle response of a 318. I've always liked learning about ways to improve a engines performance. I've read that short duration cams are one way, but what about cylinder heads, what runner size, valve sizes to use? Compression ratio, open or closed chamber cylinder heads? Header tube size and exhaust pipe diameter. Ignition timing. I saw a couple of threads earlier on the 318 but I didn't want to hijack another person's thread. I'm working on being more open minded on things and not trying to come off as a expert on anything. I really hate that I missed out on the 1972 dart, but I'm looking steady and looking farther out. Thanks everybody.

 

[Scody21]

All those things have something to do with making more power…. But the biggest one is being willing and able to take a big stack of greens backs and walk out back of your house, put them in a fire pit, douse them in some alcohol and set them on fire… and be willing to watch them burn, cus that’s what it’s like when you start even thinking about spending money on building an engine… So just find a car, drive it and enjoy, cus your not really going to feel the extra 50 horse power from doing some basic mods…

 

[ch1ll]

Increase Compression is your first choice to gaining more torque. Then keeping it with a small overlap cam.

 

[dirty white boy]

best way to get torque outta a 318 is to 4 inch stroke it to 392, top with best heads you can afford!! remember to build the car and not just the engine!!

 

[ch1ll]

Stroking my second choice, but then again you want make up your mind as you don’t want to buy new pistons twice.

Look at all the 60’s big boats, Cadillac, Buick, Pontiac, all had big displacement, long stroke engines.

 

[318willrun]

I don't have a car at this time. I'm researching ways to improve both the torque and throttle response of a 318. I've always liked learning about ways to improve a engines performance. I've read that short duration cams are one way, but what about cylinder heads, what runner size, valve sizes to use? Compression ratio, open or closed chamber cylinder heads? Header tube size and exhaust pipe diameter. Ignition timing. I saw a couple of threads earlier on the 318 but I didn't want to hijack another person's thread. I'm working on being more open minded on things and not trying to come off as a expert on anything. I really hate that I missed out on the 1972 dart, but I'm looking steady and looking farther out. Thanks everybody.

Any 318 that runs will produce MORE torque than the 318 you do not have.

sorry Dan, I had to .....

 

[mygasser]

here we go again

 

[273]

If talking low speed torque idle to 2500 rpms or so there's little to be gained over stock.
And torque to build hp at these rpms is pretty inefficient at 1313 hp is 25% of tq and 2626 rpm hp 50% of tq so it takes big changes in torque to make/loss hp.

Displacement number one, torque per cid operates in a relatively narrow range for mildish builds 1 -1.2 lbs-ft per cid. Torque is displacements and it's VE% and efficiency mainly CR.

The trick on a street performance engine is how much 3500-5500+ rpm tq/hp gain without overly negatively effecting under 2500 rpm, also a lighter car with deeper gears higher still more cr etc.. Moves the lowest rpms you have to worry about somewhat.

Below you can see at 3000 rpm would be over 50 lbs-ft over a complete stock 2bbl 318 with manifold's and add about 3-4% more with decent cr.
Modded Test don't go down to 2000/2500 rpm but obviously there probably still some decent gain over stock and it wasn't done by strangling the engine.

https://www.motortrend.com/how-to/mopp-0312-318-long-block-bolt-ons/

here the tq on a stock 2bbl 318 with headers Base

xe262h cam 4bbl added mod 1

spacer add mod 2

RPM	BASE	MOD 1	MOD 2
2,000	292
2,500	287
3,000	287	338	336
3,500	272	335	340
4,000	248	326	330
4500	218	309	319
5,000	188	285	296
5,500		250	258

HORSEPOWER SUPERFLOW 901 DYNO-TESTED AT WESTECH
RPM	BASE	MOD 1	MOD 2
2,000	112
2,500	137
3,000	164	193	192
3,500	182	224	227
4,000	189	248	252
4,500	186	265	274
5,000	179	271	282
5,500		262	270

 

[rumblefish360]

And there’s our resident expert without ever building an engine citing others work.



No one should answer a single question of your Dan.
But I’ll go over some basics.

I don't have a car at this time.

Get off the lot or take a ****!
LMAO COULDNT HELP MYSELF

I'm researching ways to improve both the torque and throttle response of a 318.

I proving torque on any old engine starts with increased compression and a larger but still small in size cam shaft.

I've always liked learning about ways to improve a engines performance.

Same as above.

I've read that short duration cams are one way, but what about cylinder heads, what runner size, valve sizes to use?

This depends on the level sought.
With cylinder heads and a 318, this combo is rarely researched. The reality of it all is it’s all in the combination. Your not going to see a good increase with racing cylinder heads on a stock 318, but, if you built a racing 318 w/13.5-1 compression and a whooping solid roller, then that W9 or Victor head is ideal.

For the street, a ported 318 head is very good. A 340/360 head might be better if the combo is right. But what is street performance but an opinion and what one is good with behind the driver seat.

Compression ratio, open or closed chamber cylinder heads?

This is another combo dependent issue and sometimes it is what the builder likes better. Some guys go fora flat top and a closed chamber head. I like that in the 340/360/400+ combo. Works well on the street as far as I’m concerned.

Others will go right to the domed piston and an open chamber as well as sometimes run the piston above the blocks deck. Like the old 340 with a positive piston at .018. I have that now on my destroked 360 @ 352 cubic inches.


Builder’s choice!

Header tube size and exhaust pipe diameter.

Street? 1-5/8 will cover it most of the time.

Ignition timing.

Camshaft, compression ratio, gear ratio, stall converter, tire size, car weight, etc…. dependent.
Just because the engine likes, let’s say, 20* initial, 13* mechanical for 33* at wide open throttle doesn’t mean it’ll work great in the car.

I saw a couple of threads earlier on the 318 but I didn't want to hijack another person's thread.

Why? You’re great at it!

I'm working on being more open minded on things and not trying to come off as a expert on anything. I really hate that I missed out on the 1972 dart, but I'm looking steady and looking farther out. Thanks everybody.

Step one, get a car.
Step two, ask a question about the car you own.

 

[67Dart273]

1......Install small port small chamber 273 heads.

2......-------------------------------------------------------------

 

[rumblefish360]

That might not be needed since the closed chambered head was used a lot on the 318. Same basic head between them.

 

[340six]

Dan, Get the bandsaw guy to help with mods on the pretend engine.

 

[dirty white boy]

in short,..heads make the power, bore stroke and cam decide at what rpm! best motor ever ant gonna be nothing if rest of car ant built to suit!! its all bout combination!

 

[OldmanRick]

Poor Dan, always getting grief...

If you really want a teen, get a Magnum, blueprint it to death, decent ''mild'' roller and the typical bolt on's.
Put in the lightest car you like/can afford and drive the wheels off it. Just about any A body would be fun with that engine. Adjust your conv/gear/tires for how fast you want to go.

I cant tell you how much fun i had on the streets with multiple 13sec cars i owned.....yep, i'm old.

 

[Dan the man]

And there’s our resident expert without ever building an engine citing others work.



No one should answer a single question of your Dan.
But I’ll go over some basics.

Get off the lot or take a ****!
LMAO COULDNT HELP MYSELF

I proving torque on any old engine starts with increased compression and a larger but still small in size cam shaft.

Same as above.

This depends on the level sought.
With cylinder heads and a 318, this combo is rarely researched. The reality of it all is it’s all in the combination. Your not going to see a good increase with racing cylinder heads on a stock 318, but, if you built a racing 318 w/13.5-1 compression and a whooping solid roller, then that W9 or Victor head is ideal.

For the street, a ported 318 head is very good. A 340/360 head might be better if the combo is right. But what is street performance but an opinion and what one is good with behind the driver seat.

This is another combo dependent issue and sometimes it is what the builder likes better. Some guys go fora flat top and a closed chamber head. I like that in the 340/360/400+ combo. Works well on the street as far as I’m concerned.

Others will go right to the domed piston and an open chamber as well as sometimes run the piston above the blocks deck. Like the old 340 with a positive piston at .018. I have that now on my destroked 360 @ 352 cubic inches.


Builder’s choice!


Street? 1-5/8 will cover it most of the time.


Camshaft, compression ratio, gear ratio, stall converter, tire size, car weight, etc…. dependent.
Just because the engine likes, let’s say, 20* initial, 13* mechanical for 33* at wide open throttle doesn’t mean it’ll work great in the car.


Why? You’re great at it!



Step one, get a car.
Step two, ask a question about the car you own.

I knew that I shouldn't have asked anything.

 

[Dan the man]

Toolmanmike, please go ahead and remove this post. Thanks

Dan, Get the bandsaw guy to help with mods on the pretend engine.

Sounds like you don't believe in others asking questions.

 

[junkyardhero]

don't over cam it, don't over carb it.

get some reasonable compression, decent heads, 1 5/8 dia full length headers (tri-y, etx, non fenderwell), dual plane, 600~750 cfm carb, factory electronic ignition.

since you're setting the dial to "stun" and not "kill" anything from a "302" to a 360 2bbl head will be fine-- adjust compression as necessary.

converter and gears are going to make more of a seat of the pants difference than an extra 50 tq or hp.

 

[Dan the man]

@340six, I saw that you gave me a red X. Was the question confusing to you? FYI you always don't need to have a car in order to want to learn something.

 

[Dan the man]

don't over cam it, don't over carb it.

get some reasonable compression, decent heads, 1 5/8 dia full length headers (tri-y, etx, non fenderwell), dual plane, 600~750 cfm carb, factory electronic ignition.

since you're setting the dial to "stun" and not "kill" anything from a "302" to a 360 2bbl head will be fine-- adjust compression as necessary.

converter and gears are going to make more of a seat of the pants difference than an extra 50 tq or hp.

You probably were the best help. Thanks

 

[junkyardhero]

You probably were the best help. Thanks

look, i give you a lot of **** and play around a bunch but when you ask reasonable, real questions i'm happy to help. i'm glad that you've turned the page and are actively trying to learn rather than just regurgitate information you've picked up elsewhere.

research and read everything you can. there are some very smart people on this board (i am not among them) that have been building and tuning motors for longer than i've been alive and have proof positive of what works and what doesn't. in turn there are people here that are firmly entrenched old skool and are still building motors like they did 40 years ago and refuse to adopt any new ideas or practices. there are also people who are only focused on performance and not street manners or driveability. keep all of that in mind when parsing responses.

recognize that there is no one answer.

but cart before the horse and all that: get a car first then start asking motor questions.

 

[Dan the man]

look, i give you a lot of **** and play around a bunch but when you ask reasonable, real questions i'm happy to help. i'm glad that you've turned the page and are actively trying to learn rather than just regurgitate information you've picked up elsewhere.

research and read everything you can. there are some very smart people on this board (i am not among them) that have been building and tuning motors for longer than i've been alive and have proof positive of what works and what doesn't. in turn there are people here that are firmly entrenched old skool and are still building motors like they did 40 years ago and refuse to adopt any new ideas or practices. there are also people who are only focused on performance and not street manners or driveability. keep all of that in mind when parsing responses.

recognize that there is no one answer.

but cart before the horse and all that: get a car first then start asking motor questions.

THANKS AGAIN

 

[Garrett Ellison]

Others will go right to the domed piston and an open chamber as well as sometimes run the piston above the blocks deck. Like the old 340 with a positive piston at .018. I have that now on my destroked 360 @ 352 cubic inches.

Are you doing this with one of the mopar 3.4-3.5 inch cranks and some 1.80ish compression height 340 pistons? I don't recall having seen any postings on that particular engine before, but I apologize if I have... I've recently joined the positive deck club, I've currently got an above deck 340 inch combination that I'm contemplating on the parts to complete.

 

[Garrett Ellison]

As far as looking for a fun go fast ride, find a D100 or D150 SWB with a slant six O.D. or a 3.9 and a 5 speed and build a late 318 (or better yet a late hydraulic roller 360) and put a direct high four speed in it and go have some fun with it. You can still find some reasonably priced on marketplace...

 

[dirty white boy]

As far as looking for a fun go fast ride, find a D100 or D150 SWB with a slant six O.D. or a 3.9 and a 5 speed and build a late 318 (or better yet a late hydraulic roller 360) and put a direct high four speed in it and go have some fun with it. You can still find some reasonably priced on marketplace...

i daily drive a 80 D150 step bed with /6 od833 and love it! few ask when im V8 swaping it i just shake my head no!! but it would be so easy to do!!

 

[Garrett Ellison]

I've got a 3.9 NV2500, 3.90 8-1/4 that's going to be upgraded sometime... but I love it the way it is too much right now! I've converted it to manual steering and electric fan, and it can do a 120 mile round trip on less than 6 gallons of fuel through the mountains and a 1,000 pound load on the way back... no need to mess with perfection yet!