300 HP out of a 318, is it possible with bolt ons?

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madjak.06

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Hey everyone, was wondering if a 300 crank HP 318 build was do-able with bolt ons- and what else might I need to reach that??
318 build list:
- eddy 4 barrel intake & 600 cfm carb with 1 inch spacer
- Mild cam (Hughes whiplash)
- Hedman long tube headers, duals running to flowmaster super 10s
- Jegs distributer and NGK plugs
*Motor is fairly fresh and pulls to 5000+ no problem*

I understand majority of SBM's suffer from flow restriction and deathly low compression, but I do not wish to tear my motor apart soon, and just want a streetable small block for now! If anyone has any idea where I'm at horsepower wise currently or suggestions to hit 300 HP at the crank, please let me know!
 
Sounds like a reasonable plan.
I say, go for it…….and don’t get caught up in chasing a number.
 
282 hp with a comp xe262h cam

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

Show All
HORSEPOWER SUPERFLOW 901 DYNO-TESTED AT WESTECH
RPMBASEMOD 1MOD 2
2,000112
2,500137
3,000164193192
3,500182224227
4,000189248252
4,500186265274
5,000179271282
5,500262270


TORQUE SUPERFLOW 901 DYNO-TESTED AT WESTECH
RPMBASEMOD 1MOD 2
2,000292
2,500287
3,000287338336
3,500272335340
4,000248326330
4500218309319
5,000188285296
5,500250258
 
One day I'll take the time to port the heads, find some hypereutectics, steeper cam, all the goodies!!! Thanks for everyone's responses, for now I'll continue to shoot for 270-300 HP at the crank :thumbsup:
 
Back in the day I would put an LD340 intake on it and a set of X heads off of 340 with a 3500 stall converter and 391 gears or 430 and a 284/484 purp......hang on....
 
Bolt-on's I don't know. Starting clean-sheet but on a budget, get '85-2002 replacement pistons (more compression height than the older pistons, even the 4-eyebrow early style) and start with #302 casting (heart shaped chambers) heads, modified for 360 valves (1.88x1.60"), with chambers deshrouded and bowls hogged/blended. Port match the intake ports to the pushrod pinch to 340/360 size and blend past the pinch. Mill the heads to reduce the volume back down from the deshrouding cuts. Pick a conservative camshaft, at least a 218*@.050" but probably more like 228*@.050" and at least .450" lift up to about .500". The last one I did, I used a 270S Comp Cams solid flat tappet with 273 rockers/pushrods, 224*@.050" with .468" gross lift. Very mild lope and plenty of RPM. I used a single plane intake, but your Performer intake opened-up to 340/360 size, or even a factory 340/360 iron intake would work. Headers are a must, 1-5/8" with 2.5 or 3" collectors. Use a muffler that is straight through with packing, avoid FlowBoys or any chambered muffler. Cherry Bomb Salute and Jones MaxFlow are cheap and sound great with better flow. I use a Flowmaster merge collector and a single 3" muffler/tailpipe to build torque, but 2.5" max duals work too, with a H or X pipe after the collectors. This setup will work on regular pump gas, if your budget allows, run SRP or KB zero deck flat tops and premium gas.
 
madjak.06 said:
Hey everyone, was wondering if a 300 crank HP 318 build was do-able with bolt ons- and what else might I need to reach that??
318 build list:
- eddy 4 barrel intake & 600 cfm carb with 1 inch spacer
- Mild cam (Hughes whiplash)
- Hedman long tube headers, duals running to flowmaster super 10s
- Jegs distributer and NGK plugs
*Motor is fairly fresh and pulls to 5000+ no problem*

I understand majority of SBM's suffer from flow restriction and deathly low compression, but I do not wish to tear my motor apart soon, and just want a streetable small block for now! If anyone has any idea where I'm at horsepower wise currently or suggestions to hit 300 HP at the crank, please let me know!
Click to expand...
Yep, go for it. Sadly, teens don't get put on the dyno very often so there's not a ton of numbers out there. Hot Rod magazine built a 400 horse teen (supposedly) with zero deck pistons, a 230°/.512 Comp Cam The lift was using Magnum heads and their 1.6 ratio rockers. Intake was a MP open plenum with a 750 Demon etc, etc. Here's a link. I think a zero deck Teen with some mildly massaged Speedmaster heads and the right cam could get to 400 horse easily.
https://www.motortrend.com/how-to/mopp-0409-318-engine-build/
 
I would think that is a definite possibility. Heads and their associated airflow could be your biggest problem.
I do have one question though. I have always considered a "Bolt On" to be something like headers, intake manifolds, etc. that we bolted to the outside of a motor. Would we consider a cam swap to be a "Bolt On"? PLEASE don't get me wrong. I'm not trying to hijack the thread be negative, I am just seriously curious.
 
harrisonm said:
I would think that is a definite possibility. Heads and their associated airflow could be your biggest problem.
I do have one question though. I have always considered a "Bolt On" to be something like headers, intake manifolds, etc. that we bolted to the outside of a motor. Would we consider a cam swap to be a "Bolt On"? PLEASE don't get me wrong. I'm not trying to hijack the thread be negative, I am just seriously curious.
Click to expand...
Guess it's how you look at it, To me I'd say any thing where you don't have to pull the engine, if the engine out and you do the short block it be a rebuilt/refresh anyways.
 
In the '80s there was a 318 with W-2 heads in a Colt running 10.90s....was bored to 4.04 (340)..
 
I always thought it was really sneaky with the X block to be stamped 318
 
toolmanmike said:
So it wasn't a 318 any more. :poke: :rofl:
Click to expand...
Yeah, exactly. Sorta like the car in the for sale section now. ....and I quote "Has the original 340 in it now stroker motor with Scat rotating assembly eagle rods. Motor is 30 over and was decked. Runs on pump gas."
 
RustyRatRod said:
Yeah, exactly. Sorta like the car in the for sale section now. ....and I quote "Has the original 340 in it now stroker motor with Scat rotating assembly eagle rods. Motor is 30 over and was decked. Runs on pump gas."
Click to expand...
:rofl: :rofl:
 
toolmanmike said:
Yep, go for it. Sadly, teens don't get put on the dyno very often so there's not a ton of numbers out there. Hot Rod magazine built a 400 horse teen (supposedly) with zero deck pistons, a 230°/.512 Comp Cam The lift was using Magnum heads and their 1.6 ratio rockers. Intake was a MP open plenum with a 750 Demon etc, etc. Here's a link. I think a zero deck Teen with some mildly massaged Speedmaster heads and the right cam could get to 400 horse easily.
https://www.motortrend.com/how-to/mopp-0409-318-engine-build/
Click to expand...
But the 400HP 318 was measured using magazine horse power. That's different, dontchya know? lol
 
Obviously these articles like a lot of car TV shows are just basically commercials, and companies like Comp cam, Holley, Edelbrock sponsors, give free parts to these shows, just so these brand names are gonna be in the forefront of buyers minds cause there use in every build or show.
Doesn't mean the results are fake.
 
madjak.06 said:
One day I'll take the time to port the heads, find some hypereutectics, steeper cam, all the goodies!!! Thanks for everyone's responses, for now I'll continue to shoot for 270-300 HP at the crank :thumbsup:
Click to expand...

Here's a couple of 400 hp 318 builds, see what heads can do down the road if you choose.

https://www.motortrend.com/how-to/318-small-block-build/

https://www.motortrend.com/how-to/0810phr-chrysler-318-engine/

https://www.motortrend.com/how-to/ccrp-0401-mopar-318-engine/

Here's a similar 400 hp 360 for comparison

https://www.motortrend.com/how-to/59l-magnum-engine-make-mine-a-5-9/

If you look at the main difference between these 400 hp 318 vs 360 between peak Torque and HP is rpm, 318 = 4900-6200 rpm 357-400 hp (could argue this 318 has a slightly better under the curve), 360 = 4200-5600 rpm 336-400 hp, would have vary similar power curves, Stall to Shift points if stalled and gear right.

Mopar 318
RPMHPTQ
3,000190332
3,500241376
4,000286376
4,500321375
4,900357382
5,000363381
5,500388371
6,000398348
6,200400339
6,500393318

VS

On The Dyno5.9LMagnum​
RPM:TQ:HP:
3,000407233
3,100406240
3,200406248
3,300409257
3,400411266
3,500413275
3,600414284
3,700415293
3,800416301
3,900416309
4,000417318
4,100419327
4,200420336
4,300419343
4,400419351
4,500419359
4,600418366
4,700416373
4,800413378
4,900409382
5,000405386
5,100401390
5,200397393
5,300392396
5,400387398
5,500381399
5,600375400
5,700367399
5,800361399
5,900354397
6,000347396
 
It can be done. My 318, .030 over, 340 heads, Comp cam XR280HR, LD4B intake. Not sure what else. Still paying.
Dyno Card 3.JPEG
 
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