Next steps for more power - 318

-
MrJLR

MrJLR

Built, not bought
FABO Gold Member
Joined
May 14, 2015
Messages
5,619
Reaction score
6,712
Location
Menifee, California
Just can't leave well enough alone!
My 318 is running GREAT now!
.020" over, stock bottom end
Home porting job on heads
Hughes Whiplash Cam
Doug's D453 Headers
Electronic ignition
Edelbrock 1407 carb

I'm loving the improvements and gonna drive and enjoy it as is for a while...but what would be some horsepower improvements for the future?

I don't want to boost or juice and I don't want to go 340/360.
Ideas for round two?!

Jeff
 
In order of ease and expense:
  1. Thinner head gaskets for more compression. Try copper .021" ones.
  2. Shaved head for more compression.
  3. Bigger valves - 1.88/1.6 will wake her up.
  4. KB167 pistons to give a zero deck height and 10:1+ compression.
Non-horsepower mods to give you better acceleration would include lower gears in the rear and a higher stall in the trans but of course these have their own limitations.

- boingk
 
boingk said:
In order of ease and expense:
  1. Thinner head gaskets for more compression. Try copper .021" ones.
  2. Shaved head for more compression.
  3. Bigger valves - 1.88/1.6 will wake her up.
  4. KB167 pistons to give a zero deck height and 10:1+ compression.
Non-horsepower mods to give you better acceleration would include lower gears in the rear and a higher stall in the trans but of course these have their own limitations.

- boingk
Click to expand...
Bigger valves and more compression. ...is there a good off the shelf set of heads you'd recommend?

Jeff
 
I built a 318 some years ago and it was a screaming little motor. It was bored .030 with Keith Black flat top pistons, ported J heads with 1.88"/1.60" valves, comp XE 268H cam, Edelbrock RPM intake, Edelbrock 1406 carb, block hugger headders, and MSD 6al ignition. Fried lots of tires on a 2wd Dodge truck with a 4 speed.
 
Did you get any time or horsepower for that 318 combo?

Have a set of X Heads and 268 camshaft ready to go. It came with a grab package and a 340 block. The Block needs to be .100 over, so I'm thinking about putting the heads and camshaft on my running 318. Would 350hp be reasonable?
 
MrJLR said:
Bigger valves and more compression. ...is there a good off the shelf set of heads you'd recommend?
Click to expand...

To be honest at this level of performance they are far from holding you back. Get a quote for the heads to be re-valved and shaved a bit and you will then have a ballpark figure.

Aftermarket heads (like Edelbrock RPM's) may flow well but are also relatively costly, and your engine combination will not fully utilise them in its current form. Bang for buck would be getting your current set (or even a junkyard set of 318 heads so you can keep the car on the road) machined and re-valved.

Boedighw said:
Have a set of X Heads and 268 camshaft ready to go... I'm thinking about putting the heads and camshaft on my running 318. Would 350hp be reasonable?
Click to expand...

Depends. It may make that number with a bit of compression and that camshaft but it may not be very streetable. The heads as far as I am aware are around 68cc chamber volume so will keep your comp ratio the same more or less, but flow a lot better.

The camshaft would be getting edgy for a well-modified motor with 10:1+ compression and a modern port-enhanced intake (eg Torker II, Performer RPM or AirGap).

Basically... you will have a screamer of an engine in current form but not a lot under 2500rpm. The raw numbers are harder to put a finger on, but with stockish 8.6:1 compression you would be lucky to see 300hp.

- boingk

EDIT: Here is a good read of a past HotRod Magazine article. They sure get a lot of power out of a 318: Mopar's 318 Engine - Cheap as Dirt
 
Last edited:
Jeff... Absolutely NO MORE ANYTHING till you take it to the strip as it is!!!!! :D

Yes, there are much better heads. Many have put 2.02 340 heads on stock bore 318's with no issue. Your is .020 over..... But as you build more flow, you'll have to follow with more converter...
 
Jeff, you can try what I'm doing with our teen...

I got a set of 67 -920 heads with smaller chambers and the .040" fel pro gaskets. The heads have been ported and 360 valves were installed. This will bring our compression up to 8.3 in a stock 72 block...

The 66 - 67 273 heads will have the smallest combustion chambers and still have the standard intake bolt pattern...

DSC02066 B.jpg


DSC02069 B01.jpg


View attachment 1714967930

DSC02076 B.jpg


DSC02091 B.jpg


DSC02085 B.jpg


DSC02084 B.jpg


DSC02088 B.jpg


DSC02096 B.jpg


DSC02100 B.jpg


DSC02121 B.jpg
 
MrJLR, what size valves are in your heads now? Are they 318 heads? Is your car an automatic, if so maybe a converter upgrade to at least a 2500-2800 would compliment the combo better so as to not tear back into a well running motor.
 
What heads do you have now? The 302/714 heads where a nice boost of power on my teen. I know a lot of people say they are no better than any other 318 head but I'm not sure they are speaking from experience. "Pulls like a 340."
 
racerdan80 said:
MrJLR, what size valves are in your heads now? Are they 318 heads? Is your car an automatic, if so maybe a converter upgrade to at least a 2500-2800 would compliment the combo better so as to not tear back into a well running motor.
Click to expand...

It has stock small valves....but I did home-port the heads.....also running a 2400 RPM stall...wish I would have gone a little higher!

318willrun said:
Jeff... Absolutely NO MORE ANYTHING till you take it to the strip as it is!!!!! :D

Yes, there are much better heads. Many have put 2.02 340 heads on stock bore 318's with no issue. Your is .020 over..... But as you build more flow, you'll have to follow with more converter...
Click to expand...

LOL....not doing anything to it right now! I want to drive her for a while!
I am going to get it to a 1/4 miles track (Fontana) in the not too distant future - I need a baseline to compare future changes to!

I have got to say - it runs VERY strong for a 318....and I also know there's more in there!

Jeff
 
You can gain improvement with a set of 340/360 heads, but it will lower the compression a bit...

However the loss in compression is offset by the increase in flow... You will gain performance overall....

That's why I had the old 273 heads ported and bigger valves installed... they should run as good or a little better than the stock 360 heads, and not hit my compression...
 
my engine shop talked me out of 188s on my 302s, said it wasnt worth the cost, they installed 160 ex vaves and ported them, i read a few articles by a few different sources that back up his claim. no problem pulling 7000 in that teener.it was nice to have a guy talk himself out of more money for his shop and not make me spend more than i had to
 
318willrun said:
Jeff... Absolutely NO MORE ANYTHING till you take it to the strip as it is!!!!! :D

Yes, there are much better heads. Many have put 2.02 340 heads on stock bore 318's with no issue. Your is .020 over..... But as you build more flow, you'll have to follow with more converter...
Click to expand...

Couldn't agree with this more.

your combo need to go to the strip. It likely could be faster simply by tuning and sorting out your chassis.

Then heads and convertor.
 
How about a procharger? They have kits for SB mopar and it will fit under the hood and nothing will add a much power as it will
 
Am I the only sadist who wants to see exactly how much power you can wring out of a stock looking 2-barrel-topped engine?

- boingk
 
boingk said:
Am I the only sadist who wants to see exactly how much power you can wring out of a stock looking 2-barrel-topped engine?

- boingk
Click to expand...
I ran 15.90's at just over 84 mph with a bone stock 318 2bbl. Stock carb, stock exhaust manifolds, stock converter, stock 2.94 gears, stock everything in a B-body. It did have dual exhaust.

I imagine to keep most people thinking it's stock, you could have put a stock 360 2bbl and intake on it, 360 cam, 340 exhaust manifolds, and port the 318 heads. This all would appear stock to your average person but would add up to considerable gains. Then add a better converter and 3.55's. :)
 
Have your new aluminum heads shot peened and paint them. Try to tell the difference. Old Nick Scavo trick
 
You must log in or register to reply here.
-

Back
Top