More power out of the 318

[David]

It looks like I will be pulling the 318 out of my Charger over the winter since something is wrong internally. It has just under 300,000 miles on it. While its out I would like to upgrade some components to get more power. Right now I have a 600 cfm double pumper on top of a Weiand dual plane manifold. I also have headers. I bought a comp cam XE256 with lifters back in August that I would like to get in as well. What else can I do to get more power and realistically how much horsepower can I get with my cam selection? The block is a numbers matching block so do you guys think I should bore it or not? Sorry for posting another 318 question. I have read the other posts but don't know what else needs or should be done. Thanks for the help.

 

[daredevil]

angle mill the heads and add some flattops with a 0 deck. I did this and ran an erson hyd. cam around 450 lift and headers and finished off a lot of 350 chevys. have gears and converter been addressed yet.

 

[Patrick]

To bore or not to depends on cylinder wear. Anyway the cheap way to get dependable power out of it is to bore it to the 340 standerd bore, and use 340, 10 to 1 CR pistons. Take 40 off the heads, pocket port and install 340 valves w/comp springs retainers and locks and be sure to gasket match the ports. The one I made for my son w/thumper cam 750 Edlebrock carb and air gap intake dyno'd at 385 hp, 5500rpm 396 tq at 4600 rpm. On the wild side my own 318/391 stroker makes a tad under 500 hp.

 

[David]

Daredevil I have not addressed gears and converter. Patrick how much did the boring and porting cost if you don't mind me asking? I wanted to get a thumper cam but I originally didn't plan on upgrading alot of the valvetrain. I just found out that either a vavle or my cam is wore out. So I'm stuck with one of there xtreme energy cams wich will limit the amount of horsepower I can put out.

 

[rumblefish360]

Patrick, I know your a good fella here, but I have to correct you, so don't take offense to it and when I say, you were lied to when they told you half of this that went on.

Anyway the cheap way to get dependable power out of it is to bore it to the 340 standerd bore, and use 340, 10 to 1 CR pistons. Take 40 off the heads, pocket port and install 340 valves w/comp springs retainers and locks and be sure to gasket match the ports

You can not bore a 318 out from a 3.91 - 4.04
With 340 10-1 pistons, they must be the positive deck height slugs, which would cause a serious problem with milling the head .040.
I myself am not sure installing 340 valve gear on a teen with HIS cam shaft is a good idea.

Daredevil also suggested angle milling in which I really do not see the need since we allready have a superior valve angle and a few degrees more on a street engine is very very small potatos. Though enuff of them, it'll add up.

I wouldn't do the angle milling myself. Your call.

David

With the cam you have, I myself would look at the next one up that I think comes in @ a duration @ .050 of 218-ish and the exhaust of 6* or so more. (I just dn't have the book infront of me to be precise.)
I would look to the KB 318 pistons that come in around zero deck, though they not need be there with this cam.
Pocket porting the head I agree with, but with the 1.88 valve for the intake and YES! The 1.60 for the exhaust.

 

[David]

Hey guys thank you for the input so far. I don't know much about internal components because I've never taken a motor apart but thats how you learn right, so thanks for the help. But the cam I have the specs are duration @ .050" lift is intake 212, exhaust 218. Rumblefish this is the summit part number UEM-KB167-STD are these the psitons you are talking about? Also the 1.88 valve for intake and 1.60 for exhaust are the porting specs right?

 

[rumblefish360]

I do think those are them. Just order them after the block is bored and the machinest guives you the nood as to the size you'll need. AKA .020 over or .030 overbored. KB may only offer them at .030 overbore size, but that's a bridge you'll cross later.
No biggie.

Also the 1.88 valve for intake and 1.60 for exhaust are the porting specs right?

Those are not porting specs but the upgraded valve size for a nice high performance 318/360. Given the size of the cam this valve size is a judgement call for you. (The cam is small) and any port work should be limited to just under the valve. (AKA 5 angle valve job)

 

[ACME A12]

...just a thought...and not an original one either...but there's no substitute for cubic inches...especially in a car of this size...

I love LAs...in an A-Body...JMHO

:yes:

 

[David]

I agree ACME, I would love to have more cubes. I was quite impressed when my car beat a monte carlo ss 350 (believe he rebuilt the top half) heads up and when he had a half car lead :grin:. I also lost to an 05 audi tt quattro by a car length maybe a car and a half. I have enver dealt with a machine shop. SO do i need to bring the block in so they can look it over and tell what they can do? Or can I just tell them what parts I have now and what I would like to accomplish and see what they say?