i got 79 powerwagon im going rebuild my 318 im going use 302 fast burn casting heads im look for good low end power to mid range and bring compression around 9s or 10s im have trouble with piston choice i dont wont use speed pro or keth black i dont wont use piston that got the coating on piston skirt look for good flat top 4 Valve Reliefs any buddy hear about DNJ ENGINE COMPONENTS Part

Just a suggestion but why not build a 360, won't cost any more to build than the 318.

You might check out the 318 piston offerings from www.hughesengines.com. I would strive for .035-.040" quench which would be doable with those closed chambered heads. Being cube limited you need all the torque you can muster & quench will let you run a higher CR along with a good curve on a particular fuel for more power. I'd suggest a 1.88 intake & some bowl hogging/mild porting to clean things up a bit. Google the 302's as there's some good info out there on them just depends on how much time(& money) you want to invest

true reason i wont do build build on my 318 it numbers match block in my 79 powerwagon i wont use 302 heads and my 69 340 square bore intake port heads to match intake run 68 spec 340 cam just try find right pistons to run in my set up heard lot bad things about Hypereutectic and coated piston skirts im going use molly rings wont to bring compression up to 9s and ideas would be great will not be use stock tin head gaskets

im hope i can find pair 302 heads im take hipo at wyotech so il be able port and polishing and bowl work it want cost me dime thanks il take look at www.hughesengines.com. it 79 powerwagon look build some with good low to mid power toque i dont any thing to crazy it going be my dally driver tow a car hauler

Since your going to wyo tech, you ought to look at machining a 360 crank to fit in your 318. That should give you a nice torque boost at the low end

Do they teach spelling and punctuation at Wyotech?

Sorry, it's just hard to tell what your saying, or asking, when you keep using "wont" in place of "want".

i wont apologize for my spelling and punctuation i know it Wyotech yes i could do that with a 360 crank what about put in a 340 factory steel crank

here what i wont do to my 318 in79 power wagon Hughes whiplash camshaft icon full floating pins FORGED PISTON 3.91" X 3.313" STROKE FLAT TOP -4.73CC DOME VOLUME STOCK STROKE and molly rings with set mild ported and bowl work 302 heart shape combustion chamber closed chamber heads with stock crank and rods top off with factory 69 340 square bore intake top off with demon 625 carb should be strong motor look for low end to mid range power and torque what do yall think

Money spent on a 340 crank would be much better off spent on more cubes. Forged isn't necessary for your power levels

true i dont want go to crazy with my build just wont good dally driver that got good low to mid power and torque that sounds healthy on stock bore and stroke thanks for the help

It's really hard to parse your posts, so if this advice goes contrary to what you posted I apologize.

I'm not a fan of 302 casting heads as the valves and the runners are really tiny. To make them worth anything you need to do some port work and bump the valve size up to 1.88". With better factory castings out there I don't think they're even worth the expenditure.

I would either use a set of Magnum cylinder heads, or better yet, just get an entire 318 Magnum motor. Even with a factory rotating assembly and cam in it they're good for 250 horses with just bolt-ons; mileage should still be pretty respectable too.

I run a hughes whiplash roller cam in my stock 91 318 with the #302 heads with comp 901-16 spring all stock roller non-adjustable valve train.

my combo in a 85 stepside

91 JY 318 100,000 + miles

Holley 6210 650cfm spredbore mech dbl pumper
Holley street dominator intake
hughes whiplash roller cam
hedman hedders 2.1/4 pipes 2 chamber muffs turn downs at rear axle
NV4500 5 speed
9 1/4 with 3.55 lockright locker 29x9.50x15 tire

nasty idle with plenty of torque on tap and gets 18+mpg

Here's the drill: a 30 over 318 comes in at 323 cubic inches. Doing the math each cylinder has a volume of 662cc. To get to 9.5:1 compression ratio you need 77.8cc above the piston.

Assume that by the time you get your heads ready to go they have 63cc volume.

Use a Mr. Gasket thin head gasket I believe it's about 5cc. So you need about 10cc more, that puts the piston 0.050" down in the hole.

Say your block specs in at the standard 9.600, you have 6.123 rods and 3.31 stroke, the piston pin will be 1.822 down in the hole. So with a flat top piston you need a compression height of 1.822 - 0.050 = 1.772 to get to your dream.
There isn't a single 318 shelf stock piston with anywhere close to that compression height. The tallest 318 LA piston is for the '89 - 92 Mag motor, comp height 1.755. Slightly earlier is 1.745. Both are flattops.

The first piston with valve reliefs is 1.720 comp height. Plus the valve reliefs add maybe 4cc to volume, lowering the compression ratio even more.

There's even a piston with 1.658 comp height for really low compression engines.

The three most dangerous words in engine building, or life, are "I have heard".
Coated pistons are bad? Hypereutectic pistons are bad? Then why are nearly all of the new engines being built today with pistons made of a hypereutectic alloy and coated? KB is bad? They have a thriving business and have had one for years, surely if they were so bad they've have starved to death long ago. Speed Pro is bad? Their pistons are heavy it's true, but they are virtually indestructible. And they are built by Sealed Power, the company who has for the last half a century or more supplied a large percentage of OEM pistons to American manufacturers. Speed Pro forged pistons are the old TRW forged pistons. TRW sold decades ago.

The only shelf stock piston that comes anywhere near doing what you want is the Keith Black, or you can always go forged. You can get a custom forging any way you want, as long as you can pay for it.

R.

I agree with dogdays my 323 CID 1974 318 block has Keith Black pistons that brought the piston height up from about stock to just about 0 deck. This alone brought the compression up from 8.6-1 to 9.0+ before any other work.