318 HP build
 

Hey everyone. Im new to the forum and as a result this is my first post on the site.


I wanted to share my current engine build that is a work in progress. It is a LA 318 with some high performance components.


74 318 LA Block

Bored 30 thousandths over

Milled to zero deck height, closer to positive deck height after machining, pistons stick out of the bore


KB 399 hyperectic dome pistons

Cast crank, turned and machined

ARP Main studs

ARP Head studs



360 J heads

Milled 20 thousandths

New valves

New valves guides

New seats

Ported, polished, gasket matched, no radical porting


Comp Cams roller camshaft complete kit

Cam Specs, .513/.498 lift

Advertised duration 283/303

107 LSA


Roller Rockers


Edelbrock performer intake

Summit Holley style 4 barrel, 600cfm, vacuum secondaries


Flowtech headers


This is essentially the entirety of build itself. Built to be an experiment to see how much power it puts out. Will be a street motor/highway driver in a 80s dodge halfton which has a worn 318 with core shift, dramatic cylinder taper and enough blowby that it could potentially turbo charge itself under the right circumstances. This will probably be the last high performance stock stroke small block I build.


Details on the truck


1984 Dodge w150 4x4 Shortbox

727 Auto Trans w/shift kit

~1600 stall torque converter

9.25 rear with 3.21 gears, 31inch tires

(Combo of trans, gears, and tires puts rpms at 70 in top gear around 2500 rpm)

Weight with driver ~5000-5200 lbs


Meant to be a highway driver/daily driver, don't need big block levels of low end torque with this particular truck. Any thoughts, or comments are welcome. Curious what it will put out for power, have a tentative dyno date set up at some point in the future after assembly.


https://cimg4.ibsrv.net/gimg/moparfo...5376903543.jpg

https://cimg6.ibsrv.net/gimg/moparfo...e5e647d9ef.jpg

hey, cool! that sounds to me like it could reach the 330 horse range. are you gonna dyno it?

Welcome to the forum
It looks like you have put quite a bit of thought into this build. My thoughts are you should be looking for a converter with a little more stall maybe in the 2200 - 2400 rpm. Also what is the duration at .050 lift?

Duration at .050 is 227/241 intake/exhaust.

My plan is to dyno it after final assembly for initial break in and then tune it accordingly. Hoping it will put down some good numbers.

That will make it snoty enough, like I said your going to need a converter.

e -

Based on everything you said, I think you might be a little overboard on the cam.
(Check it's rated power band.)
A higher stall converter and rear gear ratio would also help.

Archer

I agree with Archer more gear is needed. 3.55 was common in the 4x4 but that cam and tire combination say 3.91.

The gearing did cross my mind. I do happen to have complete running gear from a 73 parts 4x4, Dana 44/60 equipped with 4.10 gears that would fit this 318 very well but rpms would be far outside of what I would consider highway friendly (with 31 or even 33 inch tires). 70 mph highways around here and 80 mph interstates aren't too far away if I decide to venture any farther than the next town or two over. My plans were to degree the cam in order to tame the powerband to where I would normally drive with the hopes that the compression of the engine itself would help as well. Not sure what the KB399s will bring compression wise, my best guess is at least 10 to 1 with the heads slightly milled and the block decked.

e -

The thing will certainly drive, but you're looking at a high rpm engine. Degreeing the cam may not give you enough to keep it happy on the street, and as far as compression/torque, it's still a 318 in heavy vehicle.

Years ago, I ran a 318 with 340 HP heads and the usual upgrades. With 3.23s in a 9.25 rear, that puppy was pretty snappy, but it had a much lower cam profile.

Unfortunately, you have to be dealing with compromises, unless of course you want to talk to Gear Vendors about an over drive.
Their rig will effectively turn a 4.10 into a 3.23 and a 3.90 into a 308.

Archer

4° advance would help with the bottom end but it just reflects the cams not correct for the aplacation. I think once you have it on the dyno and see the lack of torque down low it will be more apparent what else your going to need.

Power band of the cam is 1600-5600. At least what its advertised at. Comp cams part # is K20-600-9.

I was wrong. 1900 to 5900 is the cams alleged power band. Sorry.

yeah that's... pretty wild but definitely doable!

I what motor, a 318 will be different than a 360...
The 318 will have a higher power band than the 360 by 400 rpm.

Comp Cams didn't specify. It was just billed as a small block mopar cam, in a vague way, same as lunati, and several other others I looked at. Wanted to go roller cam and that was the best option at the time since lunati was out of stock. Still took me a month and a half to get the cam from summit.

Hopefully it works out. I'm optimistic since this motor will be far superior to the worn out 318 that has about sub 8 to 1 compression, zero vacuum, and a habit of using half to almost a quart of 15 40w oil with the majority of it painting the underside of the hood from blowby after a casual 20 mile highway drive. If that motor can move my half ton truck, I'm sure this one will as well.