What I have: '86 4x4 with an oil burner 318-2bbl and NP435 4spd.

What its for: Its my backup daily driver in summer/winter, but mostly its just a toy I throw money at.

What I'm thinking of replacing the LA318 with:

stock 5.2 magnum shortblock
edelbrock 61775 magnum heads
Fel Pro .047 head gaskets
comp 20-746-9 roller cam, re-using stock roller lifters
front accessories off my old LA318 including the means to drive a mechanical fuel pump if thats possible?
Summit headers (SUM-G9042)
Professional products 55026 intake, air-gap knockoff
Holley 3310-2, 750cfm vac sec
Carter M6270 fuel pump, high volume
Mr Gasket regulator, MRG-2015
stock distributor out of my LA318, possible? Its mechanical advance only

So many questions... Are stock magnum pushrods hardened? Are stock magnum rockers adequate? Motor mounts the same? Would the stock mechanical fuel pump be good enough? Would a Carter high volume pump even need a regulator?

One thing that stands out to me already is I would use a thinner head gasket. Assuming your short block has stock pistons and the deck has not been cut, Mr. Gasket .028 thickness would give you a little compression bump. You might also consider a regrind cam and save a couple hundred bucks.

Just did this with a 5.9 magnum. Many aftermarket hyd rollers have extended nose that allows for the stock LA fuel pump eccentric. Eddy heads use a longer push rod than stock. You'll need a 45 degree pipe fitting to adapt the Magnum bypass hose outlet to the LA water pump. You may have to shim the left motor mount bracket, ear distance is different. You can bend the throttle linkage to fit the magnum intake.
https://www.forbbodiesonly.com/mopa...build-how-i-do-it.187572/#post-911485726
Doug

Thanks a ton, sounds like a lot of that information was earned through trial & error, I appreciate you sharing that stuff freely. I've built big blocks & Hemis, but this is my first venture into small-block territory.

I quoted an .047 gasket because... that's just what comes with the cheap fel-pro gasket kit. I wouldn't be above getting a pair of .027 cometics, but it is supposed to be a relatively low buck build. I haven't bought anything yet, just laying out my parts list.

You mention reusing the roller lifters. Would they be sourced from the current engine in the truck? If so, are you sure that is has a roller cam? The few '86-87 318 truck engines I have had were flat tappet cams even though they were roller blocks.

I'd use a 5.9 Magnum instead of the diminutive 5.2.

The 318 mag has more compression and tighter quench, flat piston for better flame travel and less heat soak so the power difference is very small in reality. That said you will make a hair more with a 5.9 but they are not far apart when running stock short blocks.

I was under the impression that all 318's and 5.2's are internal balanced while 5.9's and 360's are external balance. If I swap to a 5.2 I can use the flywheel from my 318.

You are correct. I would caution you that you can't put to much of a cam in the 5.2 magnum with the stock pistons without running into valve to piston problems. I don't know what the specs on that cam are but anything over .470 lift with 212@.050 is probably going to be a problem and that is with the stock .050 or so head gasket. Remember that most of those aftermarket cams are listing the lift figures with a 1.5 rocker and magnums use a 1.6 rocker.

Edit: I just looked up that cam and while it does say it's for the 1.6 rocker ratio i don't think it will fit with .506 lift and 216/224 duration @ .050.