just bought a 318 poly help
 

I just recently acquired a 1969 w200. After talking to the former owner and doing quite a lot of research I have a few questions. I am now 100% certain that the motor is a 318 poly. Is this a motor that was offered in the 69 w200? The motor appears to have a manifold leak. Are the exhaust manifolds the same for the poly and the La block? If not is there anyone who knows where to find them? All I can find are headers but really don't want to shell out th2 $600+ being that I am planning to do a 4bt swap in the near future. Thank you for the help I really like the truck but the motor has become a real pain.

IF it is a poly 318 it is not original..

X2 with what TV said. You most likely have a 318 LA motor as they came out in 1967.

My understanding is that the Poly and La motors are indeed very different and don't have any parts that are interchangeable. I do not know this first hand though.

Unfortunately I am 100% positive at this point that it is a 318A block or poly block. Through quite a lot of research I have found there are a few interchangeable parts but no mention of exhaust manifolds though it sounds very unlikely. Like I said I am not looking to keep it in the truck long.

If this truck is not your DD, then I would invest your money into the parts you need for the swap rather than into the motor that is currently in there now.

Take some pics of the motor. Some members on here may be able to tell you what it is just by looking at it. Also, there should be a stamped code on the side of the block (not sure which side on the poly blocks), that will help in determining what it is.

i may not be of help. but chrysler didnt all ways use the same engines in trucks as cars. i do know the 413 last used in cars was 1965, 10.0 CR, but used them in trucks to about 1972- 1973. my dad used a truck 413 pistons to rebuild a 1965 car engine to lower the CR to 7.5. didnt even have to rebalance the crank. it really worked great.

There should be NO question in your mind as to whether this is a poly or LA engine. First, both engines have the distributor in the rear of the engine. As old as a 69 pickup is, I find it completely possible that someone may have swapped a poly into the vehicle at some point. "Backyard mechanics" do a lot of things. A 440 I used to have, over the years, was put into a former 360 powered 74 Dodge, and after some kid wrecked it, the frame and drivetrain was swapped under a 70's Chev pickup!!!!

If the exhaust side of the valve covers are scalloped, it's a Poly

If the valve covers have "straight" side edges, it's an LA

The exhaust manifolds on ANY LA and any poly are vastly different.

All LA engines have the familiar manifolds where the end port bolt holes are at a diagonal All Poly engines have the manifold bolt holes vertically one above the other

Below are LA manifolds. There are many overall shapes over the years, just look at the bolt holes

http://i855.photobucket.com/albums/a.../manifold1.jpg

Below are Poly manifolds with the distinctive vertical bolt holes

http://3.bp.blogspot.com/_np-yImlIYx...e+manifold.jpg

Poly engine: Scalloped valve covers, and the cover bolts go through the tops of the valve covers, where LA are bolted down on the edges. This is a photo I swiped off the www. You can just see the top exhaust bolt bosses for the 3 rear cylinders

Attachment 13186

Nice post, 440roadrunner.