Poly to LA block swap questions

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Farmall1938

318 poly owner
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Jul 13, 2006
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Hi... I have a dodge truck (I know, I know... not an A-body.... <WINCE>) that has a poly 318 in it. Are these engines known to be weak near the top center water ports on the block at the head mating surface ? Mine is cracked on both sides of the block. This leads to the question about swapping motors. I found online (at the polyspherical association) that the poly blocks have the same mountings, bell housing pattern, and flywheel pattern as the LA engines. Is this true ? I'm looking to mate either a newer 318, or preferrably a 360 motor inplace of the old broken poly. I was planning to rebuild the poly as it is very tired, but the cracks dampened my hopes. Since it is a dump truck, I'd also benefit from the power of the 360. Thanks for any advice you might have for me. I'm looking forward to getting the old girl on the road !

Ryan in NY
 
i think fixing the poly would be a labor of love. my advice is head down to your local dodge dealer and order part #p4510852.and all your problems are solved. (360/320horse).
 
.....sorry not in my budget. I'd be looking for a used/decent running engine from a scrapyard, or the like. I just need to know if it will fit my bellhousing/flywheel or not.

Thanks for the suggestion though.

Ryan
 
OK- I heard from Bob Asay that the pre 1962 (mine is a 1960) poly blocks have a different bell housing pattern.... so today I went to a friends house who is a MOPAR nut. He had a bell housing for a 318/340/360 and it indeed looks different then mine. Now my question is, would it be possible to either find a bell housing that fits my tranny (4 spd 1960 D600 truck tranny) that will fit the 318/340/360, or would it be possible to make an adapter for the bell housing, and a spacer for the flywheel ? I think I'd rather find the right bell housing, as it would be simpler to put together, but I do have access to a decent lathe, if I need it.

Any suggestions ???? Thanks.
Ryan
 
Farmall1938 said:
OK- I heard from Bob Asay that the pre 1962 (mine is a 1960) poly blocks have a different bell housing pattern.... so today I went to a friends house who is a MOPAR nut. He had a bell housing for a 318/340/360 and it indeed looks different then mine. Now my question is, would it be possible to either find a bell housing that fits my tranny (4 spd 1960 D600 truck tranny) that will fit the 318/340/360, or would it be possible to make an adapter for the bell housing, and a spacer for the flywheel ? I think I'd rather find the right bell housing, as it would be simpler to put together, but I do have access to a decent lathe, if I need it.

Any suggestions ???? Thanks.
Ryan
Click to expand...
Talk about a can of worms. If it was me I would find a good 318 and make the adapter and spacer. When I worked for Ma Bell we had a 72 D700 bucket truck with a 318. We mostly used it for towing because you hardly noticed 10,000 pounds of trailer and cable behind it. Power is not an issue with the 318 and a 360 would require you to find an externally balanced flywheel of the right diameter in addition to the proper bellhousing. With the adapter and spacer you could use your current flywheel, clutch, bellhousing and starter. Look for a 72 318 because they have the forged crank and hardened valve seats. You can probably make the parts you need before you find a bellhousing. Just my $.02. Good luck with your project.
 
I have a bell that has side mounts, passenger side hydraulic clutch and both LA and /6 bolt patterns. It would be heavy to ship though it is cast iron. I also have a neutral balanced flywheel( 318 ) these came out of a 1966 Dodge D200 with a 4 speed granny box.
 
I plan to pull the bell housing and flywheel/clutch out of the truck later this afternoon. I want to look at the bolt pattern of the tranny. Hopefully I can find a bell that is closer to me (I'm in NY) so the shipping won't kill me !!! I'm trying to get this thing on the road cheep. I paid $175 for the truck, and I've got 300 + 300 from Dad, into the tubes/tires. Not to mention brakes and lines......etc. Thanks for the help.
 
340- do you have pictures of the bell housing ? I got mine out, and want to compare them..... I need one of the engine side and the tranny side. Thanks alot.
 
340mopar said:
I have a bell that has side mounts, passenger side hydraulic clutch and both LA and /6 bolt patterns. It would be heavy to ship though it is cast iron. I also have a neutral balanced flywheel( 318 ) these came out of a 1966 Dodge D200 with a 4 speed granny box.
Click to expand...
Farmall, if this bellhousing doesn't work out for you, there is an early hemi to LA torqueflite adapter on Ebay, Item number 260007961261. If you look real closely, you will notice that there is no difference in the bellhousing bolt circle. The only difference between the two engines is the length of the crankshaft flange. The early engine bolted the flywheel to the crank flange with nuts and bolts. The LA engine had the bolt holes in the crank flange threaded for the flywheel bolts. This made the LA crank flange 3/4" closer to the block face. I learned this by bolting a 392 to a 727 in a 70 340 Cuda.The early Hemi, the Poly, and the LA all have the same bellhousing pattern. If you want to get your truck on the road for cheap, get a decent 318 and the right flywheel bolts (the LA's are shorter) and drive. You shouldn't even have to change the mounts unless they are shot.
 
<quote>The early Hemi, the Poly, and the LA all have the same bellhousing pattern.</quote>

The pattern on my poly is different then the later polys and LA blocks. I verified this by looking at a SBD bell and it is not the same as mine. Bob Asay also told me that only post-62 poly's are the same as the LA pattern. Mine is pre 62
 
One other place you might look is in heavy equipment. I used to work on forklifts and saw them in bigger Hyster forklifts. They probably were used in Yales too since Yale and Hyster are partner companies. I used to work on a 58 Hyster SC180 regulary that had a Poly 318 in it. Don't know if you have any forklift junkyards around you but if you do that might be a place to check.
 
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