Hot Rods 315 Hemi questions

I got some engines out of an old farm shop. One of them is a 315 Hemi with the crank, rod and main caps missing. Give me the short version of using the heads on a poly. I know where there's a poly pulled from a low mile wrecked 56 Dodge. Am I correct the heads would fit it and all else I need to swap is the pistons (assuming mine are good) Do the cams and timing set interchange?
Option 2 is the "what's it worth" question. thanks

 

Yes the heads bolt on. However, there has been some discussion about the pushrods bores on the poly block needing to be "clearanced" when using hemi heads. I do not know if that is factual or not. Your are correct about needing hemi pistons as they have valve clearance eyebrow shaped machined into their domes. So do Polys, but the positioning is not quite the same,especially on one of them.

The cams will interchange....that is, the block is the same...but as I recall, one must use a hemi cam for correct valve timing as the lobes are indexed differently.

Is the '56 Dodge engine also a 315? (might be a 270)

Ray

 

Thanks. I'm not sure on the engine size. How would I tell? It did come out of a pretty fancy sedan with automatic tranny, I parted out it it's remains a few years back. Since I mostly play with Fords, the 50s Mopar engine variations gets a bit dizzying. Will the 315 heads fit the 270? As I understand it, there is the low deck/tall deck thing. I was thinking if I found another 315 and both were good standard bore, I might be able to use the pistons and build a hemi on the cheap for my crusty 36 Ford coupe.

 

You will need the complete valve train from the hemi cams are the same as long as both engines are 315s or 325s. 241 and 270 cams won't work The Hemi pistons have valve notches straight across from each other polys are a little off set other than that they are the same. Intake manifolds are the same. Head swap to a 270 will work except pushrods.

 

Put "Hemi Tech Index" in search & start reading! All of the Dodge Hemi heads will interchange, differences in valve sizes, but they will work. The high/low deck thing involves the cams, high & low don't interchange. Too bad the WebRodder site is inop, had a good 315 build on there.

 

Also, as to what you have, there should be a use code on a flat in front of the valley cover. post it we'll see what it is.

 

Post the numbers on the heads too. If you change your mind n decide not build it, send me a pm I'd be interested in the 315 tall block parts.

 

be carefully....in 1956 they came out with the for runner of the 318 poly.....early Dodge hemi heads will not work on them...go to the Hemi tech forum on here.....if the engine has a valley pan then that is the tell tale worker bee....if the intake sits flush with the heads then it's a no go......

 

I'd have to get out to that farmers barn and check out the poly. I'm only assuming the hemi is a 315 because it says that on the valve covers.

 

Does it say "Power Giant" on the hemi valve covers? That's what the Dodge truck engines were called....

As stated by others above, the poly engine can be identified by the code stamped into the block. It is stamped on the passenger side, top of block, just in front of the tin valley cover. That is the area behind the water pump and in front of the intake manifold.

If the poly was in fact originally installed in a '56 Dodge car, it should be the 'early' poly and be compatible with your intended use. However, it could be either a 270 or 315, as both were used in '56 models. To the best of my recollection, the 'new' style poly was first used in '56 Plymouth only, in 277 and 303 (301 ?) displacement, not in Dodges at that time.

Ray

 

I believe the Poly engines had the pushrod holes elongated for clearance, the Hemi didn't need it done, so either block will work with hemi heads.

 

Is there any difference in the truck engines?

 

Not so much on Dodge as Chrysler. The water pump is often mounted a bit higher. Maybe the valve stems are sodium filled. I have a Power Giant 315, bought from a farmer's storage shed. Been sitting on the ground for a long while. Looked good from the outside. I could not believe my eyes when I (tried to) pull it apart. Enormous amount of rodent infestation had occurred over the years.

Finally got it apart. Needed pistons cause I had to drive them out with BFH, rods too, because of advanced rust from rodent urine. The real damage was pretty much confined to the lower end, but the crank cleaned up. In the end it was a rebuildable core, but certainly not worth anywhere near what I paid for it when it was found. Oh well

Ray

 

To recap some of the info:
•All Dodge heads swap around, Hemi to Poly, but you need all of the Hemi related parts.
•Intake manifolds do not swap between short deck (241-260-270) and tall deck (315-325).
•Camshafts do not swap between short deck (241-260-270) and tall deck (315-325). Yes, they physically fit, but you will not like the way they work...
•Dodge used Dodge Poly engines (EarlyHemi style), as opposed to Plymouth Poly engines (A series 277-301-303-313-318-326).
•Use codes, stamped on the block, are here.

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