As the title says, I just bought a 1958 Dodge Coronet 2dr hardtop with a rebuilt 325 poly in it. I intend to put in a low mileage 383 I have in it but the original 325 motor is there and my son wants to keep it in case we ever do a early hot rod. I know that hemi heads will fit this block and was wondering what heads I need to look for as there is so many different early hemi heads that were different from chrysler, dodge desoto, and plymout? I assume that outside of pistons the short block can remain the same or can I use the poly pistons also? Thanks for all the info guys.
Plymouth of the 50's never was invited to use a hemi. My guess is that you would want to use 315 Red Ram or 350 Hemi heads, etc. Depending on what the pistons look like I would think you could stick with poly pistons, as long as there is enough clearance for valves. One important thing would be to make sure that water and oil passages are all accounted for between head and block.
The 315/325 Dodge heads are best, 241 & 270 less so. You'd need to change the complete head assembly inc push rods & ex mans. Intakes interchange. Pistons might or might not.
I believe you'll need high deck Dodge heads... 315/325. Using the low deck heads would require using an adapter for the intake or you'd have to fab your own.
I've always been told that your motor will only take the 315/325 Dodge Red Ram heads. The intakes will interchange but the exhaust manifolds will not, and you can't use the poly pistons with the hemi heads. I've never actually done it, but that's what I heard.
Several random thoughts....what is the ID on the block?? ya see, unless you have a verrrrrry early 58, as in mid 57, the 325 was not used by the factory. The 58 was offered with the A series engine (277, 301, 303, 318, 326) or the, new for 58, the B series 350. The easy way to determine which engine group you have is whether or not the intake has an air gap with valley cover (early Hemi/Poly), Air gap without removeable valley cover (B) or if the intake seals all the way around (A). If your engine ID is 'KDS' then you're in luck with the head swap plan. Keep in mind that the the B-RB engine will not bolt-up to the existing trans so the long list of 'things I gotta change' starts here. .
Its not a b engine, it is definitly a poly. Car was built in Dec of 58. Its a poly but it isn't the poly that the plymouths had.
As I said earlier, 315/325 heads are best, but you can use 241/270 heads. Sealing @ the top of the 241 heads are marginal when used on a high deck. High deck intakes fit regardless of heads used.
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