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Re: can somebody tell me about my 325?

From: Hank Dozier
Date: March 28, 2002


OK.....Here is the long answer. The poly and the hemi for the Dodge shared their intakes. Therefore you are correct in the assumption that it fits both heads. That said, here is what I recommend for a hemi conversion. You will need heads (get casting numbers 1734049-1, 56 D500/500-1, or 1828129-1, 57 KD500 and 57-59 Dodge truck) These are the large valve/large port heads, but will need exhaust valve inserts installed if not already done. I guess price at about $375 to $425/pair for the 1828129 number, more for the other since lower volume and RARE) You will need the rocker assemblies from ANY 241-325 hemi, and the head bolts. You should be able to pick up a core rocker assembly set for about $150.00 Head bolts will cost you about $30.00, but see if you can get them as part of a deal on other stuff. Pushrods will need to be NRS. Walker has them for about $160.00 in Chrome Moly large tube. Get adjustable, as you will find that you need that anyway with stackup tolerances or decking you do. The other more expensive way is to get the pudshrods non-adjustible and convert the rocker arms to 426 adjusters. Big bucks. Recommend against it. Use a hydraulic cam, and set the pushrods for half travel on a dry lifter at trail assembly time. Exhaust manifolds are hard to find. Period. Go with fabricated headers. Header flanges for under $40.00 might still be available from a guy I know in Newport Beach, CA. Send me an email, and I will give you his email name to contact. Pistons....You CAN use your poly pistons with hemi heads. They are close enough. You will get about 9.25:1 CR at stock bore. Otherwise, Ross forged at about $800.00/set and ANY CR you want. Cam...My remarks from earlier correspondence still hold true. The Polys and Hemis both like the same type of cam event/lift. The hemi just breathes a little more at low lift. Timing set...true double roller Cloyes type. If you keep your fuel pump, you might need to narrow the upper cam gear slightly to get enough key protrusion to capture the eccentric. Beyond that, all other parts fit. You might need to detail your timing for the hemi slightly, but not much.


Last changed: July 19, 2018