I am building a Chrysler 354 Poly motor for a friend, and am having issues with finding a second good head. Out of four, three have failed pressure testing. Evidently there is a thin spot in the castings in the center exhaust ports which is prone to failure. The back story: A fellow named Howard had a '34 Plymouth for decades, and reached the age where he was no longer able to build the dream car he wanted. Through a series of what the new owner calls "weird cir***stances", he was given the car. A portmanteau of "weird cir***stances" and "Howard" have become the car's new name. "Howeird". Hence the desire to use unusual components in the build. Very few people will be able to identify the engine at a glance, because it's a small community that will recognize an early Poly. So on to the question which would make this even more weird. Given the difficulty of finding good Poly heads vs good Hemi heads (I have Hemi heads laying around) would a Poly head on one bank and Hemi on the other be feasible? The Poly and Hemi blocks are the same, and interchangeable. Heads bolt on, camshafts, lifters, etc. are the same. It would require Hemi pistons on one side and Poly on the other. I need to have custom Poly pistons made anyway, so I could make the compression ratios and piston weight per side very close to the same. Weird, eh? Thoughts? Or if any of you have some good Poly heads somewhere, preferably in the midwest, hit me up.
I actually had similar thoughts. I'd put it in a split hood 46-48 Dodge, Take it to the Nationals in Louisville. Have one side hood open one day, the other side the next! Best I can tell thinking about it was balancing the rotating ***embly and weather the cam would work for both heads.. If the hemi & poly pistons weigh about the same it should be able to match them up. No idea on the cam. Intakes interchange so that should be no problem. You didn't say which Poly. Only hemi based polys can be converted, not the "A" Polys.
I am waiting for more information on this. Will be a good read. in the mean time, have a great Thanksgiving!
Is it a Dodge poly or Chrysler? The 31' Chrysler coupe I'm building will have a 57' Chrysler 354 Poly. I have a set of 301 Chrysler poly heads. Don't remember the condition, been years since I looked at them
Okay, it's a mental exercise of weird. I get it. But if you are doing stuff just to be different, you gotta stick a Fluid Drive behind it, you know a clutch and hydraulic bellhousing. Oh, and that 2door/4door that was posted? That too. Gotta shove in a Vee drive and a FWD setup. Might as well make it center drive, so it's off for left and right hand drive people. Take the Munstermobile serious and have a solid roof in the middle and a folding top in back. We have had 3 wheelers for almost a century, but most are one axle and a single front or rear. Build it so it's like a bike with a sidecar!
1957 354 Chrysler Poly Then it wouldn't be weird. Chrysler 354. Take a peek at those 301 heads if you can, and let me know if they look reasonable. The fellow I'm building it for is based in Mitchell SD, so Bismark isn't beyond the limits of a one day round trip.
I personally think it's a dumb idea, especially when you have to replace 4 pistons and all the problems that entails. Either find a good poly head or go hemi all the way. Rat Rods have weirdness points, traditional Hot Rods don't.
From what I recall the 301 poly heads are not interchangeable to a 354 Poly. Putting hemi heads on the 354 Poly, while achievable will require a piston change.
Bore difference is .311 so they might/might not clear, but will bolt on where the 301 "A" poly won't bolt on.
The Jalopy Journal
