Spitfire/HEMI Project.


Yup, I fell off the wagon. After a year and a half of not having a project I pulled the trigger on a new one. Rebuilding the Tri-Power off the 57 and my kind of offhand remark about building a Poly lit a fire under me.

I made a deal on a basket case 331 Hemi from a 1955 Imperial and a couple of pair of 301 Poly (Spitfire) heads and misc parts. The Hemi parts consist of a block and main caps......still in the car bolted to the transmission (I'll be picking that up in the next week or so). A crank .010/.010 ........ it had been turned, oiled and wrapped in plastic then set in the trunk for 40 years and yes moisture got to it and it will need to be turned again. The pistons and rods are junk, somehow 6 of the rod caps walked away over the years, but as Dave decided to go with H beam rods in his HEMI I have access to a good stock set. I was really pleased to find out the heads were the "triple nickel" (555) heads which are supposed to be the best flowing stock ones. I also ended up with 2 pairs of rocker shafts and the exhaust manifolds.

The Poly parts pile consists of 2 pair heads with rockers, valve covers, 2 valley pans, distributors and I was supposed to get the exhaust manifolds.

Basically what I ended up with is the adult version of the engine parts you'd find in an old AMT 3 in 1 model..........yes if you understand that reference you are old.

Did I mention the Poly heads were still attached to a couple of donor 55 Windsors? After about 10AM we've been having T Shirt weather here (that's supposed to come to a screeching halt Friday) so I spent the last couple of afternoons in one of my favorite places.....a local wrecking yard.


YJ2 by M Patterson, on Flickr



This is one of the donor cars, the lower quarters were sacrificed for a 55 300 decades ago.


YJ1 by M Patterson, on Flickr


And this is the pile of Poly parts I hauled home. I couldn't get to the exhaust pipes to get the manifolds off....which may not be all bad, It gives me an excuse to pull the trigger on a pair of Spitfire header flanges I came across


YJ3 by M Patterson, on Flickr



The first step of course is to get everything cleaned up and see what I have to work with. The short block will be pretty straight forward and I plan on using stock crank and rods and probably going .060 over..... however depending on how the block sonic checks, going clear out to 3.9375 (354 CI) is not out of the question. The cost on a roller cam and lifters has come down quite a bit in the last 15 years so that's on the growing Hot Heads parts list.


As far as the heads I'll actually be doing a pair of the Poly heads and the HEMI heads at the same time. Chrysler Poly (301-331-354) information is a bit scarce, but from what I can tell the Spitfire heads are pretty much the same except the 55 301- 56 331 two barrel used smaller valves than the 56 331 four barrel and 57-58 354. I'll be opening up the heads I have for the bigger valves which I ordered this morning.


The plan is to do the initial assembly, test stand and eventually install the engine in a car in the Poly/Tri Power configuration. Depending on how well it performs (or how long it takes me to want to experiment further) I'll have the HEMI heads ready to bolt on.

I'm building the engine with an eye on it being backed with a 518/46RH overdrive automatic and a 4.10 rear end and eventually going into a 3000-3500 pound car.


I'm also looking into eventually pulling the Tri-Power and going with a single 4 barrel manifold and something like FITECHs GO EFI 4 system. Yeah, kicking and screaming into the 21st century




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