Thread: Spitfire / Hemi build

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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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Very cool Mike! That sure didn't take long. That salvage yard looks to have some nice stuff in it. If you happen to see a bed side tool box door on a 67-72 chevy, I could use one pretty bad.

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If I was in the neighborhood I'd be out there with you, old junkyards are one of my favorite places in the world.

I thought you were going to put a hemi in a triumph spitfire, like the hemi sprite build https://www.gregspradlin.com/custom-...9-hemi-sprite/

I could probably make the HEMI fit in the car, I'm just not sure I could make me fit in it.



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That motor sounds fun to build and please never show me pictures of your perfectly preserved, mummified, Arizona " junkyard " cars again. I was checking for rust on a 2013 today lol

".....That motor sounds fun to build and please never show me pictures of your perfectly preserved, mummified, Arizona " junkyard " cars again. I was checking for rust on a 2013 today ......"

You did catch my "T shirt weather" comment too didn't you Seth Only took me one trip back to Illinois in January a couple of years ago to remind me why I live here.

I am looking forward to this build. There are several thing I want to try that I have been wondering about, basically comparing "what looks good on paper" against real world results.

The first one I'm wondering about is using Citric Acid to de-rust the block and heads. I've used it before things like my Granddads rusty old tools and was impressed. I want to see how it works on rusty water jackets and the other areas you can't get into.

I'm also real curious about how much HP difference there is between the HEMI and POLY heads. When you go back and look at the difference in say the 57 354 Poly and compare it to the 56 354 Hemi the difference is not that great.....310 HP/405 Torque for the top of the line single 4 BBL 57 Poly and 340 HP/385 Torque for the 56 dual quad solid lifter 354 Chrysler 300B engine.

I'm also wondering what I'll see performance wise going to a roller cam compared to the older designs I'm running in the 57 Plymouth and 37 Dodge.

Right now I'm looking at the initial configuration being as a Poly with Tri-Power and then switching over to Fuel injection. The next step will be switching over to the HEMI heads with fuel injection......I'll probably not bother checking carburetors against the fuel injection with the Hemi configuration as I pretty much already know that a 331 and 354 carbureted engine runs like.

Not sure exactly how I'm going to test the combinations......I want to do a little better than the old seat of the pants thing and I don't really want to go thru the dragging the engine back and forth to the engine Dyno in Tucson. My other 2 options once I get the engine in a car are putting it on a chassis Dyno (my friend who runs a local speed shop usually brings the portable chassis Dyno to his shop twice a year). Though not as accurate, taking it to Tucson Dragway a few times for testing also has a certain appeal.

Anyway that's all tire kicking until I get the engine put together.



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Originally Posted by Mike P

I could probably make the HEMI fit in the car, I'm just not sure I could make me fit in it.



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Aw heck, you'd fit with room leftover! A hemi in a Spitfire would be so far beyond kewl I can't even comprehend just how kewl it would be! Come on Mike, I dare ya!!!!!!!

I had a friend when I was stationed in Germany back in 77-79 who would occasionally loan me his Spitfire......what a ball it handled like it was on rails (lot of fun on some of those narrow German streets). Not sure, but I kind of think hanging a 700 pound blob of HEMI over the front tires might affect the handling just a wee bit......sure would be fun on the Autobahn though

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If you ever grow tired of those triple nickel heads, keep me in mind. I wouldn't mind getting a set for mine. And Seth, please go back to AZ and get another cool car. I might need another project in 10 years or so.

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Ryan the triple nickles were pretty standard on the 55 331s and as I understand it early 56 354s. That being said from 54 on (when they enlarged the ports and valves) IMO there really wasn't such a thing as a bad HEMI head.

I don't know that you'd really notice any difference between the heads on a street driven car unless you're really winding it up........Super/Turbo charging would probably be a different story.

Of course you would get bragging rights, but only the hardcore Mopar guys would know what you're talking about.


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[QUOTE=

Of course you would get bragging rights, but only the hardcore Mopar guys would know what you're talking about.


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Mike, I found out a long while back, there are Mopar fans, and there are Hemi fans also, I am both but I have not found many non Hemi fan as of yet, most seem to like it know matter what brand they favor. I believe they are one of the best looking motors out there, the only reason more people don't run them more is there size, and the budget i takes to go along building them, the 392 roller rockers I just purchased literally could buy a crate SBC!
I think a Spitfire build will be great, something neat and unusual to see. I look forward to seeing your build.

Mopar has fewer builders because the parts are pri$ey.

You are absolutely correct Firebird, Mopars have always had a high price of admission. As far as building a Hemi (1st or Second Gen) there is no way around digging deep to do it. Matt was being quite literal with his roller rocker comment.

Matt I totally agree about the looks of HEMI. Even to the novice car guy who doesn’t know what a HEMI looks like they are visually an IMPRESSIVE looking engine.. …. to the HEMI owners out there, how many times have you heard the “so that’s what a HEMI looks like” comment?

I had recently come across this video of a 57 Plymouth and I guess it was in the back of my mind when I made my bragging rights comment. I’d followed the build of this car on another site. It started life as one of the 2000 or so 57 business coupes (6 cy, stationary back windows and no rear seat) Plymouth built in 57. It’s got a 55 331 and 4 speed and the guy did a beautiful job on it, I’d love to see it in person.

I think we’ve all come across “this guy” at a car event .

https://www.youtube.com/watch?v=bdhr6UeDd7I


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We need to fly that guy up here and have him walk around my Vette. I can only imagine what he would say then. LMAO! That was a very nice car and the father and son did and amazing job on it.

Matt, where are the pics and update son the new car let alone eye candy elephant part pics? Have you had any luck on your other project we have been talking about?

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