I found a guy selling a 57 Chrysler 354 Poly engine. I was wondering what some of your opinions were on this engine. I don't know anything about them really so I need some help on it. I have read on here that you can switch the heads out to change it to a regular Hemi which would be cool. I also have another question: I know a guy who has a set of early Hemi heads but I am not sure which ones they are (331, 354, 392). How can I tell the difference between them and identify the heads? Thanks for all the help and opinions.
Johnny, You need the 'Complete Chrysler Hemi Manual' by Tex Smith & Ron Ceridono. The book isn't perfect. But it is better than some opinions you may get here. Get the book, it will be $$$ well spent. The poly 354 can be made into a hemi easily. There is a lot to explain. The earliest heads, the one's with round exhaust ports are usually not used, few people like them. The 54-56 heads are prefered. They have oval exhaust ports. Some have water outlets in the front of the head some don't. The 392 heads will not work unless you use log intake manifolds. The book explains all of this, has casting #'s & much more. You may pm me if you have more questions. Good Luck. Lucky667
Also put "hemi tech index" in search & start reading. Hemis are getting common enough that some are going to keep the Poly heads on thiers!
the hemi heads fit but the upper notch for the upper set of pushrods is barely covered. I recommended a slight bit of weld and resurface the block . They are just borderline and may or may not leak. if it was mine it would so I would take an hour and elimnate the chance. Don
Nothing wrong with the Spitfire engine. The Hemi intake manifold fits so if you need a 4-bbl there are plenty available and if you bore out the holes to match a Holley gasket then you have a really good dual plane intake. IMO it is perfect for a driver, lots of low speed torque. Pm if ya like. .
I'm with George and 73RR - be different and leave it as a poly. My 1958 4bbl 354 poly is rated at 310 hp - the same year 4bbl hemi rates 345 hp. You'll save a bundle of $$$ and only give away 35 hp. I'm figuring you'll pay $100 per hp if you try to do the hemi conversion. You'll probably have to notch or swap out the pistons as there are invariably valve clearance issues. Besides polys look kinda cool with their scalloped valve covers. My $0.02
Thanks guys for the help. I will most likely leave it a Poly if I get it due to money (I don't have enough). It is a sweet looking motor based on that pic. I haven't ever seen one. I will take a look at some of the books to get some more info. Can't ever know enough. 73RR I would like to know more about your motor and what you have done to it. The one I am looking at is not suppose to be stuck and is all original. It also comes with two original auto transmissions. Any good or bad things on the transmissions?
There is a simple reason that myself and a dozen other companies make trans adapters for these engines. The stock piece may be fine in a restored car but the cost to rebuild is quite high and compared to a A-518, well, there is no comparison. If nothing else, the late torqueflite is 100 lbs lighter. The Spitfire is an excellent engine but lacks the 'cool' factor of the Hemi. As has been said, it may be similar in cost to a Hemi to rebuild as it uses many of the same parts as a 354 Hemi. The biggest parts issue will be getting good pistons so budget for some Ross pieces. There are no ready made headers for this engine but flanges are available so you can modify a set (designed for something else) for your project......now tell us what you're working on! Is the engine going into the avitar pu?? .
The engine would be going in a 28 Dodge Coupe that I just picked up. It is just the body so I am going to build a frame for it. The guy who had the coupe cut the top off but thank goodness didn't do any more. The cut line looks like a blind man did it but I can fix it and chop the top at the same time. I have a Ford 4-speed toploader trans layin around. Do they make an adapter for a Ford 4-speed? It would save me some money.
Jeesh, this may be a cold thread, but it's new Poly info to me. I've always been in love with Hemis, but I'm really starting to DIG the Polys, man.
The Jalopy Journal
