Hello from another new guy, old Dodge guy that drives a 1959 TR3, (pls don't hate)'. I'm also working on my '57 Dodge W200, 4x4, 3/4 ton and trying to get it going. Truck came with a 6 but it's dead. I just found and bought a 1956, Running! Dodge 315 Poly that came out of a 1956 Coronet. After reading all the history of discussions regarding Hemi's and Poly's I can see you guys have a lot of detailed information. So here is the question. Number 1. Can I use 354 Poly heads on the 315 and still get reasonable compression without changing the pistons? Or would it be better to go with the 325 poly heads? (From reading your site I understand Dodge made the 354 engines in Hemi and Poly configuration.) Number 2. Can I use the 4-barrel 354 intake manifold on my 315 engine? Or should I use the intake from a 315 or 325 Dodge engine? Any way thanks for any info or opinion you may have.
No. The Chrysler Hemi and the Dodge Hemi and their respective poly's are totally different animals. Almost the only thing that's the same is the bell housing pattern to the block. Desoto is yet another animal. Chrysler poly can be changed to a hemi with Chrysler parts. Dodge Poly to Dodge Hemi I'm not sure about but they do not interchange between the brands. Dave
I don't know a lot about Mix-n-Match of Hemi parts, but I do know when things don't work to figure out why. I believe this started life as a 55 Hemi and was built by a well-known Hemi/Flathead racer and builder machinist. In this photo it's all new insides and ready to light up and run in (or so I thought). Here's my builder and Friend trying to get things working together so we can run in the Camshaft and do a final tune. That's him messing with the Carb along with 2 other friends. That day was 100% non-successful. It was decided there was a Carb issue that couldn't be overcome that day. Well fast forward a few years and after having a Qualified Carb friend doing his thing I decided to once again try to light it up and run it in. After a couple days of W.T.F. is going on and talking with my different local machinist as well as the guy that ground the camshaft to start with it seemed it was time to do a teardown to get to the bottom of things. Flat Top pistons with Valve reliefs and .125 below deck, more commonly known as Poly Pistons and a head gasket that is .065 thick under a Hemi Head combustion Chamber just doesn't make enough squeeze to make a good Fart. It also only makes around 7 inches of cranking manifold Vacc and that won't suck fuel in the cyl's without manually closing the Choke to even wet the plugs. I had had enough, and My decision was to buy a different motor. My advice is this, if you're going to start mixing parts together that aren't designed to work together, you better know what you're doing. I thought I "had" the right Guy that "had" all the right information. Turnes out I only got Had!
Hemi and Poly valve reliefs are slightly different Hemis are straight across poly are a little offset.
You didn't say if you measured out what C/R you have. The 241 Dodge hemi was rated @ 7/7.1:1 but one measured out at an actual 6.19:1. Low-po lo-comp truck engines have been found with poly pistons in hemis & hemi pistons in Polys. Apparently with a low-po cam there wasn't any interference. Obviously should have put up the $ and bought hemi pistons.
@Michael W. and @Pist-n-Broke ….Well, where to start. And, I can only probably take you part of the way there. @73RR is probably still on the HAMB and VERY knowledgeable. Perhaps he will see this thread and clarify for us. In any case, for all three brands there are different block sizes, and I mean overall size, not just cubic inches. Within a make, say Chrysler for example, there are low deck and high deck blocks, depending on the cubic inch displacement they were built to be. The same can be said for Dodge and DeSoto engines in that regard. And all were built in both hemi and poly configurations. Generally, a poly head or hemi head will fit on either a low deck or high deck blocks of it’s particular make. The deck height, however, creates manifold fitment considerations. With a few exceptions, low deck blocks require low deck intake manifolds and same goes for high decks. The manifolds do fit both poly and hemi heads. For Chrysler engines of ‘51 thru ‘58, the 331, 301 and 354 are considered ‘low deck’ blocks. Only the 392 block is high deck. One quirk here though. The 392 Chrysler hemi heads were designed and cast to fit a high deck block but use the low deck block sized intake manifold. The 392 heads have extra material on the intake port flanges and it is shaped to fill the space that would be vacant unless a different manifold was designed. Now, one more quirk. That head port mounting surface doesn’t flow as well as the 331/354 heads. So, many racers have used ‘55/56 331/354 heads on the 392 block but spacers were made to fill the resulting gap and still flowed better than stock 392 heads. In all cases, to the best of my knowledge, pistons must match the head design being used. Dodge V8 engine were introduced to the public in 1953. All passenger models that were fitted with a V8 got 241 cu in hemi heads through 1954 cars. At some point in that era Dodge began building some truck engines with hemi heads and also with poly heads. 1955 model Dodge passenger cars got 270 poly or 270 hemi engines, depending on the model and options selected. In 1956 Dodge passenger models, the standard V8 was a 270 poly. Optional was a 315 poly and 315 hemi (D-500). 1957 Dodge passenger got 325 (aka “326”) poly and D-500 325 hemi V8. The 241 thru 270 were low deck, the 315/325 were high deck. Another quirk….1957 DeSoto poly V8 was the same engine as used in the ‘57 Dodge. The only ‘crossover’ I can recall between Dodge and DeSoto V8 engines. DeSoto began hemi V8 production in 1952 models with a 276” engine…carried over into 1954 models as well. For 1955, DeSoto built 291 cubic inch poly and hemi V8s. Considered low deck blocks. 1956 DeSoto offered 341 and 345 cubic inch hemi V8s in higher performance configurations and were high deck engines as I recall. Plymouth finally got a V8 engine for the first time in 1955 models. A 241” poly that was essentially the 241” Dodge pickup engine. 1956 saw additional V8 models offered in 277” and 301 inch poly models as I recall. Never a hemi offered stock in a Plymouth until years later when the second gen 426 hemis appeared. There are also some camshaft cautions about which I am less confident of my recall. I believe there is a difference in lobe spacing between poly and hemi versions and/or low deck high deck due to geometry differences. That question will have to be researched for clarity. I apologize in advance if there are egregious errors in the foregoing information. Blame it on age, mine of course, not yours…. Ray p.s. I forgot to mention the use of Chrysler hemis in some production Dodge cars and trucks. Dodge trucks were equipped with heavy duty versions of Chrysler 354 engines in there larger commercial lines, not pickups. So far as I know that was from about 1956 thru 1958 and I ‘think’ another year or two. Also, medium duty trucks were fitted with Power Giant 315” hemis. I have one of those. Dodge also used a version of the 354 hemi V8 in at least 1957 D-501 models built for racing. Arnie “The Farmer” Beswick raced a ‘57 D-501 post 2 dr at the drags with considerable success, but did switch to Pontiac sometime after. Later I had the privilege of seeing that car (then owned by a collector) at a Chrysler products show in the suburbs of Chicago sometime back in the ‘80s. Beefed up suspension and brakes and the 354 ‘Dodge’ engine with a manual 3 speed transmission. Strictly business.
If that is all that is wrong a set of pistons must cost less than a whole engine. Of course you don't know what else he messed up until you tear the engine down.
Well, Ray certainly filled in alot of blanks and his typing skills are far better than mine. Basically, use Dodge parts on Dodges. No, the Dodge truck 331 and 354 are Chrysler. Sorry to hear of Wizzards problems. Curious what is found in a tear-down.
And if you can put 331/354 hemi heads on a 392 there's no reason why you couldn't put 331/354 Poly heads on a 392...
[QUOTE="Hnstray, post: In all cases, to the best of my knowledge, pistons must match the head design being used. [/QUOTE] There's a lot more to the Hemi game than using parts that fit together. In my case all my pal Earl had to do was a simple C.C. job if he had any doubt. I know he wasn't doing his first Min-n-Match build and had blind faith in his ability to do tis right. I didn't set a budget or tell him what to use or not to us. Yes, HEATHEN I believe it's down there around 4.5 to 5 to one compression. Even is top shape this little C.I. motor won't do the job I want done. That's the main reason I moved on. The little 270 motor will be just fine in a Roadster or a T but not in my Highway driving Truck. I felt the new 57 355ci will be a much better final unit.
1955 Chrysler Windsor model had a 300” non hemi that would accept 331-354-392 hemi’s heads. They were very very popular with Bonneville race cars. I don’t anything about the other polys but knew that the Windsor 300’s was the holy grail to a lot of LSR guys and they would search them out….They were actually 299.3” but guys I knew called them 300’s. The class limit was 305 so they wanted standard bore only. Wikipedia lists all the Chrysler engines and as far as I know 1955 Windsor model was the only one to use this engine and I was 1 year only for Chryslers. Maybe other MOPAR cars used them….I don’t know.
The '55 Windsor engine was labeled as a 301, haven't checked measurements to see if it was actually something else, and yes it was 1 year only. Like the 350: The Chevy is 349 & the Pontiac is 354.... For some reason the 259 Poly, converted to hemi, is often called a 260 for some reason, which is a Ford size...
Just to directly answer your questions, the 354 (Chrysler) parts will not work with your 315 (Dodge) at all. The 354 Poly and 354 Hemi engines found in 1-ton and larger ‘57-59 trucks are actually Chrysler-based, though sold new in Dodge trucks. It’s a little confusing. Heads from a 325 Dodge Poly will work with your 315, though chamber cc may be slightly different. Heads from a 315/325 Dodge Hemi will also fit on your 315 Poly short block but as mentioned above will have unacceptable low compression and valve reliefs in the wrong spot. You’ll need to get the correct domed Hemi pistons for that, but it’s straightforward. If you want a factory 4-barrel intake manifold for your tall-deck Dodge, it will be a hunt. Only the ‘56-57 D500 intake will work. It won’t matter if it’s a ‘56 315 Poly or 315 Hemi, or a ‘57 325 Hemi. They all interchange. The carburetor pattern is small WCFB. If you want something flashier, there are a few aftermarket 3x2 and 2x4 intakes for the tall-deck Dodge, and maybe a 6x2 log manifold would look cool too.
My friend Earl was a well-seasoned Mopar guy all the way around. He knew this, and/or new where to find the info as well as knew how to check the c.r. before bolting the heads on. I never had any reason to question any of that. The sad ending for him is that he's in a full care facility with deep seated C.R.S. It's been terrible to watch.
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