Chrysler Windsor 301 hemi/poly motor - Can you put on Hemi Heads?

I saw an ad for a 1955 Chrysler Windsor 301 hemi/poly motor w 2bbl carb with 66k miles on it. Ad states you can switch out the 301 heads and put any early Chrysler heads and rockers such as the 331, 354 and 392, its the same block. This doesn't seem correct to me? Can you help me out?

 

The Chrysler poly is the same block, although the bore is a tad smaller to get that 301 - a 301 is perfectly square at 3.625 x 3.625, a 331 is 3.81 x 3.63.

It can be done; a friend has some old hodgepodge of parts built into a mud truck he picked up downstate that appears at first glance to have a Dodge hemi in it. But the block number on it comes back as '55 Plymouth.

Normally to convert a Poly to a Hemi requires a piston swap as well. Which, on a 66K motor, unless it's burning oil bad you may as well run another 40,000 out of it before you tear it down.

 

You would want 331 heads or you'll have a very low cr. Many "D" motor Bonneville cars are built with just this combination.

 

Thanks!

 

thats good to know...

 

I'm pretty sure the Dodge and Plymouth Poly engines require Dodge Hemi heads to work. The only Polys that accept Chrysler 331-354-392 heads would be a Chrysler Poly.

Someone correct me if I'm wrong..

 

The Hemi pistons have valve reliefs opposite each other, the Polys have offset reliefs. You would have to see about custom pistons. There have been reports of some poly blocks not having clearance for the push rods where they go through the block, but don't know if talking OEM or fatter aftermarket pushrods.

 

Being here at work, I don't have my manuals handy....but I do believe you are correct.

 

Any reason you don't want to run it as is? Just curious. You KNOW I love Hemis. Just don't see too many people leaving the Poly engines alone for some reason. I think they're pretty neat looking, personally. Not sure about parts availability or performance characteristics though...

This one is super nice looking!

 

Dodge, Plymouth & DeSoto Polys all use Dodge heads, Chr uses Chr.

 

Don't use 392 heads, too many problems. Best would be the ever popular & expensive, hard to get '55 331 heads, followed by the '54 331 heads & intake. Considering the smaller bore, there may be advantages to using the smaller valve 51-3 heads port matched to a '54 4 bl intake. The 51-3 heads are considered "less desirable" so they are cheaper than the later heads. The '56 354 heads are good heads, but may have valve/bore clearance problems on a 301.

 

i have weiand blower manifold that suits poly engine, have it sitting on my 301 poly

 

Actually -

Chrysler Hemis are all their own, and share blocks with other Chrysler motors only, through '58, 331-354-392.

DeSoto hemis are all their own, and that I know of only came as a Hemi through '57, no poly variant.

Dodge Hemis are again all their own and have a poly variant, 241, 270 and 325 - but it seems the 1955 Plymouths (ONLY) also used the same basic block, including in a Plymouth-only displacement. This block was used through '59 (as a 326) although the Hemi variant went away after '57, replaced by the wedge 361/383 that was shared with DeSoto, and eventually available in high end Plymouths (59 or 60) and low end Chryslers (1961-on).

Plymouths never came factory with a Hemi prior to the creation of the 426 in the 1960s. They got their own V8 block in '56 which grew into the earliest version of the 318.

And this is pretty much a US-only list, Canada and export cars got some strange export only configurations to match the strange cars like Plymouths badged as Dodges (with or without Dodge nose) and trucks badged as DeSotos.

That's why my friend's truck is so odd, it's on an M43 frame (Dodge military like 2 ton 4x4) so the Mopar motor was probably a bolt in, but even though it's obviously a Hemi the block serial looks up as '55 Plymouth car, with no way to know if it's a 241 or a ... 260 I think, the weird one year only displacement. It runs, though, so whatever's inside must clear the valves and so on.

Now the question is why the hell did someone bump a thread from September 2007 with a post that doesn't have much of anything to even do with the topic?

 

Dodge Hemis are again all their own and have a poly variant, 241, 270 and 325
Also 315.
- but it seems the 1955 Plymouths (ONLY) also used the same basic block, including in a Plymouth-only displacement.
That's the 259 (a.k.a. 260).

This block was used through '59 (as a 326)
Nope - that's a poly A derived from the 318 etc. - 1959 Dodge only.

 

You can run 354 heads on a chrys. poly block. you just have to chamfer the top of the cylinders to clear the valves.

 

Didn't the Markley Brothers run a 315 inch (?) Plymouth poly block with Dodge heads in their Bonneville lakester? Because of the odd combination they had to fabricate a steel blower manifold for the engine.

 

to answer your question, yes you can run any of the Chrysler 331, 354, 392 heads on your 301 ploy block. As stated all chrysler blocks have the same bore spacing and head bolt pattern shared between polys and hemis. the pistons were all flat tops except for the 300 series engines, some marine variants, and factory performance based engines that had domes. the valve reliefs won't make a difference between the two but the cams are different.

all the heads differ in valve size, port volume, and chamber cc. the Desoto were different bore spacing to include the dodges. the dodge family of engines though will interchange from poly to hemi like the Chryslers, Desoto is on there own



Sent from my SM-G900V using The H.A.M.B. mobile app

 

If the 301 was an underbored 331 block you could bore it .185" and use stock 331 pistons. Then use the early 331 heads which are the cheapest to buy. You can get over 1 HP per cubic inch with minimal modifications. This would be a cool engine for a street rod, the only drawback would be, the small block displacement with big block weight.

The advantage over an early 331 would be that the block has a normal trans interface not the extended block of the early Fluid Drive models.

It would be a fun project if you could get it cheap. Unfortunately the kind of moron who would swap out a 66,000 mile Chrysler V8 for a junkyard Chev 350, probably wants a fortune.

 

No. They used a 259 Plymouth block with Dodge hemi heads to run in "E" class. (260 cid max). That was at first. Then they went to DeSoto engines

 

Chrysler Canada never got their own V8 manufacturing facility until 1956. Then they got the engine best known as the A motor or wide block 318. They made some odd versions of the 318 A motor. Including a 303 cu in version for Dodge and Chrysler in 1956. This was larger than any A motor in the US, which is why it was chosen for the 1956 Plymouth Fury. This engine was used in that year, in the US in Fury only, and in Canadian made Dodges and Chryslers. I believe there was a 301 cu in A motor although, this was probably the same 303 they just called it a 301 to be in line with US products. There were also 313s and 315s as well as 318s.

 

You could use a stock 4 barrel intake from a hemi on the poly or, use the 55 hemi heads , use the head bolts, push rods, cam. I have all the parts to make a 301 hemi, what stopped me are questions about chamfering the bore and piston valve reliefs.

 

Here is a pic of a 325 Poly (Dodge).
(Chrysler)I wouldn't try the 392 heads on it. Its a tall block. The 331 or 354 heads should work with a little work as stated earlier by others. The early 331 heads are cheap but the 4v with wet intake (built in thermostat) on the 51-53 usually more expensive or the cross over kit also extra money if you use a later intake.
If its a good motor leave it alone and just clean it up and paint it.
You can get a 500cfm 2v carb too. You could even get 2x1 intake too(ive got one and the matching heads need rebuild)and leave the heads there. Also have stock 4v intake.

 

The intake manifolds for hemi and poly are the same. You can bore a 301 block 3/16" and use stock 331 pistons. Stock size pistons are the cheapest to buy.

 

I haven't seen anything that validates that it is just an underbored 331. a sonic check would be very wise. Keep in mind this Dead Thread is from '09.

 

Plymouth & DeSoto both used Polys that were Dodge Hemi blocks

 

"I wouldn't try the 392 heads on it. Its a tall block" The 392 heads would bolt on, but, besides cyl wall/valve clearance no one piece manufactured intake would fit. You'd have to use a twin log, or a U-Fab welded specifically for the application. Also the 4 leg W/P wouldn't fit, or if using the Chevy W/P the 392 water crossover/thermostat housing wouldn't fit. Would have to fab one.

 

They made a hemi 331, 354 and 392 plus a poly 331 and 354 and the one year only, 301. I doubt very much they made new block casting cores just for the 301 when they could easily bore the 331 casting smaller. Also, in those days blocks were made to stand a couple of rebuilds during their working life and you could bore them 1/8" with no trouble. 3/16" is not that much more, although a sonic test couldn't hurt.

I will also say the Chrysler engines I have seen from that time have precision, fine grained castings and precision machine work. This is confirmed by several old articles in hot rod magazines, on the subject of rebuilding and hopping up these engines, they say remedial machine work is not necessary, they are made to such tight tolerances. Meaning core shift is seldom a problem.

 

I'm really glad this topic came up again, it would be great if I could figure out a way to use a bunch of stuff collecting dust in my garage.

 

I'm putting a 57' Poly 354 Chrysler in my 30' Chrysler coupe. I also have a 301 poly but its in rough shape. Respectable horse power & torque rating stock.

 

I guess I missed the date on this one.