OK, since they are old school, I thought I would post this here. If it gets moved, so be it.

I have had a couple of 392 HEMIS and around here, the non adjustable valve motrs bring approx 2K. The 354s a bit less and the 331s a LOT less. Why are the 331s so much less desirable? I know where there is another one and am contemplating picking it up, if for nothing else, the valve covers and mabe for use on another project down the road like a ratrod or something to drive locally?

Dave

The way I have always understood it is partially availability and partially desirability.

The 331's were available for the longest time from 51-57(?). So there is more of them. Then you have the bellhousing issue with the early one's which makes adapting a different trany to them more difficult. The later one's (mid 54- to 55 up) as I understand it are more desirable because they have better heads which can be used with the 392 or 354 blocks.

The 354's are bigger horsepower, fewer made so there is less availability and more desirability.

The 392's are a bigger step up on horsepower, additionally there is the nostalgia with the 392.

Not counting the industerial versions.....

The 392 bigger is always better. THe 392 had a production run of 57-58 and only in the high end Chryslers.

The 354 again bigger than than the 331, only in the high end Chryslers (with the exception of a hand full that ended up in 1957 Dodge D501 cars). Production was 1956 only...again with exception of D 501. THere were industerial/truck versions made that carried over into the follow on years.

The non-extended bellhousing 331 were made 54 1/2 thru 1955 (and again industerial versions were carried on for a few more years). These also had the bigger valve heads and used a dry intake.

Extendned bellhousing 331 51 thru early 54. Besides the bellhousing issue these had the smaller valve heads and used a wet intake.

By todays standards none of these engines individually were high production the very high production rate can be atribued most to their preformance reputation.

a quick sum up would be 331s are hard to find any parts for and did make any real high power most were 2bbl engines. 392 is just a bigger 354 lots of same parts, lots of speed parts around for last 50 years and also the hot rodder motor of choice with all the atoptors made now like chevy water pump,plates for 350/400 or 700r4 chevy trans. make good power and look great with big huffer on top and drop into a 32 ford

Actually parts are readily available for all 3 and it costs virtually the same to build any of the 3. The 331 and 354 are both low deck blocks with virtually every part except the pistons being interchangeable. The 392 is a tall deck motor with a lot of parts that are unique to it including the heads.

Unlike most engine families where there is a tall and low deck version and a wider intake manifold to make up for the difference in width between the heads, the 392 made the heads wider which results in intake manifolds being interchangeable for all three engines and the heads not. Heads from a 331/354 can be used on a 392 with spacers (also readily available) but the only way to run 392 heads on a low deck motor is with something like the Weiand Drag Star 2 piece intakes.

For their displacement the HEMI head motors generally make better HP than only other head design (all other things being equal).

Let’s face it most people who put a HEMI in a Hot Rod are really going for the WOW factor. Equal or even more horsepower can be made a lot cheaper with more modern engines. Any HEMI is visually impressive and in the case of the 331/354/392 only someone VERY knowledgeable would be able to tell the difference between them at a glance.

If you're into the early HEMIs the 392s (or stroker versions) are the ultimate bragging rights, and that's pretty much what you pay for when you buy one.

This is the HEMI I built for my 37 Dodge. Without a looking at the casting numbers or measuring the heads it would be hard to tell whether it’s a 331 354 or 392. It does happen to be a 331 (now out to 341).

Mike, what kind of HP is that one putting out? Also, does anyone have pics of the 331 with the extended and non extended bell housing? I may go look at one for sale and pick it up if its cheap enough and need to determine whats what.

Which one is the one thats more desirable, extended or non extended and why again, because the trans can bolt up to it- is that correct and which trans are best for them?

Dave

Here's one I pulled off E Bay. It looks like and for all intents and purposes is a bellhousing cast as part of the block (the non extended version looks like the back of any block). Basically that bellhouing you see is not removable.

Although there are a few aftermarket adaptors available to that will allow later transmissons be be bolted to the extended ballhousing the selection of transmissions you can use is very limited.

Additionally the extended bellhousing version has the small valve least deseriable heads.

On mine without putting it on a dyno I'll never know for sure....I would guess an 325-350 honest HP at the flywheel.

The hemi's had up to 390 HP from the factory and some came with 2x4's. With what is available today you can easily aprroach any HP you want. My 392 in my 40 ford is all the motor the car can handle.