Free Machine work on any early Hemi Block

Discussion of the 331-354-392 HEMIs.

Moderators: scottm, TrWaters, 392heminut

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Bailiesdad
Posts: 433
Joined: Sat Dec 01, 2001 6:00 pm
Location: Maryland

Free Machine work on any early Hemi Block

Post by Bailiesdad »

To dispell the myths floating around that an early hemi block has .375 thick cylinder walls I believe that offering the flowing, absolutely free, will put it to rest.

I will

thermally clean (oven bake)
Magnaflux
shot blast
bore and hone up to within .200 of the cylinder walls thickness
deck
and align hone

ANY 331-354-392 Chrysler block that is delivered with a sonic test report showing each and every one of the 8 cylinders from top to bottom has .375 thick cylinder walls.

I like to back up my posts with certainty.
johnny5
Posts: 128
Joined: Mon Dec 05, 2005 3:52 pm
Location: St Charles, MO

look before you leap...

Post by johnny5 »

I already posted this twice, but I was referring to the 331, NOT 354 or 392 in reference to the .375" wall. I was quiet specific about it too. But go ahead, knock yourself out. Bore thicknesses should be as follows:

331 ~ .350 - .375
354 ~ .275 - .300
392 ~ .250 - .275

Most standard bore blocks should fall within these ranges. They may vary a little with core shift but not too much. When you post your findings, include a picture of the actual sonic test reading of the minimum wall thickness point and mic the actual bore size.
hemi4711
Posts: 22
Joined: Wed Apr 23, 2003 8:36 am

wall thickness

Post by hemi4711 »

I agree my 392 was bored .070 over and I sonic checked it first. Most checked at .300 to .280 plenty thick for a street use. 407 cubic inches.
johnny5
Posts: 128
Joined: Mon Dec 05, 2005 3:52 pm
Location: St Charles, MO

Post by johnny5 »

I've heard that it's not uncommon for 392's to be bored to .100" over. It's hard to find shops that sonic test blocks around here. I was thinking of buying one myself and posting an ad in all of the local car clubs for sonic testing to try and recover some of the cost.
TrWaters
Posts: 390
Joined: Fri Dec 14, 2001 6:00 pm
Location: Vermont
Contact:

Post by TrWaters »

I dont believe that I read where anyone claimed that all blocks had all 8 cylinder walls .375 thick top to bottom, in full circumference. We all know that would only happen with a billet type block with independent sleeves. So I would suggest that we all move on from here, instead of trying to get the last word in.
Early hemi to late sb Mopar trans adapters. Precision billet parts for early hemis.
Bailiesdad
Posts: 433
Joined: Sat Dec 01, 2001 6:00 pm
Location: Maryland

Post by Bailiesdad »

The blocks bore to bore centers define the maximum amount of material possible in cylinder walls.

IE current 426 style both cast iron amd aluminum hemi block 4.84 bore centers, (non pro stock 4.9 or IHRA 5.0 bore centers)
with 4.25 bores there is .590 amount of room for cylinder wall materials.
With 4.5 bores there is .340 amount of room for cylinder wall materials.

.590 divided by 2 equals .295 MAX wall if siamese bore for 4.25 bore
.340 divided by 2 equals .170 Max wall for 4.5 bore

Most newer billet blocks have .100 to .125 thick sleeves or Cast iron have siamese ( joined cylinder walls) bores

Early hemi block bore center to center = ????? (HINT 4.5 RANGE)
331 bore
3.8125 + .750 cylinder walls equals 4.5625
354
3.9375 + .750 =4.6875
392
4.00 + .750= 4.750

see if the hard math will allow it...REMEMBER room for WATER JACKETS...INBETWEEN THE CYLINDER WALLS INSIDE THE BLOCK..


you can get the EXACT bore centers on just about any block from BHJ, any head gasket manufacturer, or for Hemis, Chrysler tech service manuals.

I will leave it at that......
johnny5
Posts: 128
Joined: Mon Dec 05, 2005 3:52 pm
Location: St Charles, MO

Post by johnny5 »

The bore center calculation does seem to show that this wall thickness in a 331 leaves exactly 0.000" between cylinders. My chunk o' wall came from the thrust side. I believe there is more material there than on the sides between the water jackets. It's also possible that I had a massively core-shifted block. Either way, it would be nice to see some actual numbers on several blocks just for interest's sake. Each block is different. I plan to sonic test mine before massively overboring it because of this but still think a 331 can be easily overbored to 4.00". 354's are basically overbored 331's with minor cosmetic changes made to the outside of the casting.
wayfarer
Posts: 83
Joined: Sun Feb 26, 2006 4:16 pm
Location: Peoples Republic of Oregon

wall thickness issues

Post by wayfarer »

I have a shining example of massive core shift in a 392. the 'piece' is on a shelf in my shop... The 392 was only 0.040 over and the chunk of cylinder wall is only about 0.090 thick. I highly recommend sonic check before doing anything to a 392.
erk_f-100
Posts: 9
Joined: Sat Mar 24, 2007 8:15 am
Location: Norway

Post by erk_f-100 »

I had my 1954 331 standard block sonic tested after I got it here to Norway because I thought to bore it up to 354 (had a real nice set of 354 pistons). My block varied between 0.16 to 0.31 and averaged at around 0.25 wall thickness. Needless to say I only went up 0.03 to clean it out.I still have the complete sonic testing of the block-all 8 cylinders and 4 different places in each.
Bailiesdad
Posts: 433
Joined: Sat Dec 01, 2001 6:00 pm
Location: Maryland

Post by Bailiesdad »

Thanks for the input Erik, nobody has taken me up on my offer so far and the largest and loudest poster has decided to sell his Hemi parts to fund other things. :lol:
erk_f-100
Posts: 9
Joined: Sat Mar 24, 2007 8:15 am
Location: Norway

Post by erk_f-100 »

I just bought a 1956 331 marine block.According to info found here I think that
A) this block should have a 5% nickel content making it tougher than regular auto blocks
B) thicker walls than the auto block ,maybe some kind of 354 block bored to 331
C)Bare block should resemble my 1954 331 auto block and the later truck blocks(xtra water holes in the front etc) so I can use all the auto parts I've assembled for my 1954 331.Confirm please!!
I'll be sonic testing this block too as soon as it gets here to Norway- I'll send the results as soon as I get them.
johnny5
Posts: 128
Joined: Mon Dec 05, 2005 3:52 pm
Location: St Charles, MO

Post by johnny5 »

Bailiesdad wrote:Thanks for the input Erik, nobody has taken me up on my offer so far and the largest and loudest poster has decided to sell his Hemi parts to fund other things. :lol:
If you're referring to me, kids happen :roll:
Last edited by johnny5 on Thu Mar 29, 2007 9:03 am, edited 1 time in total.
Bailiesdad
Posts: 433
Joined: Sat Dec 01, 2001 6:00 pm
Location: Maryland

Post by Bailiesdad »

Johny did you find your mic to get the crank sizes?

My customer also wanted a copy of the sonic check report on the block you were doing last year.

Plus, could you post real clear pictures of the heads' surfaces and chambers.

I need to give him a ball park estimate how much it will cost to get them ready to rebuild and use.

I will post all the information on your parts, if and when we get them done.
johnny5
Posts: 128
Joined: Mon Dec 05, 2005 3:52 pm
Location: St Charles, MO

Post by johnny5 »

Hey Peter,

If you're talking about the 1955 331 block I had a while back, it checked at an even .200" wall thickness all around. Not good for much more than a 60 thou max overbore. This is why I'm an advocate of sonic-checking. It's alot thinner than the one I had with the cracked wall. My Plymouth sold yesterday so I'm keeping all of my hemi parts. Thanks for your interest though. I 'm thinking about documenting the build from start to finish and posting for all to see. I probably won't have time (or money) to work on it for a while though.
Bailiesdad
Posts: 433
Joined: Sat Dec 01, 2001 6:00 pm
Location: Maryland

Post by Bailiesdad »

You may want to edit this ALSO>

I already posted this twice, but I was referring to the 331, NOT 354 or 392 in reference to the .375" wall. I was quiet specific about it too. But go ahead, knock yourself out. Bore, thicknesses should be as follows:

331 ~ .350 - .375
354 ~ .275 - .300
392 ~ .250 - .275
johnny5
Posts: 128
Joined: Mon Dec 05, 2005 3:52 pm
Location: St Charles, MO

bailiesdad needs to be banned!

Post by johnny5 »

This kind of BS is why nobody likes you. Good or bad, facts are facts. All blocks are different. I got a really bad one for a big overbore. 331's are still thicker on average than the rest.

FYI - I hung up on you because you think your stuff is like gold and everyone else's is worth nothing. You said '354 blocks go for a hundred bucks'. Yeah right. No one out there will sell a 354 block for a hundred bucks. As a matter of fact, you yourself left a message on my voicemail a while back when I was still looking for a block saying 'I won't take a picture of it and won't measure the cylinder bores - price is $500, take it or leave it'. Make up your mind you hypocrite :o

Scott, do everyone a favour and ban him from your site. I'm not coming back until you do.
Bailiesdad
Posts: 433
Joined: Sat Dec 01, 2001 6:00 pm
Location: Maryland

Post by Bailiesdad »

You asked me for a 392 block, the one that the bore size was listed. There was no need to measure it again. Sold it for $600 after baking and shot blasting it for the new owner.

I have a couple of bare core 354 blocks, I will sell for $100 bucks each. Never sold a bare one though, most are looking for 392s.

A 354 block that is magged, baked , shot blasted with a fresh bore is 500 bucks or more.. remember, I carefully explained that to you.

You hung up when I asked, for a potential customer, for the sizes on the 392 crank you were selling. Remember YOU called me.

Now that is both sides of the stories.... :D BYE

PS I get lots of calls asking for help and parts, so I must be doing something correct.
392heminut
Posts: 488
Joined: Sat Nov 30, 2002 2:16 pm

Post by 392heminut »

Well, this is another topic that has turned into a pissing contest and is not benefiting anyone so I'm locking it.
Owner of the Poor Man's Hemi Cuda
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