On the early Hemi 392, what max bore should of experiance be done. Shore just a hone and custom pistons is best but now its 2025 and one find what one find. This is a nice block but caps is missing ( for me no problem ) and cylinders is nice but its 060 over. Price is not low but decent. -How to see this case ?
With it being .060 over already, I think I would spring for the cost of a sonic test to determine if there is any core shift, and find out exactly how much meat is left in the block. How much more over bore does it need? Finding the correct bore oversized pistons for that Hemi could be the limiting factor, I think I would start there. Having it sleeved it back to the standard bore could be a great idea. Could get costly (would save the cost of a sonic test), but that could solve a lot of problems.
It look nice in hone now so I think I’ll jus need do a fresh out hone or maybe leave it. Ok if wall is enought it's Ok, but how thick do one need ? If one read on webb it's sometimes noting or max 020 and some it's Ok at +.120. To do a full 8 sleeve plus main caps is not worth it even if I can do it myself. Also one need stop for sleeve that mean more bore before sleeve. Its caps/sleeve plus allot of time. I know back in the days ( mid 80's ) we bored V8's 60 over just as shop did not has TRW 30 over on shell.. -I can get a std block with caps but its more money as seller see the case on missing caps but don't maybe see the 60 over as a big case here so maybe little to high price (?) Shore I can borrow it and test ( I don't know anyone has it here but I’ll check for a shop )
What you intend to do with the 392 after its built will have a lot to do with what you can get away with. The requirements to have a very nice street motor has a lot less restrictions then a fuel drag racing motor would have. With a street driven (with occasional hot rodding, not being pushed to the upper rpm range) can get by with thinner cylinder walls, and a few other imperfections and live a very long time without issues. On a street motor, if over bore pistons are fairly easy to find in the bore size you need, I would expect it to be OK. If the over bore pistons you need are easily available, it means that over bore size has stood the test of time., but if only one source has a "limited supply" of the needed overbore size, I would be pretty suspect, that company may have them on the shelf waiting for someone to try them. The old Hemi motors are not known to have overheating issues, so that helps with longer over sized bore survival. A full on drag racing motor (with a blower) will find any faults very fast, a drag racing motor without a blower may last longer.
In the racing days, .030 over was it. At .060 I wouldn't invest to find out if it would work or not. That is not a thick wall casting like the 426 is. YRMV.
Sonic test the block. Here’s a link that @RodStRace posted a bit back. Deals with Chevy engines, so verify. https://www.chevelles.com/threads/whats-correct-way-to-sonic-check-a-block-for.822985/
I would sonic check it, would hope to find .120 wall on the thrust side, but I have run engines at .100 wall. If your bore just needs a light hone, and .005 rings are available in that bore size, you can go with that. Most likely you will be getting custom pistons made anyway, you can get them made anywhere from .060 to .065. I have run lots of my small block Fords at .063, .064, and sometimes .066 bores.
My ideas is this, I like to has a std 392 in parts but add more comp and modern rings and more cam/headers. I think I can run with std caps and rods and valves and std rockers. No blower. This is not racing and I will use a mid 50’s Olds rearaxle ( but new parts inside ) but a Lasalle transmission, so its a limit go wild.. But I will use a rather radiacal cam profile but not over .500” lift. I think I can get 100 HP more HP from std with headers and decent carbs/ignition, but not as I need but for the ’sound’ and rew up. If I need custom pistons thats is Ok but I think I can stay at 060 ( soon I can tell ) -Well I can get a std bore block to ( as I ’m mention = more bucks ) and then just fresh up hone/ but maybe then custom pistons ( std + cyl bore ) -So what what to go for ?
I have always "heard" that .020" is about the most you want to go over with a 392 before the cylinder walls get too thin and the engine runs hot on the street. I'm sure someone will say they went way over that with good results. Some folks above mentioned using sleeves. Here is the Surfers talking about their experience with putting eight sleeves in a 392 block! (skip ahead to 12:55)
Yes the idea they had was thick walls but it did not turn upp well. So one can wonder what diameter one would use and get back to 4" bore ( std 392 ) They did not mention that. It do feel I better get the std block ( aviable ) with caps and pay more ( righ now I has no price info on both of this blocks ) and fresh up hone and order custom pistons. But my own experiance from American V8's from 50, 60, 70's is most of them take 60 over but here on this block's I can't tell, but I always prefere not bore than if needed, I use if a customers take the ticket on custom pistons. Rings is no problem today from Total Seal. What is a good std 392 block worth in USA and say missing caps how much does that effect price.
I imagine early Hemis are hard to find in Sweden. With that said, new sleeves and a rebuild may not be a bad move. Early Hemi pistons are not cheap. There are complete hemis that pop up for sale here on the classified adds. Also, Hot Heads has an online swap meet where you can find complete engines. Not sure which is more, sleeving a block or shipping from the states for a nice, std bore block
They can be find but shore the 392 are more expensive. Custom pistons are way more expensive than call HH for a 30 over to a 354. Freight from USA now is hard for us, the good days are over as after the v-irus we are out of the picture. Containers over is few, dollars to our money is tuff plus we are one of the most taxed people on Earth. Soscialism. Sweden has also huge economic problems, we fall after the rest ( don’t ask me why. But if one like to do something, its just work harder.
The 331/354 had thicker walls than the 392 and could go .125 with sonic check. Thinking .030 for 392, but .060 is certainly max if not too much already, maybe why its up for sale. Sonic check for sure, maybe check vs modern engine width. One person well known here on the board got a 331 that was bored to 4" +.030. Told him it was a paperweight. Best i recall the walls broke/split when he tried to start it.
I got lucky it's at 030, still the caps missing but I has a another 392 set that 'might' works for a linebore, or Hot Heads sell steel caps. Cool is to has 555 heads.
I measured bore and it was near dead on targed at 4.030”. The hone was Ok and it was protected by a thick oil so just minor rust as it came from Oklahoma to Sweden atleast 20 years ago and been storage on a pallet in a cold garage. I will however rehone as to get my idea of cross hatch and profile, but this will not change diameter much. My idea is to has over 10 in compression but not over 11, std crank and new rods. Ross might has a on shell piston ( 99462 ) for this aplication with 1/16” rings.
Fast check on that Ross pistons ( dome 22.5 cc ) and a 0.04” gasket and zero deck and 100 cc in head is 10.5 ; 1.
Allot of good calculators there but I could not open up. I will check later ! ( thanks ) I don’t know how much ex a Feel-Pro what can be call a 0.04” is compressed but one can check that up. I know they has the compressed CC. This was just ruff check as I just got block and noted Ross had pistons. Customs is x3 price plus leadtime. On compression allot is depending on volyme. Add ex + 15 CC and one loose 1 in comp…
Yes, thats my thoughts to not know ’anything’…but I been in US V8 since mid 80’s and heard all this myth/storys.
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