Is this a hemi block?

[Diesel1276]

I saw this block for sale. It is listed to be a 72 casting made for drag racing. It is listed with cylinder sleeves to a bore of 4.100. It is said to be never used and shelved for 44 years. Appears to have four bolt mains. Why would an unused block be sleeved? Did Mopar do this for racers? My thoughts is it was sleeved from previous boring. Any input? Thanks.

 

[Fran Blacker]

Yes look it over for cracks in main webs, just in case. Looks like block is o-ringed.

 

[33 IMP]

Yes, a hemi block.
Sleeved to a much smaller than stock bore, probably to run as a smaller cubic inch motor to fit a cubic inch limited class.
396 cu in, with a stock 426 crank. 6.5 liter, or under 400" class.
Could have been run with a destroker crank for 358 or366 inches too
Run a hemi heads up against a small block chevy or ford.

 

[Diesel1276]

Yes, a hemi block.
Sleeved to a much smaller than stock bore, probably to run as a smaller cubic inch motor to fit a cubic inch limited class.
396 cu in, with a stock 426 crank. 6.5 liter, or under 400" class.
Could have been run with a destroker crank for 358 or366 inches too
Run a hemi heads up against a small block chevy or ford.

Ok that makes sense. Seller stated that it was shelved when NHRA allowed 500 cu in. I appreciate the knowledge. I was thinking a 392 cu in after sleeving.

 

[Diesel1276]

Yes look it over for cracks in main webs, just in case. Looks like block is o-ringed.

Why O ringed? What purpose? Thanks.

 

[Diesel1276]

Yes, a hemi block.
Sleeved to a much smaller than stock bore, probably to run as a smaller cubic inch motor to fit a cubic inch limited class.
396 cu in, with a stock 426 crank. 6.5 liter, or under 400" class.
Could have been run with a destroker crank for 358 or366 inches too
Run a hemi heads up against a small block chevy or ford.

Im not familiar with sleeving. Is it safe to bore back to 4.250?

 

[MiradaMegaCab]

O-Ringing provides the ultimate seal on head gaskets. Especially before MLS gaskets were introduced.

 

[33 IMP]

Im not familiar with sleeving. Is it safe to bore back to 4.250?

No way of knowing without a sonic check. Also depends on the o.d. of the sleeve.
Frankly, the sleeving has damaged the value of the block. Pistons would be a VERY expensive custom set to run it as is, boring out the sleeves is a gamble, and also expensive.
Also,for reference, the row of head bolt bosses inside of the deck, in the valley, is what confirms it as a hemi block. There are kits available to add four bolt mains to regular rb blocks.
Edit: if, IF the sleeves are very thick wall, and IF it was bored over stock to put the sleeves in, you MAY be able to bore the sleeves out to 4.25 without getting into the original cylinder walls. Again, NO way to know what's there without the sonic check.

 

[1 Wild R/T]

If your seriously interested check the deck height... Not uncommon to cut a bunch off the deck, if they sleeved it to reduce displacement they may have de-stroked it too... When that's done you either get longer rods, a taller piston or short deck height....

 

[33 IMP]

If your seriously interested check the deck height... Not uncommon to cut a bunch off the deck, if they sleeved it to reduce displacement they may have de-stroked it too... When that's done you either get longer rods, a taller piston or short deck height....

Always a good idea with an obviously messed with block!

 

[Fran Blacker]

Why O ringed? What purpose? Thanks.

High horse engines to seal cylinders better. Should've looked closer, didn't expect sleeves. With the price of block all kinds of thing are around.

 

[ChargerST]

I saw this block for sale. It is listed to be a 72 casting made for drag racing. It is listed with cylinder sleeves to a bore of 4.100. It is said to be never used and shelved for 44 years. Appears to have four bolt mains. Why would an unused block be sleeved? Did Mopar do this for racers? My thoughts is it was sleeved from previous boring. Any input? Thanks.

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Is that the block that was listed on facebook for $2500? Be careful looks like a scam! One of the comments below was that the seller ghosted a guy as soon as he said he was local and wanted to see the block in person..

 

[Diesel1276]

Is that the block that was listed on facebook for $2500? Be careful looks like a scam! One of the comments below was that the seller ghosted a guy as soon as he said he was local and wanted to see the block in person..

It is. Im two hours away and was gonna go look at it. I asked if he had additional parts and he said Indy 1RA heads with 2.40/1.94 valves for $1500.00. Whether hes pulling one or not, I wanted to understand the difference in the block. I wasnt sure because it has same casting number as my 426 street wedge block and I thought it was machined for four bolt mains. My father said it sounded too good to be true. He said he thought it was sleeved due to a defect. Either way, I appreciate your input.

 

[33 IMP]

I sure wouldn't send/spend any money on it, without laying hands on it first. If it is a scam, I would be surprised if they tell you where it is.
Disappearing when someone local wants to see it is a very bad sign.
The heads seem too cheap.
The fact that a hemi block has the same casting number as your wedge block is suspicious too. Pictures of two different blocks, maybe???
Be VERY careful.

 

[Dragon Slayer]

That is a hemi casting number and by pictures takes the hemi head. Look at 440 pictures of head area and it is different.

I don't understand the 4.1 sleeve and that is oddity. The destroked hemi had different cranks strokes and took pistons with different CD not different bore.

I would want that pressure tested besides magged then figure out cost to machine and build. Otherwise an expensive anchor unless you want to try to make a small block hemi.

 

[Diesel1276]

That is a hemi casting number and by pictures takes the hemi head. Look at 440 pictures of head area and it is different.

I don't understand the 4.1 sleeve and that is oddity. The destroked hemi had different cranks strokes and took pistons with different CD not different bore.

I would want that pressure tested besides magged then figure out cost to machine and build. Otherwise an expensive anchor unless you want to try to make a small block hemi.

Im not sure. I agree with others that its prolly a scam or bad block. The seller listed it with a 4.100” sleeved bore but is telling me its a water cooled engine with a standard 4.250” bore? I thought the price might be a fairytale.

 

[33 IMP]

That is a hemi casting number and by pictures takes the hemi head. Look at 440 pictures of head area and it is different.

I don't understand the 4.1 sleeve and that is oddity. The destroked hemi had different cranks strokes and took pistons with different CD not different bore.

I would want that pressure tested besides magged then figure out cost to machine and build. Otherwise an expensive anchor unless you want to try to make a small block hemi.

Agreed. Probably why it has BEEN an expensive anchor for 40 years.

 

[33 IMP]

Ok that makes sense. Seller stated that it was shelved when NHRA allowed 500 cu in. I appreciate the knowledge. I was thinking a 392 cu in after sleeving.

So what he is saying is that, in the eighties, this block was intended to run in a Mopar prostock effort. Before the 500 inch limit, prostock was a weight per cu in class. The idea here was to build a small cu in hemi, to run a lighter weight car. It makes sense.
However! That doesn't add 10 cents to the value of the block, and the sleeves ruin it, in my opinion.
IF it's not a scam, and IF you want it, I'd offer the 2500 for the block, AND heads. A $2000 set of pistons would be a negotiating point.


Then I'd put a 4.25 stroker crank in it for 448 inches, virtually the same bore/stroke as a 455 Olds. High dollar custom pistons either way. It would need a lot less dome with the stroker crank, might even make the pistons cheaper.

 

[1 Wild R/T]

So what he is saying is that, in the eighties, this block was intended to run in a Mopar prostock effort. Before the 500 inch limit, prostock was a weight per cu in class. The idea here was to build a small cu in hemi, to run a lighter weight car. It makes sense.
However! That doesn't add 10 cents to the value of the block, and the sleeves ruin it, in my opinion.
IF it's not a scam, and IF you want it, I'd offer the 2500 for the block, AND heads. A $2000 set of pistons would be a negotiating point.


Then I'd put a 4.25 stroker crank in it for 448 inches, virtually the same bore/stroke as a 455 Olds. High dollar custom pistons either way.

Absolutely how I took the reduced bore story... And the 4.25 stroke is overall probably the best way to make use of the block.... In spite of how strange is seems....

 

[Runcharger]

Not worth effing with it IMO. Think how that narrow bore is going to work with valves that open near the edge of 4.25 bore. Just spend a bit more and get a normal block that doesn't require custom parts. The Pro Stockers used destrokers not small pistons, just wouldn't make any sense.