I know this is nearly immediately said to be a no-go, or suggested to take a different route. However I'd like to share something. This isn't routine practice that's for sure, and it's obscure, but it was done. However it was done in the early '60s and then probably put to practice little, if at all, afterward.

Paxton Products did performance work making hopped-up Studebaker engines, namely the R2 and the more rare R3. The factory R3 cars used Studebaker's 3 5/8" stroke crank and a 3 21/32" bore, because that's as large as could comfortably be bored in the block. The heads made for the R3 however (and it's here I'll connect to the LS) were designed for new Studebaker blocks in development (3 7/8" & 4" bores) but neither came to fruition. Since the heads got paired with the smaller bore block something needed to be done. My uncle describes the R3 work somewhat like this, "It's as if someone at Paxton took a half-round file and ground away material where the valves would contact the block otherwise."



I understand one must be mindful of the piston rings' location relative to the "scalloped" areas. It would also lower LS2's compression ratio, so taking this avenue would work better in a boosted setup.

I don't have an LS2 block handy, would this be a viable solution to mounting 4 1/8" bore heads on a 4" bore block? Would other supporting structures (water jackets or oil passages) not align properly? Or be too close? I'm electing to use an LS2 (or at least the same 4" x 3.62_" dimensions) for my current project to, in some small way, tribute the 364 CID which Studebaker never got to release.

I could select other heads, absolutely. This is one of those things if conditions shook out just right and if a machinist were to say, "Eff yeah! It would work perfectly, given we do X, Y, & Z!" I would go the above route, for the tribute aspect.

 

For the insane amount of money and engineering this would cost to "maybe" work... you could buy the most bad *** set of LS2 compatible aftermarket heads in existence. That being said I don't see you being able to make this work because LS motors use MLS head gaskets and use a lot tighter tolerances than old 60s stuff. Now let's say you make all the rest of it work; you're still throwing a pretty crappy stock head with messed up geometry form the factory onto your LS2... there's a reason guys replace heads on their LS7s right away... If you're a machinist, your bored, and you have the **** laying around and the ability to not care when it doesn't work, hats off to you for trying but you're pretty much going to be wasting your time otherwise. Save yourself some headache and trouble and go buy a set of aftermarket heads before you ruin your block.

 

No reason it couldn't be done...
Custom head gasket might be a problem. And with the valves so close to the block, how badly would they be shrouded by the cylinder wall?
Might flow alot less than expected!

 

Thank you for your responses with input of what would & wouldn't be viable.