340 Direct Connection cylinder heads

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dibbons

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Does anyone have a part number for the Mopar 340 cylinder head from the 1970's that was cast iron but with no heat crossover passage? And another question, how much (if any) compression would be lost putting these heads on a 273 with 10:5 compression factory style pistons? Thank you.
The reason I am researching this is that back in the late 1970's, I tried this already once and my ET's went from high 12's to low 13's and I was really befuddled, not to mention disappointed!
 
I think there would be a fair comp loss but to use these heads on a 273 the bores would need to be notched for the valves to clear.
 
You seem to be referring to w-2's; it would take some work to get them down on a 273, it can be done; big question of cost /benefit. There was/is a version out there that had a 55cc chamber, after notching the bores for valve clearance, you might end up in the 9 to 9.5 range starting with a 10.5 piston.

Big question is WHY???
 
The only reason I'd consider that would be on a boosted powerplant, where bigger ports would be ideal and venturi was not a concern.
 
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