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I have a 427 block assembly that was purchased from a Chevrolet dealer several years ago. The block assembly has never been used. The casting numbers on the block are 3915321 with a built date of H-19-7. Does anyone know if this block assy was to be used with closed chamber heads? Any help on this question would be appreciated.
look at casting # again. isn't it 3916321 instead of 3915321? if its 3916321 its appropriate for an early 68 markIV( 390 thru 435 hp including the "430" hp l-88. mike
I believe that you'll find that the casting number is 3916321. A "5" and a "6" are easily confused with casting numbers.
Anyway, if this block was purchased NEW from a Chevrolet dealer then it had to be a lot longer ago than "several" years ago, by any definition of the word "several". Or, the Chevrolet dealer had it in stock for a LONG time before he sold it. In this case the "H 19 7" represents August 19, 1967 (the single digit year on the casting date is unusual for Tonawanda-cast blocks, but it did occur). This block went out of production in 1968. It was used for early 1968 Chevrolet 427 applications, including Corvette. Although it was originally only used with closed chamber heads (open chamber didn't exist until 1969) it can be used with open chamber heads. There is no difference in block configuration required for open or closed chamber heads.
any BBC short block can be run with open chamber heads but not all BBC short blocks can be used with closed chambered heads. most chevy pistons have a number stamped in the top and you can tell if they are open or closed chambered pistons. if there are no numbers on the top of the piston there should be a forging number under the crown. the open chamber engines did not show up till some time in 1969
I know it's premature for you at the moment but when looking something else up I noticed a good article in a '95 Restorer the other day called 'Power Tuning the 427 Chevy Motor' by Ken Anderson. Good tips on making one of these motors behave nicely. When you get to that point - might be worth looking up.
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