alright i know i am not an idiot, the casting number on my block is 3914638. this site, mortec, gm, everyone says a 327 out of a 68-69 truck. the machine shop measure the cylinder walls and piston in front of me-....3.85, not even a 4.00 bore? how the heck is this possible or am i on crack and don't know it. need an answer asap, a 327 block (ha,ha maybe) is on ebay tonight.

I think Mortec must have a typo. I don't think GM used the same casting number for different bore sizes. Whatever the case you most certainly do not have a 327 block.

Yep, 307....

http://www.cehighperformance.com/new_page_3.htm

about 1/2 way down the page

ok now that i know i am not on crack... where can i get a good bare block in Houston. Has anyone ever built a 307 with at least 300hp???? i know they spin bearing. That is weird though, 2 books, mortec, and i think even this site had the numbers as 327,,oh well.

with the right combo 300HP can be had with a 307 (its literally a stroked 283, 283 bore 327 stroke)

IF you have a large journal 307 crank (9/16" socket for the rod bolts, 2.100 rod journal, 2.449 main journal sizes) you only need to find ANY 350 block to build a 327 out of. 307 crank, 307 rods, 327 pistons (you MUST balance, 327 pistons will be heavier) and away you go. Your heads will be small valve and of little use for decent power. Vortec heads and flat top pistons will make 300 HP pretty easily with a 327. Better still, build the 350, but each to his own. It will cost you less to build (rebuild) a 350 with the potential to avoid a balance job, and pistons will certainly be less expensive.
Best of luck to you Darknight!

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