S/R or S/R torker heads? they are different.
The S/R torker 64cc head is a good head for your 307.
When using this 2.02x 1.60" valve head on a 307 then boreing the engine by .040" is a good thing as it allows for more valve space.
( DO not bore to 4") +.040" over bore for +.040" flat top 307 pistons is plenty.
Then, you want to mill the 64cc heads to get the chamber smaller for good compression on your 307.
(and deck the block too). Do not assume the "64cc heads" are actualy 64cc.
Measure them. I bet they will CC bigger than 64cc. Getting the real compression ratio correct is essential to getting the high perf 307 SBC build right.
You got some good hard parts to work with. Will really shine with the right tweeks.
This is a very good engine to supercharge (but with a low compression ratio).
The S/R torker head gets even better when hand ported. (makes big power)
How do you plan to use this 307? ( consideration for cam/compression/intake exhaust choice.)
It will make very similar power to a 327.
What is the casting number/part number on your S/R heads?
for a high perf 307 you want to get the chamber volume down to about 58cc. ( flat top +.040" over 307 pistons and 10:1cr)
getting the compression ratio right is critical.
Do not bother boreing this block to 4".. You can build a rocking 313CID small block with a +.040" bore and the stock 307 crank.
One of the keys to building up the 307 is don't dummy it down. It like the same things as a high perf 327 SBC.
And will perform very similar when done right.
Last edited by F-BIRD'88; 04-08-2013 at 03:17 PM.