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Old 01-14-2021, 06:54 PM   #28
MikeB
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Location: Justin, TX
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Re: 1972 307 cam selection... HELP!

Quote:
Originally Posted by 68Stepbed View Post
Also note that the 307 block can be safely bored +.125 over. That's a 327!
Are you sure about that? It assumes 327 or 350 blocks were used for the 307. Or that 307 blocks had thicker cylinder walls than all other blocks.

At Mortec.com I found 8 casting numbers for 307 blocks. But not a single one of them is used for 327 or 350.

I guess a 307 block with zero core shift could take a +.125 bore, but who knows how much flex there might be in the cylinder walls?

I'd do a max overbore of .060" on a 307, just like I did with the 283 back in the day to get 292 cubes. That was back when the 301 was popular, but a machinist convinced me to stick with +.060". I doubt the power difference between 292 and 301 was even measurable. And heck, a 292 would probably last longer than a 301 with thin cylinder walls.
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Mike
1969 C10 LWB -- bought in 1989
1982 C10 SWB -- owned 2013-2020
Retired as a factory automation products salesman.
Worked part-time over the years for an engine builder and a classic car repair shop.
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