Ok guys I have a 1978 351Windsor I just bought.... Well when I pulled the pistons out I found that it was bored .30 over... the block has a little rust in the cylinder walls so its def gonna have to be bored again... If i take the bore on out to .60 over is this gonna be bad? Is the block gonna be likely to split in half cause I plan on pushing around 600hp somewhere between 575-625hp... Is it gonna have overheating or compression probs... Is it gonna lack low end torque... Any info would be much appreciated.. Thanx guys

 

What does the bore currently measure out to?

 

I have no idea but when I pulled the pistons out they were stamped 30 and someone told me that means its bored .30 over

 

You could probably go .040" and be fine. The correct way would be to have the block sonic checked to ensure there is enough cylinder wall thickness left before boring.

But here is what I would do, you don't have a desirable block, those are the 69 through 74, so put it in the back of the garage for a rainy day orswapping material later and get another unmolested block. The frugal shoper can find one for cheap.

 

I looked around forever and couldnt find a 74 or earlier.... Shouldnt this block be enough to hold the HP I wanna run on it??

 

Atthat power range you will be pushing it with any stock block. I would go after market first, 69-74 second, mexican (yes they made them/and are very hard to find) third, post 74 block last.

What rpm range do you anticipate? RPM is the biggest stock block killer. The other issue on stock 9.5" blocks is cap walk.