Taking 1974 360 block .60 over

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Dalton697

Dalton697

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I was wondering anyone's experience has been taking a 1974 360 and boring it .60 and turning the crank to .20 thinking if doing this putting 10:1 pistons in it.
 
Why?? Do you need to do it to clean it up or just to say you did it? It won't make more power and the cylinder walls will be very thin and flexible. Get it checked for cylinder wall thickness and then decide.
 
If it hasnt ever been bored, just do it .30 and the cylinder walls will be much stronger.
 
Took it a part and it was already bored .30 over and .10/.10 on the crank really just trying to clean it up...my understanding is the 60 & 70 block had thicker cylinder walls...really concern heat issues, guess I should say for those reading it has j heads, and matching numbers hp exhaust manifolds and was looking to keep those rather the going with headers and stock radiator which has been flushed
 
How many miles did it have on it? It may not need to be bored at all.
 
Not sure on the miles, speedometer shows 119k, pulled the motor due to soft plug leak between motor and transmission, the 727 needed new torque converter front pump and seals, so figured I would rebuilt the motor at the same time so I know what I have...after I took the motor to the machine shop he found it a little scarred and already .30 over, he comment that there is plenty of room to take it .60 over but some guys don't like to go that far so figure I would ask
 
If it'll clean up at .040................Done.

As far as .020 on the crank, if it needs it it's fine.
 
I agree with the others if it'll clean up at .040 over do it, Block would be stronger and .040 pistons are easy to get being stock 340 bore.Also give you another posible overbore to .060 over down the road.
 
You guys act like .060" is the apocalypse. :axe:

Yes, it would be better to go .040" if you can. And if you're really planning on making a ton of power, then it would be best to have the block sonic checked so that you know what you're dealing with.

But I wouldn't worry too much about .060" over on a mild/moderate street engine. I'd venture that there are a heck of lot more 360's from the 70's that will take a .060" over bore just fine than there are that won't. And if you're planning less than 450 hp, I wouldn't stress out about it. Now if you're planning a big money build, then it might be better to just go find a standard block, core 360's aren't all that expensive. Unless you're talking about a matching numbers gig.

If you're really concerned about it, the only way to ACTUALLY know is to have your block sonic checked.
 
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