Tomi72

Hi

A friend has 350 project engine that he's ready to give me for free! It had low oil pressure (and power) and got replaced by a new crate engine. It's currently 040 over and needs to be re-bored. It's a 3970014 casting from -74.

I've heard that one should avoid going 060 over on performance engine. Is this true or just old myth? It would most likely be <400 hp and <6500 rpm engine. All comments appreciated.

rgds Tomi

MIKER

My engine is .060 over but I haven't had it on the road long enough to determine if there will be any reliability problems based on the .060 bore.
I've always heard that you could have cooling problems and block distortion etc...
I've only got ~170 miles on my engine at this time. Hopefully it will be a VERY long time before I can comment on any reliablity problems. If all of the horror stories hold true, my engine is ripe for failure due to the .060 bore, cheap SCAT stroker crank and relatively short 5.656 rods! :smash:

I'll be watching for people with more experience to reply.

73Ken73

My block is bored .060 and I have about 400 hp. The machinest said that my block was an 010 block and was as strong as a non bored newer block. I think the 010 has something to do with the nickel content of the block.

Ganey

Best to go .030 or .40 over. Many hot cars have been built .060 over. Look under the timing cover for the nos. there.

MIKER

Don't worry about the 400 rods.

:cheers:

gkull

The 3970010 were the better blocks. A reputable machine shop can sonic test and tell you if your block is thin in spots. I have had a couple .060 over and some all out sleeved blocks. I never had a problem, but I also never used one with any stroke over 3.5 inches.

There are some 388's on this forum.

tsw71

I'm running a .060" over block in my streetrod. It is a 010 casting and puts out around 500hp. I do have cooling problems, but that is caused mostly by the fact that I am limited as to the size of radiator that will fit between the frame rails. I'm sure the 500hp isn't helping much either though. With the vette having a much larger Radiator, I would not hesitate to run a .060" over block in my vette.

robzr

It depends on the block entirely. Some blocks with .060 will have more meat in the walls than other blocks with .030 bores. David Vizard commented on this with 400 blocks specifically, that some can be bored beyone .060 safely, while some are paper thin (literally) and unusable with a .030" bore. The higher you bore the more likely you are in the danger zone, but have a reputable shop check it out for ya.

I got a 388 (.060" 383) that was built by Fast Times Motorworks. They knew I was going to be making 450+ hp, and they felt there was no problem.

Rob

Tomi72

All, thanks for your comments. It seems that engine might be an ok starting point, especially for the price...

I guess I'll have the block sonic tested to see if it's usable (I'll do a visual check first). After all, I'll loose the cost of testing at most. Much better than grenading the whole engine later.

rgds Tomi