max over bore for a crate??

[dirty white boy]

i know ive seen .010 over pistons for a crate but whats the leagle max over bore??

[hipower17]

.05 i think, is this right brad?

[fastford]

my understanding from our local certified builder is .030 , but i dont know if thats all thats allowed or all the block will stand.......

[dirty white boy]

.030 what track promoter said,..for seca i reckon...

[brad hibbard]

HOLD UP Guys

I am assuming we are talking "legal" crate engines (per GM)
There are NO legal oversize pistons available or permitted---NONE---Nada
back in the beginning of crate racing there was a high limit piston and it was .001 over NOT 10
even that piston is no longer available
GM specification permits the bore to be a maximum of 4.008
with the permitted piston .008 over will not live very long
we have found that .005 over on the bore will survive but is still not prefered

in review--4.008 maximum bore size
NO oversize pistons

there our some series (mainly pavement) that permit some overbore but anyone that runs GM legal-- the above applies

hope that helps
Brad

https://www.race-1.com

[fastford]

so in other words , when its wore out , throw it away , the builder that told me .030 , must have been saying the block could be bored .030 , he is in talladega and builds legal crate engines for folks all over the south east , not disputing what you say brad , as i dont build them , but i will ask him tomorrow , also im talking nesmith , or now durance lane......

[hipower17]

brad hibbard is the man to ask when it comes to questions about crate engines.

[brad hibbard]

fastford,
it is amazing how well the blocks actually wear with decent maintenance
I am talking years of service without substantial wear
but yes --when they are wore out their life as a crate engine is over
however it is still a 4 bolt main small block chevrolet and can be sold to other applications easily
a new block is in the $800 range and I have sold many used blocks for $350 that need to go over bore
these blocks are easily safe at .030 overbore for other applications (just not crate)

hipower,
I appreciate the confidence.

Brad

https://www.race-1.com

[fastford]

hey brad , just spoke to our local crate builder and what you say is correct , he just freshened a 5 season old engine that only had .003 wear , he said it was mostly because of good carb management , he also said he had one a while back that was less than 2 seasons old and out of spec because of poor carb mgt , I may be up your way this winter and would like to come by and meet you.........

[brad hibbard]

anytime brother---we even have special parking for Ford guys--LOL

[fastford]

cool , I,m sure its up front , right? lol

[brad hibbard]

actually both of my grandpas were 100% Ford guys and would certainly have a thing or two to say about all the bowtie stuff that is here now---

[fastford]

its the same in my shop , but , them chevys pay the bills....

[Matt49]

If you're looking to sell a worn out crate motor, most people look for street rod guys that could use a decent motor to build off of. But a market that goes overlooked is demo derby guys. That's where one of our old motors is going.