View Full Version : 400 sbc max bore size?
rabiddawg
10-29-2007, 09:30 AM
whats the maximum bore size for a sbc 400?
bbchevy
10-29-2007, 10:22 AM
GM Block
Most are Junk @ 4.125!
But,if i were to use a Stock Block,i would have it Sonic Checked!Good $$$ Spent,that way you know where the Bores are?
Later
G 8)
jmarksdragster
10-29-2007, 10:50 AM
Try to keep the blocks to .030. You may be able to go more, have the block sonic tested over .030.
davis419b
10-29-2007, 04:53 PM
bbchevy Stanard bore is 4.125
bbchevy Stanard bore is 4.125
I thought standard Chevy BBC bore was 4.250 maybe not!!!!!!!
davis419b
10-29-2007, 05:02 PM
hink , the topic was for a sbc 400 ! bbchevy was the one who posted that 4.125 was max bore for a 400 sbc.
bbchevy
10-29-2007, 05:49 PM
I was NOT saying that the 400 SBC had a Max bore of 4.125!
What i said was MOST of them @ 4.125 are ().
Maybe this will Help?Maybe,NOT?
Later
G 8)
davis419b
10-29-2007, 06:18 PM
WHATEVER !
rabiddawg
10-29-2007, 07:44 PM
hmm im confused now lol
I got a buddy that is attempting to bore out his 400 sbc .060 over.
is that acceptable?
hmm im confused now lol
I got a buddy that is attempting to bore out his 400 sbc .060 over.
is that acceptable?
Only a sonic test will tell you if can be bored out .060 over
Tod74
10-30-2007, 05:35 AM
We have one that is .040 over with no problems but it is very mild.
Gdaddy
11-03-2007, 05:44 PM
you can go .060 on a 400..helps if you run a longer rod to get some of the pressure off the cylinder walls..its best not to go over .040..but my engine is 400 is .060 over with a 4 inch stroke and a 6 inch rod in a stock block with splayed caps..been running it 7 years without failure..
davebat
11-05-2007, 02:53 PM
.060 over isn't too bad for a 400. As long as you have it torn down, sonic test (bout 60 bucks) would be best, also consider filling it to the bottom of water pump jackets and make sure the steam holes are open on the heads.
I have 2, one at .030 over and one at .040 over. Had the one .030 sonic tested and the report showed I could go comfortably to .060.
Gdaddy
11-05-2007, 07:20 PM
alot of guys do fill the blocks..personally i dont..i feel like if the metal is going to expand as it heats the grout will prevent this and cause a cylinder to split..just my opinion..ive had very good luck with my block prep in the past...not to say anyone is wrong..thats just the way i run my stuff..a man should do what he feels is his best course of action