I acquired a 400SBC block this past weekend. I will be rebuilding this when my 350 decides to give up on me.

I am thinking of adding splayed steel 4-bolt mains to my 400. BUT, since the machine shop would have to align hone the mains ... this moves the crankshaft UP in the block a few thousandths. I can see this causing two problems...

1) extra slack in the timing chain
2) pistons somewhat ABOVE the bore

How can one get AROUND these two obstacles?

Also - there is no guarantee that the main caps currently on my 400 are in their original location If I decide NOT to go with the splayed 4-bolt caps then should I be worried about this? I have heard that the main caps should always be reinstalled in their original locations in the same direction. I am sure that the caps are not currently in their original location since somebody removed the crank from the block. They probably just put the mains back on in any manner that was the quickest

Tim


------------------
TRAXION's 1990 IROC-Z
Best Time = 12.244 @ 112.51mph (1.778 60' / 7.819@88.32mph in the 1/8)
All Natural. No Force. No Drugs. Stock Bottom End. Stock Body Panels.
Gunning for NA 11's after installing Hooker LT Headers and reducing weight.
-=ICON Motorsports=-
Moderator: PROM board at thirdgen.org

 

you might want to just keep it a 2-bolt main because i was considering the same thing with my 400 but my machinist, and the book "John Lingenfelter on modifying the smallblock chevy" said that the 2-bolt blocks are actually stronger because the 4-bolt blocks have less material in the main webs, (you have to consider the larger main journals of the 400 crank)i heard the best thing to do is keep the 2-bolt splayed style caps, and just install studs.
hope i was some help.

------------------
87 IROC-z 305 TPI 5spd Borg warner 9-bolt 3.42 posi 4 wheel disc, no mods yet,just got it.

 

Most 400 blocks can hold close to 600 hp with stock two bolt mains. I know a guy that is using a stock bottom end (565 rods and all) with about a 250 hp NOS shot.

Stud the mains and it will hold most anything. You might want to check the classic section on camaroz28.com.

Like http://web.camaross.com/bb/Forum13/HTML/002968.html

and
http://web.camaross.com/bb/Forum13/HTML/002514.html

In some cases, the main caps have numbers that run in the proper order from front to back. Comp and many others also offer timing chains that have been shorted for just such block work.

[This message has been edited by jcb999 (edited October 30, 2000).]