I pulled the 496 in my Chevelle to freshen the motor, previously the motor had made 1038hp to the tires with a 101mm Precision Turbo and CSU carb. I have a few options as to how I can put it back together.

The pistons have minor scuffing and the bores are about .004" larger than they should be (4.314") so if I hone it and rering it its going to be even looser.

I could hone it out to 4.320 and use a .070" over piston

or

I could buy a new Merlin block 4.500" bore, use my Eagle 4340 crank and H beam rods which would give me 540 CI

I guess what I am asking is it worth spending the $ on a new block? How much power can a production 4 bolt main Mark IV block safely handle??

 

Anyone?? lol.... Seriously considering going the 540 route...

 

depends on you budget and priorities. Was there any evidence of cap fretting/walk on your current combo? How much faster do you want to go?

If you weren't looking for a bunch more power I would use what you have...obviously it has worked well and been reliable. Conversely, if you were looking for "next level shit"...then the choice is obvious.

I really dont have personal experience pushing a BBC that hard...so I cant contribute there.

 

I saw minor cap walk but nothing major. I would like to go a few tenths faster but nothing crazy. I was thinking this motor would make a little more power without having to push it as hard which would be easier on parts.

 

You could to new or even your old pistons , knurl or ceramic coat to bring you back with in tolerance.
If you have the money though a new block would be best.

 

Is your current block filled(half) if not you may want to step up tot he aftermarket block at this point anyway. You are never gonna drop back to 700 hp ;-)

Plenty of 1000+hp stock blocks but there is a limit and time. m