new cast block 440 how mutch can they be bored

[73chargers4404]

does anyone know if you can bore a 1978 440 bored 60 over,i have a book called how to rebuild a big block mopar and it saysyou cant go over 20 over.

[71440charger]

i believe you can go as much as 60 over

[Rolling_Thunder]

+.060"

[73chargers4404]

so the book is bull s##T.

[71440charger]

so the book is bull s##T.

haha i picked up that book at books a million and set it right back down haha

[dodge freak]

I do know back in the 80's hot rod, car craft and others always said on most blocks do not go over  .030. Something about the rings not setting as good and the engine will make less power with a bore thats .060 over than a .030 over bore. Back then there was lots of good blocks to pick over and everything was cheap. Heck , I remember when people threw away seatbelts and you could go down to the junk yard and get a set for $15.00 and they would laugh at you. I seen a set go for $200 and it was in just ok shape. Maybe now it is different and they have better pistons, rings and machine work but I still would not go over . 030 .If you do it might run fine but they used to claim the .030 would make more power.

[RD]

the 440 block can only be bored up to as much as the sonic check states it can.  It varies from block to block if you want to be critical.  Go here and find the truth:

http://www.440source.com/blockinfo.htm

[71440charger]

the 440 block can only be bored up to as much as the sonic check states it can. It varies from block to block if you want to be critical. Go here and find the truth:

http://www.440source.com/blockinfo.htm

yep 60 over like i thought

[RD]

the 440 block can only be bored up to as much as the sonic check states it can. It varies from block to block if you want to be critical. Go here and find the truth:

http://www.440source.com/blockinfo.htm

yep 60 over like i thought

you are right in general, but if a block sonic tests out to .070 or .080, then guess what, that is what it can be bored to.

[71440charger]

you are right in general, but if a block sonic tests out to .070 or .080, then guess what, that is what it can be bored to.

if you can find pistons for that

[RD]

CUSTOM BABY!!!  really... not really, you "could" use a 400 piston and machine its dome to fit, that is if it is a dome piston.

400 block = 4.34 standard bore

440 block = 4.32 standard bore

440 block = .070 + 4.32 = 4.39 or .080 + 4.32 = 4.40

400 block = .050 + 4.34 = 4.39 or .060 + 4.34 = 4.40

You may just have to machine the piston somewhat for proper fitment.

[andyf]

The late model blocks tend to have at least one thin cylinder so be careful.  It is fairly difficult to find a late model block with all eight cylinders thick enough for an 0.060 overbore.

[Mike DC]

     
Mopar's marketing people wouldn't let the engineers publicly say that the 1976-78 blocks had softer iron in them.  So the engineers called them "thin-wall blocks" to warn hot-rodders about them.  The cylinder walls aren't actually any thinner than the earlier blocks, though. 


Anything is safe to go .030 or .040 over.  If you wanna go .060 oversize then any 440 block will more than likely be fine, but you should sonic-check it before you spend your money on a bore that far.