Originally Posted by csx8506
I'm needing some advice. I have a 400 sbc engine that has been bored 060 over to 4.185" with a 3.48" forged sbc crank. I ran it in bracket S-10 without problems. While getting it ready to put in a altered chassis, dropped pan and discovered small pieces of someone else's dipstick. So I tore engine down and now don't know whether to rebuild it or not. I want to put 12.5 or 13.0 cr pistons in it, and make about 625hp, but I am worried about thinness of cylinder walls. I should also mention that it's a 2 bolt block without block filler. Thanking everyone in advance for their advice.
We don't see many 400 blocks safe at 4.155 bore when we sonic test them. Best thing to do is have it sonic tested, Other problem at 625 horse you are rolling the dice.
Filling the block does nothing to make the webbing of the block stronger and with the bigger housing bore and cylinder bores it weaker then a 350 block also 400 decks are weak as well.
400 blocks have a wider bolt patterm on the main caps making the caps weaker then a 350 block.