428 Pontiac

I picked up a 428 and was wondering what is the most you can safely bore it.

 

Great engine. 0.30 - 0.60 no problem. Manufactured from '67-69, what year is yours?

 

That be a great motor with a set of SD heads on it...
Or RAM-AIR III - IV heads even!!....

 

1969

 

NHRA Super Stock racers routinely bore them .070 over

 

If it is a standard bore, I would stay with 30 over if it cleans it up. Saving metal for a future bore if needed.... Without getting technical and have it sonic tested for wall thickness, 60 over safely.

 

had one a few years back. We went 60 over, and ran a 455 crankshaft, isky cam, and 6x heads. Tons of torque.

 

Why ? SD heads are a different intake-head bolt pattern , and 428 heads flow as good as any Ram Air III . Ram Air IV heads, well thats a different story but who has them laying around on their garage shelves ? You ?