Where's the Beef?

I've read several times on this site that 1975-6 engine blocks have more metal in them, are stronger, and they weigh eleven pounds more than the earlier blocks. So, what I'd like to know is where's the extra metal? Cylinder walls, main webbing, lifter valley, in the sides of the block, or a little bit more in all the above?

Thanks in Advance,

Steve Cowell

 

Decks and cylinder walls..

Main webs are pretty much all the same..:ball:

JW

 

On average, how much thicker are the cylinder walls on the late blocks?

Do you think there's enough of a increase in material to bore one to 4.375", on a 10.1:1 compression naturally aspirated engine?

Thanks,

Steve