the aluminum caps solve a couple of problems. 1 they add strength to the caps as the aluminum is stronger than the cast iron factory caps. 2. the caps help decrease cap walk, for further stregnth add the girdle to hold the caps down even more. our caps are made taller so the girdle has direct contact with them. the main problem on the big block is the main webbing breaks when theres alot of power.
So the aluminum helps absorb some shock and keeps it out of the webbing? A billet cap could accomplish the “stronger, less cap walk” goal? I don’t even know if billet steel caps exist.
Yes they somewhat absorb the shock but they can still walk if you throw enough power at them. Adding the girdle helps with the walk as helps limit the flexing, they are basically a bandaid. I thought that the crossbolted cap was the answer, and liked that Indy crossbolted all 5 caps was a great idea till I saw the carnage that Steve Morris showed recently on his youtube channel of his SMX engine having all 8 rods shatter at almost 8000 rpm and the crank still able to rotate, his block design has splayed cap bolts into the main webbing. I can't say if a crossbolted block would have had the same results?
Mopar at one time had a ductile iron cap available as a replacement for the cast iron caps. I scooped up a couple sets before they went NS1 , one set I used , the other set are hiding somewhere .
