Matt,
I have been running a 8.000 index, calculated HP is 740 HP, on the dyno it ran 713.
I would like to run 7.500, using Wallace Racing Calculators, I think I will need 913HP.
I can get that by dialing up the blower (currently running 28% under driven with a 95 pill). and reducing the size of the bypass pill (more air and fuel).
The block was carefully picked, no undercutting of the mains, I have a valley brace. The block was a RamAir III which means it has stock four bolt mains.
There is nothing else stock inside, all good stuff.
The block is not hard blocked
I have asked several "Pontiac experts" and gotten several responces
"Glenn,
I don’t see any problem with that. I’ve had a few guys do this type of combo and the blocks seem to fair OK with it. Now don’t be shocked that in time it gives up, but you should get a few years out of it? "
First reply from this person
"The cast main caps will be the weak link. It will last until it fails. The aftermarket steel caps and upgraded dowel pins with main studs will help to hold the block together. The 750 hp is stressing the stock caps. The 900 hp and the rpm will increase the stress greatly in the block. If the caps and block fail usually everything is lost.
We would use a new IAII block from All Pontiac for the combo.
Let me know your thinking."
Second reply from this person
"The caps are cast the area around the long ½ bolts is the thin area. They usually break in the bolt holes on the long bolts. That is the thinnest area on the cap. Maybe ¼” to 5/16” of material on each side of the bolt. The aftermarket caps are thicker and stronger. The weak link usually fails first. The 750 hp is a large amount of stress pushing on the crank. We broke the caps and block in the 700-750 hp and high rpm back in the mid 80’s. I had the steel caps made to be strong enough to hold the block together. We also use upgraded dowel pins in the stock blocks. The IAII block has the steel caps with splayed outer bolts, 3/8” dowels and the main caps are recessed. We use the IAII block for 700 + hp combos now that we have it. We did not have it in the 80’s and early 90’s.
Just info for you to use in your consideration."
"Hi Glenn, Well that's a loaded question lol. I have seen some turbo engines make 1500 plus HP and live for several seasons and I have seen 500 HP normally aspirated engines cracked between the mains and cam tunnel. So I would say it all depends on the tune of the engine. Obviously when the engine isn't HAPPY it's going to let you know. So to sum it up 400 to 2000 HP if tuned properly and nothing acts up."
