This winter my buddy wants to add some HP.

Currently, 509CI, solid roller cam, B&M 250 blower, GM rect port heads.

I was thinking, upgrade to 8-71 series blower with dual 750CFM holleys, crane 741 cam, 8:1 compression.

Question on the GM parts.
How much power can the dimple rods and GM steel crank support using ARP stud kits?

Some CNC Dart aluminums would be my choice, but will the GM square port heads work well with a little port work?

Is running 7-8psi possible on pump gas without a intercooler on this setup?

His goal is around 750HP, and reliable. All suggestions welcome.

Go with a whipple, less heat & motor will live longer. I think you are pushing 7-8 psi without an intercooler.

Teague makes 800 hp with alum heads, 509 ci, and whipple & intercooler

You will need better heads. I'm sure the GM rect ports are already limiting performance. With 8:1 and aluminum heads, 7-8psi should fine on 93 octane.

The square port GM's will deliver 750 hp with enough boost, but you're pushing it to do so on pump gas.

The crank is fine at those power levels, and the dimple rods are fine as well with aftermarket bolts (SPS or ARP).

The cam choice is not optimal for what you're doing. The 741 is a great general purpose cam, but do yourself a favor and match a grind to the heads you choose. Madera has his off the shelf customs that perform VERY well in this power range.

No need to run a solid roller, unless you just want to.
Yes, you're looking at needing a larger blower, and whatever you can find that fits your budget is fine.

Screw chargers are great, but your targets are well within the capabilities of a roots blower or a centrifugal (at least an M3).

You really aren't asking for any miracle. This is an established formula, so find you a big enough blower, then pick your heads, and ask the right guy to match up a cam for your application. The rest of it, you're already on top of.

MC

That power goal is easy. My 509 made just over 900hp with aluminum heads,custom cam courtesy Tyler Crocket, a B&M 420 at 7lbs and an intercooler. Runs on 91 octane.