The information I have is from, Richard holdener, speed secrets, definitely worth your time to YouTube the Channel. I agree with the fella said STOP put in an LS. ever hurd of 4bolt mains ? LS is 6 bolt on every Journal. He recently took a high mileage junkyard 6.0 30,000 ring Gap, twin turbo, over 1,400 hp and it survived, not a forged crank not forged rods not forged pistons. When pushed till they pop it's the rod that give out on LS assuming you have ARP bolts. As far as compression is concerned, low compression doesn't help it survive, it does gives you less power, what lower compression is good for, lower octane fuel without Dead Nation. The things I'm saying or dyno proven, I could go on for days trying to help you decide what when where and why, you would have to decide whether or not I'm being biased, talkin out my rear, you should really check out Richard holdener YouTube, be forewarned it's very addictive and extremely exciting when you see just how advanced the LS motor is, it makes all previous (small block) seem like boat anchors.also a 4l60e that can handle the power you're looking Not cheap. There's a lot of debate over the 60 and the 80 because of weight and gear ratio, if it were me I would stay away from your local shop and Monster and go with Gear star.