What bore and stroke do prefer?
Go for a large bore, around 4.125 or so with a mid stroke, 3.875-4" if you want to get the best performance. I would never put more than a 4" stroke on anything, kills tq and wont hold up past 7000rpm. Build that setup right and you will be very impressed with your numbers. I know someone with those specs, CP Pistons, crower rods, crower crank and he will turn 8000rpm all day long.500+ hp easy.
I run a 4.03 bore with a 3.622 stroke, basically a 6.0L iron block punched 30 thousandths. I've been happy with the motor. To give you an idea a 4.125bore with a 4in stroke would be a 427. I would shoot for a 408. They make gobs of torque and are perfect for spooling turbos. If your going an inexpensive route from scratch I would consider getting a used iron block from somewhere and punching it 30 over. Most of those blocks are good to 60. The factory 6L cranks are damn strong too. Get some forged internals and go to town... You'll end up with an inexpensive strong shortblock geared towards forced induction.
