Quote:

i will be dynoing those two combos saturday on my 580.i will also dyno a indy dualplane.i'll post the results.

I would recommend testing the -3 (4500) intake with a cloverleaf shaped spacer to give more intake volume like the 2" adapter does on the -2 (4150) intake. You have to draw the line somewhere when testing, but this is the priority I would give:

-2 intake with 2" 4500 adapter
-3 intake with 2" cloverleaf spacer(stack two 1" if needed)
-3 intake with 1" cloverleaf spacer
-3 intake with no carb spacer (lowest priority)

But on a 580 CID engine, I would think the -3X intake would be better.

1993 Daytona, 5.50 at 130mph (1/8) 1.19 sixty ft (PG). Link to 572 B1 - Part 1