The LS1 is an awesome motor, alot of engineering is in that motor, head design (Stolen from a Cleveland Ford),program etc, just don't start modifying it, unless you get a 6.0L truck cast Iron block, as the aluminum blocks suffer from Core Shift and failure once you start putting boost or N20 into them, or just making some good power....As far as MPG Vs. HP, its all in the cam, final drive ratio, and programming, mostly the programming....I think GM spends more time in this area than Ford. You start running DFI and playing with the programs watch out... One of my friends has an 89 Mustang LX 306 NOVI 2000, 15 PSI, full cats, air pump etc, with his emmisions program gets over 25 MPG, and has made a best of 720 RWHP, has gotten over 150 HP just from tuning his PMS system with Wide band O2....Other friend 95 Camaro Z28 Convertible , LT1 stroked to 396, FAST DFI, 12:1 on 93 Pump Gas (Gotta love reverse flow cooling), 3500 Stall w/lockup 3.73 rear, has ABS, A/C, drives like a factory car, his wife drives to work all the time...Race weight 3980 lbs... went from 12.40 with stock computer, and got 20-21 MPG driving to and from the track, to 11.96 and 27-28 MPG driving to and fromt he track, with tuning and FAST DFI, same car, same track, same skinny ET streets on stock rims...This was @ Lebanon Valley which isn't the highest, but you will run 1-2 tenths quicker @ Englishtown than Lebanon......anyways LS1 great motor in stock trim, not a good one to modify heavily, tuff to keep clutches in them, but awesome power and extremely smooth....Fords 4.6, John Coletti said it best a couple of years ago when they built the Super Snake and I even said yeah right at the time "The 4.6 is going to make the OHV V8 (302/351 etc) look like a Flathead when the OHV V8 was introduced in terms of power." By the way how many people do you see driving a "Stock" Mustang Vs. a Stock Corvette, isn't that why we buy Mustangs, Bang for the Buck and Aftermarket......I did.....Gotta play with em'....
Brian
www.teamcracing.com