[b454rat]

Put an OD tranny behind the 454. Also they make more power and torque than mentioned, little more horse but torque is close to 400.

Buddy had a Tahoe that was a 5.3, and I was not impressed. At all. I think my old 92 blazer with a 200k 350 had more power than that thing did....

Me, I'd stay with the 454. Build it up some, good heads, little more compression, little lumpy cam, carb/headers/intake/duals, etc. Put some 3.73 in it with an OD tranny, it will get better mileage and still be able to boil the tires off. These motors have been around since 1970 (454s, not big blocks) and still going. LS have been out for little over 10 years? Yes they are a good motor, but can't beat the power, sound and looks of a big block.