[Jim_PA]

383, and I'll be the first to use the lame phrase... "there's no replacement for displacement..."

Make educated decisions about the build with someone. Do research on your engine builder. There's no reason you can't get 100K+ out of a rebuilt Gen1 with someone doing quality work for you.

Learn to tune all areas. pick a good carb like a Qjet and enjoy the poor man's fuel injection without the need for expensive custom computer programming.

Gen 1's have been around for so long; it's entirely too easy to make mistakes in planning the build. Big cams with smogger heads and a Holley on top will give you some pretty terrible gas mileage, but at the same time, it's easy to buy mis-matched parts because there are so many options to choose from.

Compare apples to apples. A 5.3 with a factory overdrive trans would certainly be good on gas, but a well-tuned Gen1 with a good overdrive trans (5 speed manual would be my choice...) would be a close match if everything else is built and tuned properly.

I've verified 13.5 MPG on a 2 hour cruise in varied terrain at 70-75 mph at 3-3500 RPM's with my 1:1 4-speed. If I had an overdrive, or slowed down to 60 - 65, I'm fairly confident I would have been in the 17-18MPG range. I run it all over the place, and while in country or low speed driving, I'm always amazed how long it takes for the needle to start sinking if I can avoid driving with the 4-barrel wide open.

No problems in cold weather here either. Hit the key and go.