[Goatracer1]

A swap to a late model drive train for a daily driver is probably a reasonable idea. For a hobby car swapping the drive train for the sake of mileage alone is not worth the expense or trouble. I added just AOD to my supercharged GTO and went from 6mpg to 15mpg on the highway. I would never recuperate the cost if I went the full route and installed a late model engine.

[besserspat]

Originally Posted by Goatracer1

A swap to a late model drive train for a daily driver is probably a reasonable idea. For a hobby car swapping the drive train for the sake of mileage alone is not worth the expense or trouble. I added just AOD to my supercharged GTO and went from 6mpg to 15mpg on the highway. I would never recuperate the cost if I went the full route and installed a late model engine.

Thats my opinion as well, i have a GN BRF 2004R sitting on a shelf, ill probably use it, put 3.31 rear gears in the 12 bolt, 28" tires.

Then refresh the 7.9CR 781 headed, 454 with a fuel miser HFT cam around 215-220 @ 050 and .530 ...Small diameter full lenght headers and top it off with a fine tuned Qjet and aggressive HEI timing advance and run it on paint brush cleaner 87 octane.

Its funny I get as excited to build a fuel miser engine as I am for a high performance build lol!

Peter

[Formulajones]

Originally Posted by besserspat

Thats my opinion as well, i have a GN BRF 2004R sitting on a shelf, ill probably use it, put 3.31 rear gears in the 12 bolt, 28" tires.

Then refresh the 7.9CR 781 headed, 454 with a fuel miser HFT cam around 215-220 @ 050 and .530 ...Small diameter full lenght headers and top it off with a fine tuned Qjet and aggressive HEI timing advance and run it on paint brush cleaner 87 octane.

Its funny I get as excited to build a fuel miser engine as I am for a high performance build lol!

Peter

I think that engine combo you're thinking of will more than satisfy you on MPG. That's a nice mild 454 with plenty of torque.

Just to give you an idea, I had a 79 1 ton pickup with it's original 454. I pocket ported the heads, put a very mild 220 @ .050 Melling flat tappet cam in it, stock intake with some modifications, and the original Q jet. It was still very low compression (original pistons and heads) 400 turbo and 3.73 gears. That thing would get 14 mpg consistently, and weighed 5600 lbs. I'd just put it on 2800 rpm and cruise. Drove it across country a few times like that. It also towed wonderfully. An overdrive would have easily pushed it to upper teens for MPG, and that was the next step before I sold it.

I've never actually tried to build a fuel miser though, like you I'm more high performance minded, but have managed to get respectable mileage out of some of that stuff anyway.

[Scarebird]

My Lemans was getting barely 10 MPG. My 2016 Sierra gets 22 on the highway, 17 in town. The cost of this changeover is about $5,000 - including the offsetting sale of the 440 Pontiac and M22Z transmision.

So if the Lemans averages 20 MPG with the L84 5.3, the difference is 10 MPG.
A liter of fuel in Barcelona is around €1.70 currently, 3.8 liters per gallon make that $6.46. $5,000 will buy 773 gallons, times 20, would be about 15,000 miles to recoup my cost of changeover - about 2 summers of driving over there.

That said, I did have at one time a 462/2801/200-4R/3.55 combination that would pull down 17 on the highway and mid 14's at the track. It would have been much less work to have stuck with that. But I am never happy unless trying something...

besserspat: I first had 3.23's with the BRF 200-4R, much happier with 3.55's as the 3.23's would lug at 60 in OD.