What drivetrain would you put in for 30 mpg?

[MrSony]

How has your metric not exploaded yet? Get a 200r4 in there asap. Or a 4l60E/4l80E if you want a computer controlled trans. Your engine is fine. Get a qjet, most fuel efficient source of fuel delivery short of fuel injection.

 

[STLRegal]

An OD transmission and super tall gears. That's the easy formula. Are 2.41s the tallest that GM ever produced?

I day dream that if I I ever wreck my Silverado that I'd rip the 4.3 out and twin turbo it in my regal.

I'm not even sure if it's doable out of the hybrids from the factory. But a hybrid gbody would definitely be unique.

 

[Wageslave]

How has your metric not exploaded yet? Get a 200r4 in there asap. Or a 4l60E/4l80E if you want a computer controlled trans. Your engine is fine. Get a qjet, most fuel efficient source of fuel delivery short of fuel injection.

I have got an NV 3500 that is ready to go in some time this summer. Believe it or not that little TH200 had held up quite well for what it is. I just run the TV cable a little tighter than stock to keep the line pressures up. The tires typically spin before I can get too much torque to the ground anyways. I would like to get a Holly EFI setup eventually, but the Edelbrock 1406 that I have on now is actually working fairly well.

An OD transmission and super tall gears. That's the easy formula. Are 2.41s the tallest that GM ever produced?

I day dream that if I I ever wreck my Silverado that I'd rip the 4.3 out and twin turbo it in my regal.

I'm not even sure if it's doable out of the hybrids from the factory. But a hybrid gbody would definitely be unique.

I believe you could get 2.29's in the diesels. I would love to see a TT 4.3. With a few mods, that thing could rev to the sky.

 

[oldsmobile joe]

Are 2.41s the tallest that GM ever produced?

my 2.29 gears were common in the 78-79 cars. service manual lists a 2.19 or something like that. never seen one of those.
i once had a 400 sbc in a 79 cutlass, turbo 700 and 2.29 gears. drove to california and back. got 21mpg. but my girlfriend got better, 21.5-22mpg, and she drove faster too. god that pissed me off. lol.

if you want to stick with a v8, i would look at a 4.8l LS motor with an overdrive trans, (manual or auto) and some freeway gears. plenty of power and the latest in head technology.

but if you really want to turn heads, grab a late 80s, early 90s ford 5.0l with od trans, good for 27-29mpg. i worked for ford, heard many first hand testimonials from coworkers, customers and friends of their fuel economy. didn't matter if it was a mustang owner, crown vic, or lincoln town car.

 

[Texas82GP]

The Edelbrock carb may be hurting fuel economy relative to a Q-jet. A double overdrive like a T56 is the best way to dramatically improve highway cruise economy. I think an overdrive will get you where you want to be, not 30 mpg, but much better.

 

[Texas82GP]

Also, our gas tanks aren't that big.

 

[lilbowtie]

I'm with Oldsmobile Joe - 4.8 or even a 5.3 w/ the 4-8 option. My 4wd Silverado w/ 3.73s will pull 20 plus mpg but you have to keep it at 65.

 

[Matthew Goeke]

Honda civic B16, but seriously i dont see why you daily that thing if you are going to want MPGs

 

[TURNA]

I have a 5 speed in the garage, ready to go in, but time and money never seem to meet at the same time.

Game over right there

 

[axisg]

I cant see 30 mpg in a gbody. Its just too boxy and heavy in stop and go. Sure my buddies 3rd gen "spare parts" Fbody pulls down mid to high 20's with an ez-efi, alum headed sbc and tko 6 speed. But he drives like a granny and doesn't like to rev it over 2k he's so miserly. Hell the price of his trans alone ( nevermind the efi, ect... ) would pick you up a rice burner that will pull 30-35 mpg with the A\C on.