Quote:
Originally Posted by T.J. MCCAULEY
That's not bad considering...a 292 would probably get as bad or a whopping 1 mpg better only cause its a little bigger...less engine stress...dump an ol 5 speed GM trans...oh what was it...Spicer 5 speed? That'd give you another gear. lol Something like .76 OD I think...not sure..it was on that GM heritage site. Not sure what the 292 in my C-10 gets...Wonder if the mileage increased a tad with the 4 barrel, headers, an HEI...they say it should get around 16-18 with those mods...but who knows. lol! Put a turbo on that 250..then when you WOT it from a stop light you be up to speed so fast you will have hardly used up any fuel.  |
Yeah, I'm interested to see how the 292 does in comparison; should have it in there before too long.
The old Clark and Spicer 5 speeds were mostly 1:1 in high gear, and they are giant medium-duty (like a C60) transmissions anyway; AFAIK they all (or most of them, anyway) also used an SAE bellhousing with all the bigger clutch stuff.
I almost bought a NV4500 the other day, but I think I'd like the SM420 with an auxiliary OD box better; the extra in-between gears would be very nice to have sometimes (towing, etc).
The mild turbo thing has crossed my mind many times; still might have to do it at some point.
I'm not really sure on the modded vs. stock mileage thing; that's next on the list. I have a little Weber progressive 2bbl carb and a GM HEI that I'm going to stick on there at some point soon, but I suspect that the gains from changing over from a setup like mine that's in good working order will be less than commonly advertised; it'll be interesting to see how it goes.
