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Apr 26th, 2026 | | AD Chevy Trucks  Over 6,000 pictures Brad Allen has an awesome collection of Chevrolet factory pictures that he has set up from film strips. Check them out!
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#76524 04/22/2007 12:36 AM | Joined: Oct 2003 Posts: 5,152 Cruising in the Passing Lane | | Cruising in the Passing Lane Joined: Oct 2003 Posts: 5,152 | I have an '89 1-ton four-wheel-drive with a TBI 454 and a Turbo 400. I don't drive it much because the fuel economy is awful. Best I've ever done with a trailer behind it is 10. And that was rounding up.
The 700R4 or 4L60 are not heavy duty transmissions. I would not want to bet on them holding up with that trailer behind you. The 4L80 is tougher but expensive. Its the OD transmission based on the Turbo 400.
I keep thinking about a swap like this and since I don't use it much I would not save more than a few hundred a year if I could improve milleage by 50%. The economics don't add up. Since I have a more economical car I like to drive I just drive the truck less when gas goes up.
1955 1st GMC Suburban | 1954 GMC 250 trailer puller project | 1954 GMC 250 Hydra-Matic | 1954 Chevy 3100 . 1947 Chevy COE | and more...
It's true. I really don't do anything but browse the Internet looking for trouble... | | |
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