Fuel Economy, Hypermiling, EcoModding News and Forum - EcoModder.com - View Single Post

Galane · 06-26-2014, 02:00 AM

I bought a 1982 GMC Sierra 3500 1-ton dually flatbed with a 350 and TH400. Needed it for hauling heavy things like lathes and milling machines.

Only cost $1,000 with 127K miles. It was a city owned truck and came with a massive folder of maintenance records so I know things like when the transmission was sent off for repairs and the engine had new rings and bearings, every time the oil was changed, when new pieces were welded onto the cab to cure the typical GM pickup rot...

Since it has a 2bbl carb (must have been changed because the VIN indicates a 4bbl) and the trans is only a 3 speed with no lockup I figured at some future time I'd upgrade it to TBI and possibly swap in a 700R4 to help it suck less gasoline.

So I was perusing Craigslist and saw a 1991 Chevy pickup 350 with TBI and 700R4, u-pull for $175 because the owner just wants to make a pickup bed trailer. Yowza!

I can grab all the parts other than the radiator and AC stuff that's already spoken for. (My truck doesn't have AC anyway, darnit!)

I contacted the guy, went and heard it run, sounds great. Flipped over $100 and said I'd be back this Friday morning to get it.

Did a 40 mile round trip today to spend $260 on new 2.75" thick tongue and groove laminated boards for the flatbed deck and used nearly 1/4 tank of gas.

I swear I heard a constant toilet flushing sound from the engine compartment... Using a GPS speedometer I found the truck's speedo reads about 5 MPH fast all the way up to at least 60, so that'll have to be addressed with the upgrade.

Back home, I jacked up one rear wheel to give it a couple of turns and found it has the 4.56 gears. (Anything on the truck that had an axle code is long gone.)

Timeline for the upgrade project has been moved up to ASAP! The overdrive will drop the final ratio to 3.17.

Another benefit of the upgrade will be a boost from a paltry 160 HP to 190 or 200~210 if the 1991 isn't a 1-ton.

Costs so far.
$1,060 Truck (6% tax)
$175 engine, transmission and all wiring etc
$260-ish 18 new 10 foot boards for decking

Call it $1500, minus whatever I can get for a well maintained and good running vintage 350 and TH400, plus whatever things I may need to buy for merging the 1991 drivetrain with a 1982 truck.

DSCN0283 by g_alan_e, on Flickr

PS: The seat has very nice red velour upholstery and is quite comfy.

06-26-2014, 02:00 AM	#1 (permalink)
Galane Master EcoModder Join Date: Jul 2009 Location: idaho Posts: 282 Thanks: 0 Thanked 96 Times in 74 Posts	Heavy duty modding. I bought a 1982 GMC Sierra 3500 1-ton dually flatbed with a 350 and TH400. Needed it for hauling heavy things like lathes and milling machines. Only cost $1,000 with 127K miles. It was a city owned truck and came with a massive folder of maintenance records so I know things like when the transmission was sent off for repairs and the engine had new rings and bearings, every time the oil was changed, when new pieces were welded onto the cab to cure the typical GM pickup rot... Since it has a 2bbl carb (must have been changed because the VIN indicates a 4bbl) and the trans is only a 3 speed with no lockup I figured at some future time I'd upgrade it to TBI and possibly swap in a 700R4 to help it suck less gasoline. So I was perusing Craigslist and saw a 1991 Chevy pickup 350 with TBI and 700R4, u-pull for $175 because the owner just wants to make a pickup bed trailer. Yowza! I can grab all the parts other than the radiator and AC stuff that's already spoken for. (My truck doesn't have AC anyway, darnit!) I contacted the guy, went and heard it run, sounds great. Flipped over $100 and said I'd be back this Friday morning to get it. Did a 40 mile round trip today to spend $260 on new 2.75" thick tongue and groove laminated boards for the flatbed deck and used nearly 1/4 tank of gas. I swear I heard a constant toilet flushing sound from the engine compartment... Using a GPS speedometer I found the truck's speedo reads about 5 MPH fast all the way up to at least 60, so that'll have to be addressed with the upgrade. Back home, I jacked up one rear wheel to give it a couple of turns and found it has the 4.56 gears. (Anything on the truck that had an axle code is long gone.) Timeline for the upgrade project has been moved up to ASAP! The overdrive will drop the final ratio to 3.17. Another benefit of the upgrade will be a boost from a paltry 160 HP to 190 or 200~210 if the 1991 isn't a 1-ton. Costs so far. $1,060 Truck (6% tax) $175 engine, transmission and all wiring etc $260-ish 18 new 10 foot boards for decking Call it $1500, minus whatever I can get for a well maintained and good running vintage 350 and TH400, plus whatever things I may need to buy for merging the 1991 drivetrain with a 1982 truck. DSCN0283 by g_alan_e, on Flickr PS: The seat has very nice red velour upholstery and is quite comfy.