question

[yooper]

what do you all think a truck similiar to this

http://cgi.ebay.com/ebaymotors/ws/eB...408126833&rd=1

with a fuel injected motor and an automatic with overdrive would get for gas milage.

The reason I ask is i'm getting sick of seeing my 98 GMC full size extended cab loose value every day. I figure I could build something like the one above but put a late model motor and tranny in it and have a truck that is just as reliable and just as efficient as my truck.

The good thing would be is it would hold its value. The reason I bought my 98 was it was reliable and efficient. I cant determine any reason why an old one couldnt be built the same way

Plus I think 71, 72 SWB 4X4's are sweet as hell.

thanks for the input

[Blue68]

I love fuel economy questions. Sooo many variables and opinions. In order to get a fairly accurate, or at least best case, estimate, I turn to the current chevy trucks for examples. They have some of the most up to date technology for FI at a reasonable price. Lo and behold, a 6 bangin' Z71 (4x4) gets all of 14/18 mpg. Both V8 versions get about the same. I would suspect you could expect similar results. NOW there are always the variables of your foot, your tire size and axle ratios to take into account as well. The new 4x4 with a v8 have 3.73 or 4.10.

Your mileage may vary.

[1970 CST Short Wide]

Thats a NICE lookin Truck. Buy that one and Drive it

[cdowns]

i would think with the big tires and all something like that with a modern engine and tranny would get about 10-12mpg

[Hutch]

I would like to see the vin.
Looks like the paint on the cowl under the hood it was originally medium blue.
From the size of the master cylinder it may have drums all the way around.
I think that for $8500 you would not want a conversion.
Regardless of the price
That is a great looking truck.

Probably 10 to 12 mpg

Have fun

[yooper]

My 98 has a small suspension lift and 285/75/16's. The truck (with me in it) weighs about 5500 lbs. I get 17-18 on the highway.

I figure the old ones couldnt be any heavier. So with similiar tires and axle ratios with a fuel injected motor out of a late model automobile, in theory they would be similiar mileage.

Aerodynamics shouldnt be much different. the front of my truck is kinda shaped like the side of a barn anyways.

[bpmcgee]

Originally posted by yooper

The reason I ask is i'm getting sick of seeing my 98 GMC full size extended cab loose value every day. I figure I could build something like the one above but put a late model motor and tranny in it and have a truck that is just as reliable and just as efficient as my truck.

Yooper,
That's EXACTLY my thinking! I'm going to be replacing my 98 ricerburner with a 71 blazer. But what Blue68 says is right -- practically impossible to guess. I know I was able to get 15 mph on the highway with a 1974 1/2 ton 2wd. How does this translate to another truck? No idea.
I think, though, just the fact that there are less parts implies that it will be more reliable. So even if the mpg is less, that can be partially offset.

Have fun!

Brian

[Stroker]

I agree a RamJet 350 crate motor and an overdrive tranny should be nearly as efficient as the new trucks, maybe a bit better. Go for it.....Stroker

[Dreaminator]

We have been playing with this a bit too. We figure a 4400 pound truck with a 3.77 posi running 30 inch tires with a Gear Vendor OD (OD = about 2.7) running BB with about 400hp should post about 16-17 mpg. Without the OD it runs ab 12-13 at steady 2300rpms. The GVOD will bolt to TH400 with shift kits and 2000rpm torque converter. We further believe we will have to drive about 65K to break even @$1.75 a gallon. That assumes $2700.00 for GVOD and modified drive shaft. To cover a stock 700 GMOD we're estimating about 23K to break even. If I have learned anything about this build out it is to have a concept and plan in place BEFORE you grind. Good luck.