What Drivetrain Combo Should I Use?

[Lawn-Ranger]

I am in process of rebuilding my 1982 Wagoneer and cannot decide what drivetrain to install. Here are my three options:

* AMC 360 V8 with DIY TBI, a TC727 with a reverse pattern manual valve body and a NVG242 or NP208 transfercase.

* AMC 258 I6 with DIY TBI, a TC999 with a reverse pattern manual valve body and a NVG242 or NP208 transfercase.

* AMC 258 I6 with DIY TBI, a T17# 4-speed and a NVG242 or NP208 transfercase.

With these options in mind, here are my constraints:
1.) My current axle ratios are 2.73, the front axle has lockouts and I do not have time/money to regear this year.
2.) I own all the aforementioned components - the 82 Wag is an I6 and I also own an 87 GW that will be sacrificed. Through much research, I understand what it will take to install any of the various combinations.
3.) The 360 and 727 are in great shape, but the 258 and 999 would need to be rebuilt. The condition of the 4-speed is unknown.
4.) When finished the 82 will be my daily driver - 60 highway miles/per day at 55-60 mph. In their current state, the 360/727 combo with a rebuilt 2bbl Motorcraft gets 10 mpg on corn flavored gas. I do not have reliable numbers for either 258 combination.
5.) When finished, the 82 will need to pull a solid 14-15 mpg not to break my gas budget. If I choose the V8, I cannot finish with a 10 mpg truck.
6.) I plan to install a 2-3 inch lift and run 30 or 31 inch tires.

For what its worth, I have read every fuel economy thread I can find on this website, and this is what I have learned: The DIY TBI will not lead to an appreciable fuel economy increase on either engine. The 360 is capable of 13-14 with the standard 727, but can improve on that with regeared axles and an AW4 or 700R4 transmission. With this in mind, the AW4 could be a second year addition if the fuel economy improvement will justify the potential fuel cost savings. On the other hand, the 258 I6 is a known fuel miser capable of 16-20 mpg, but few people can stand the poor power performance when compared to the 360. What am I missing? If I need 15 mpg, is the 258 my only option? Any input would be much appreciated. Thanks.

[Dirtball]

360/727/208

[del]

I'd go with the 360/727/NP208 setup. With the gears you have, the 360 will still move itself OK. Those gears will suck with a 258 and larger tires. I'm not sold on the 999 or the T17# for a FSJ vehicle if it is to have larger tires or go offroad.
Also to consider- the cost of rebuilding a motor and trans,(258/999 setup) will buy ALOT of gas.
Try the 360 combo with the DIY TB and a good tune-up.
Also, try to find axles with the gears you want in them vs. getting the axles you have regeared.
I know you want mpg's, but only a true overdrive trans will get you that.
Hope this helps ....Del

[bigun]

I opened this with much trepidation figuring it was another "which chevy engine should I use" :banghead::banghead: Your best gas mileage maker is a light right foot

[mattmopar440]

401/727/208 :D

[Lawn-Ranger]

Thank you for the responses. I am sold on the AMC drivetrain so I definitely appreciate the SBC comment. I have been leaning towards the 727 as I also have concerns with the strength of the T-17# 4-speed and the 999 as both are considered medium duty transmissions.

In regards to regearing the axles, I am fortunate that I have two sets of usable axles with 2.73 gears. My plan is to run the good set once the truck is done, then spend my time next winter rebuilding the suspect set with a 3.73 gearset in prepartion for an overdrive transmission install.

In regards to the transfer case, is an NP208 that much stronger than an NVG242? I am not a big fan of the NP229 in my GW, but 4HI FT sure is nice in the winter. I purchased the 242 as I really wanted the 4HI PT-FT option - Though I admit there is risk in that I will also be running lockouts, which could potentially damage the transfer case if someone tries to run unlocked in the 4HI FT position. Thanks again.