Hey guys I have had this project for a few months originally was going to be a retsto but the back of the frame is kinked and shes rusty. So I started converting it to a field tractor, ive shortended the truck up to alittle behind where the cab was. I'm using a 91 EFI I6 with a 78 C6, a 49 Ford F2 4 speed with granny low and a homemade 5:1 Gear reducer with double #80 roller chain. Im currently looking into rear ends either im gona use a dana 60 or 70 rear with 4.10 and 44" tires or if im lucky enough to find a salvaged ford or chevy 2 speed rear with 5.72 and 7.17 with the truck tires. Front suspension will be the ford 2wd front end. My Main question is what does the EFI 6 need to run?? I am removing all the smog and cruise BS. I intend to use the wiring harness from the cab and the computer and plug it all in, im going to cut the front of the cab off and weld it to a old tractor cab so the steering column and electronics will work ( gauges, radio, lights, etc )
Vacuum lines are my biggest fear what ones do I need and what can I ditch? any info is appreciated will get some pictures this weekend when I start bolting stuff up.

 

I'd like to see some photos of your homemade chain box!

The bare EFI necessities to make a I6 engine run would be: ECT sensor(engine coolant),MAP sensor, TPS and of course the TFI module and fuel pumps. The engine may not run as good but it will run with ECU in limp mode as I have done that before with a few different engines.

The smog air pump and associated pipes, vac lines can be removed and capped. EGR can be removed and capped, O2 sensor should be left in, but with ECU in limp mode, it to can be deleted.

The best thing I would recommend is to replace the EFI intake with a carb intake/carb and Dura Spark2 distributor and module. Its all bolt on and just look for a 82 and older truck to get the intake,carb ,DS2 dizzy and module.

Keep the EFI exhaust manifolds, they are a performance upgrade to the old exhaust log manifold.

I too have a 91 F150 thats going to be a yard beater(for now). Just haven't figured out what engine/tranny is going into it. I'm debating whither to use a Isuzu 2.4L engine/5spd tranny or go with a Ford Escort 1.9L/ATX in there. The Isuzu is a 4x4 setup, so a drive shaft to the rear is all I need(yard beater not going to be 4x4 anyway). The Escort engine is FWD so I'll have to weld up the differential in the trans-axle and figure out a drive shaft for it. Escort is also EFI and the Isuzu is carbed, so got to think about that more.

I'll be using a Dana 70 4.88 rear axle from a P30 chassis motorhome I scrapped.

 

I have been looking at roller chain transfer systems today in mud trucks am they seem to be using double #60 chain and that's on 1000hp BB nitrous fueled mudders this little 6 isn't going to come close to that so I'm thinking of running a shaft off the yoke of the c6 to spin a 10 tooth gear then to the 4 speed with a 50tooth set up which should give me a nice 5:1 reduction. If I'm only revving at 2500rpm it shouldn't go to quick since a standard tcase is like 2.5 and in my Powerstroke 4lo is pretty dang slow. I'm a drafter by trade and my work is pretty easy going about after hours shop work so I figure building some sort of system won't be hard at all. As for the axle I was out working on it today, I'm going to cut the back off right behind the front shackles, it looks like if I run 44's and loose all the suspension and move the spring perches on the axle in to bolt it to the frame then it will sit nice and level with the stock 28" front tires.

 

"Doodlebug" is the common term for these.