I bet this has been covered a million times but:
I want to swap my I6 and 5 speed for a 302 or 351 and a decent manual. I believe my truck is geared 3.73 and features an 8.8 diff. FYI truck is turning 3000 RPM @ 68 mph in 5th gear with stock size tires. Prime consideration here is economy due to gas prices and torque for towing. This is just a work truck. I'll accept 10 mpg or better if possible as that is what I am getting with the I6 now. I need to know:

1. What is a good, strong tranny, manual, that will bolt up to a small block Ford? Also is it hydr. shift linkage or mechanical shift linkage? Smooth shifting is a big plus. I don't want the hassle of installing an auto.

2. What engines feature a bellhousing bolt pattern that matches with the I6? I know the 302 and 351 will, but what 351? M, C, or W? As I will probably do the engine first, and ride the tranny until it dies, then replace it.

3. What parts do I need for a basic carb application swap? I assume: larger radiator, WP, all pulleys, belts, upper/lower rad hoses, all accessory brackets, throttle cable, misc. hoses and wiring, distributor/coil and wires, engine mounts. What about emissions accessories? How about a tach adapter? What about fuel delivery?

4. If I go EFI, what else do I need? I assume a V8 ECU, wire harness (can I modify the I6 with little trouble?), and all sensors.

Thanks in advance guys...

 

it has been covered lots of times, but each person has different reasons. check out this and the inline six and the 260/289/302/ section for several inquiries and the replies and discussions that follow. lots of insight there
now, as to what you are looking for! it sounds as if you want increased mileage as the primary goal. the easiest way to get this is to change axle ratios. if you go to v-8 and do not change ratios, you will not increase your mileage.
i have a 3 speed with overdrive fourth and 3.08 axle ratio. it turns 1800 rpm's at 60-65 mph and gives me 16 mpg+. it could use more low end grunt, but i usually can get out of most situations by putting transfer case in low.
i am looking to put zf 5speed in, which will give granny low first and overdrive. this may be a similar approach that would satisfy your needs.
hope this input helps your decision.

 

Quick question for you. What year model is the truck?

The transmission that is in the truck now will bolt up to a 302 or a 351 with no changes.

on mine I left the stock 300 I-6 fuel efi fuel pump in place, and everything works fine. Now, on a carb swap I have no idea, but if you're running efi now, you might have to change over to a regular engine driven fuel pump due to the psi levels of the efi pumps.

1988 F-150 Custom to XLT Lariat conversion, 5.0 EFI (formerly 300 I6), 5-speed M5OD, 3.08 rear gears (will be upgraded to 3.55's), Summit headers, Flowmaster muffler W/ dual 3.5" tips 24" long. Caution Customizing in progress, Watch for flying tools & Parts!

 

Ya I was thinking of swapping gears too but I think I need to keep what is in there for towing, which is mostly with a 3500# trailer, and sometimes a 7000# trailer. I just don't want to decrease the mileage as it is. Stock with the I6 I am getting 10-12 mpg, pretty crappy in my eyes. I would be satisfied with the same mileage if it was an 8 in there. Anyhow, my truck is an 88, forgot to include that. Ya, I know the fuel pumps for typical EFI systems output much higher than mechanical carb pumps, but I didn't know if there was a great difference in pressure between the V8's systems and the I6's systems as far as EFI is concerned. If only there was a 5 speed that would enable heavy torque multiplication in 1st and 2nd, but offer a shallow 4 and OD for higher speed cruising and economy...without having to empty the wallet...

 

These were posted a while back (july 2000)

On my 88 I did the engine swap with one from a 91 model F-150. But I had to use the wiring harness from an 87. The six cylinder fuel pump works just fine, even though it puts out more pressure than the 302 needs. But I get between 13-16 with mine, of course that's with 3.08 rear gears. But I will be changing those out with 3.55's in the future. But the mileage I'm getting now is much better than what it was. Between 10 & 11 was what I was averageing (sp?) on a constant basis (whether it was city or highway.)

I hope this helps.



Mazda M5OD
3.39:1 (Reverse), 3.9:1 (1st), 2.25:1 (2nd), 1.50:1 (3rd), 1:1 (4th), 0.8:1 (od)

ZF S5-42 Close Ratio
3.79:1(Reverse), 4.14:1 (1st), 2.37:1 (2nd), 1.42:1 (3rd), 1:1 (4th), 0.77:1 (od)

ZF S5-42 Wide Ratio
5.24:1(Reverse), 5.72:1 (1st), 2.94:1 (2nd), 1.61:1 (3rd), 1:1 (4th), 0.76:1 (od)



You can always tell a Chevy owner, You just can't tell them very much.