Yeah I'm on my iPhone so signatures don't show .
My cab and chassis has a zf -3.55 gears and it will tow heavy stuff but you really got to get into the throttle and rev it if you're on a big hill , sounds cool (460ci) but sucks fuel !
If your engine has a better cam then I'd go with the richer carb setting , after all a " stock setting" on the carb with a slightly warmed engine doesn't work :-)
I really enjoy the collective knowledge on this thread which is one of the reasons I " subscribed" to it I don't even own a bullnose lol .

 

Damn, all this discussion of towing, 3.50 gears etc. You guys make me think I'm doing something wrong. My old F-150 had 3.25 gears in the 9" rear and towed quite well with a C6 and 390. My F-350 did great with a 10,000 lb 5th wheel and the stock 460, C6 and 3.55. Coming over to the Eastern Shore last Saturday towing my Aluma trailer loaded with a bunch of fence panels I only had the E4OD come out of OD once, that was climing the up slope of the first tube on the CBBT at 40mph. It still took over 3/4 throttle to do that.

 

Actually, somewhere buried back in the over 100 pages of this thread there's a discussion of my efforts to find the right jet/rod combo to lean the stock jetting some. My E'brock AFR meter was showing that it was running slightly rich and a burble at part throttle suggested that as well. Unfortunately, E'brock doesn't sell a jet/rod combo that is less than 6% leaner at cruise, so I found a combo in a Carter Strip Kit that got me ~4% leaner at cruise, but also leaned the power mix significantly as well. That's what I'm running now, but may go back to the stock 1406 jetting, which will perk the engine up a bit and may still turn in about the same MPG in real-world driving as opposed to the no-wind, light acceleration, and 62 MPH driving I was doing for testing.

As for heavy throttle sucking fuel, see my comments in the response to Bill, below. And, I agree with you re the collective wisdom - a bunch of really bright people have signed onto this thread, which has really helped me.

That much throttle can't be good for economy, although I doubt "economy" and "460" deserve to be in the same sentence. Anyway, my understanding is that there's a balance between a lot of throttle (as shown by low manifold vacuum) in a tall gear, and higher RPM with less throttle. I think that's what we are talking about - where each engine is most efficient with respect to RPM and throttle. Knowing carburetion as we do the act of opening them up to 3/4 throttle causes a lot more fuel to dump into the stream. Obviously EFI doesn't always do it to the same extent as it is mapped to provide an optimum mix - at least it was when the engine left the factory.

So if you drop a gear and let up on the throttle, does that increase the MPG? I wish I knew. I think the only way to know is with one of the MPG meters like I once had in a CompuCruise. It had a flow sensor on the fuel line and a pickup on the drive shaft so it knew fuel flow and MPH and could calculate the MPG quite accurately.

 

Gary, I was actually seeing how much it would take. I was maintaining speed at 40 in 4th without downshifting. I could actually see some increase on the tach before it dropped to 3rd. BTW, the E4OD program for the big block is pretty conservative as far as it stays in lock-up from second gear except during shifts which gives it a weird felling "double shift" sort of like the old Hydra-matic 4 speeds going from 2-3.

On the second tube I was going closer to 45-48 and I accelerated just fine at about 1/2 throttle. Yes, fuel economy and 460 are like Military Intelligence, sort of an oxymoron. I had a CompuCruise in my 77 till it died. It was a neat toy to play with. That truck got 16 mpg on the highway with the 390 and C6.

 

In all fairness to my chassis cab , it's got an 11' utility body on it and weighs 9500lbs by its self . The trailer had a 1975 f250 camper special , with 4 small block for engines a few aods and a 22re in the bed .
Needless to say it was grossly overweight and shouldn't have been on the road . If I was going to tow with that truck on a regular basis I'd put 4.10s in the rear .
390-460 both have a lot more guts then a 351m .
That being said I think that for what you use your truck for Gary you've got a great combination !
Cool thread , great people with lots of experience to bring to the table , that's why I'm sticking around .

 

If you run across a CompuCruise I'd like to have one. It could answer a # of questions I have.

Yep, I think the combo works pretty well. But, I still have the original 351M and instead of 4:10's I might go with a 400.

Now, for what I did today. I pulled the motor and resistor out of the heater box to see if there were some leaves. Sure enough, there was one directly against the resistor, as shown below. And, having seen my father's handiwork in the form of a hole drilled into the bearing on the motor I decided to swap it with one of my spares. I got it on, and since the gasket wasn't good I used a bit of RTV to seal it. Imagine my chagrin when I discovered that the 81 (and earlier I assume) wiring is different than that of the the 82's (and later I assume). In the last shot you can see the adapter I made that plugs into the truck's wiring and into the motor's wiring. It works, but I left things so I could go back to the original motor if I wanted.

And, an oddity - the wires to the motor I took out were reversed. In other words, the wire colors swapped at the connectors. But, since one is female and one is mail you can't just plug them in backwards. So, I don't know what happened. Maybe this is a replacement motor and whomever rebuilt it swapped the wires?

Anyway, after that I turned to the brake that was dragging. Sure enough, the driver's side rear drags at one point in the rotation. I've backed the adjustment off 4 clicks and it still drags a bit at one point. So, it looks like I'll put the dial indicator on the axle to see if it is bent. And, if not I'll either try a different drum or have that one turned. Thoughts?

 

Are they oem drums or aftermarket ?
Every aftermarket drum I've gotten brand new was out of round !
I used to sell autoparts and you won't believe the amount of new drums that are out of round , either from shoddy machine work or shipping ?

 

OEM. I have drums off an 82 and an 85, both of which I've parted out. I had another set turned, for next to nothing, for another 82 and the guy told me they had lots of meat so could be turned with no problem. If the axle runs true I may just have a set turned.

 

I doubt the axle is bent but anything is possible I suppose .
Getting the drums turned is a good idea anyway ..

 

Don't worry Gary, my heater wiring is the same deal. Unfortunately for me, the previous owner cut the connectors off on the truck side for whatever reason, and then covered the ends with house caps and electrical tape.

Napa should still sell the factory terminals, and any junkyard can supply the factory connectors.

 

I may go to a salvage to get an 81 or earlier motor so I have the proper connectors and tie them to the later model connector I pulled off a spare harness I have. That way I'll have an adaptor with factory connectors, which lets me run the blower motors I have with no worries. On the other hand, if the motor is good.....

I thought I was going to take the motors apart, swap to the connections, lube the bearings, and put it all back together. But, I haven't figured out how to take them apart! So, for now I have something that works and will have to suffice.

 

Gary, I haven't seen you post on the "what have you done to your truck today" thread so I thought I'd just post this here so you can see it here lol.

I drove my truck about 7-8 miles today, the fuel gauge didn't move much, it's doing better on gas but still bad, and ever since I adjusted my vac advance pot for more advance I get a ping on re start occasionally and sometimes a light bounce back agents the starter, my initial is at 12* BTDC, haven't had a bounce back agents the starter before I adjusted the vacuum advance pot, might back it off a couple turns, sorry for the hijack lol.

I have yet to check the fuel PSI, but will do in a couple days.

 

I responded in WHYDTYTT.

 

That explains it, that confused the crap out of me lol

 

I ordered tail lights from O'Reilly's today: One Glo-brite for an 81 and one for an 87. Supposed to be different sides so's I can test them. Should be in Friday, but don't know if I'll get to try them out until next week as I'm working on the kids' Pacifica. Hope to take a few pictures and let y'all see whatever differences I can see.