I believe it's the same carb, but call Summit to make sure. Or call Edelbrock. They bought the rights to the carter design.

 

Yeah I knew that didn't know if the bodys and designes where that close but they are I called guess ill start there

And with the tire sizes and rotating mass could I use aluminum rims with the biger tires or just use them with the stock size or maybe a set of 265/75 r16

 

Gearing is your problem. Granted with that wee little 351 4.10:1 gears are great for running anything but empty. Regardless of gearing you'll be around 10 MPG around town, with good jetting and timing you can probably squeeze closer to 12. You may try an adjustable vacuum advance and use manifold vacuum. It will get you max advance at loight throttle but drop off most or all of the advance when you start to get into the throttle, which is what you want to avoid detonation. The more timing you have the leaner you can run. You should be looking at about 34* mechanical at 2500-3000 RPM and another 10* of vacuum on top of that at light cruise. You'll have to adjust this for your particular engine/load/driving conditions.

If you drive a lot of highway though, you need an overdrive gear it'll drop about 500 RPM at highway speed and add a couple MPG without changing anything else. More money and work but absolutely worth it, every truck I've owned has got a ZF5 swap.

 

I would focus on the carb and timing for now. The gear ratio change out and overdrive both cost a small fortune, unless you do them yourself, even then it is pretty expensive.

Just make sure every drop of fuel going into the motor is getting burned as efficient as possible. and then keep your foot out of it. Also, doing a fresh tune up with all new wires and plugs and cap and rotor, the regular stuff, tire pressure, fluids, a good alignment. All those contribute to efficiency.

 

I have a rear diff in one of my 2wd parts trucks its a 90 that was a zf5 ill have to check the ratio on that that should be a shorter gear right? Just leaves me to find a fornt gear set

Right now I'm running 12* intail and I have a slight ping with 83 octane I'm thinking that a 180* thermostat and a adjustable advance can will most defentaily take care of the ping

 

Most all 4x4 f250/f350 trucks 80 thru 97 had either 3.55 or 4.10 gears. That's pretty much all you are going to find out there. The 2wd's had a few more choices, but of course you would not find a matching frontend. These trucks were designed for work when the speed limit was 55mph. Notice as you get in the later trucks, overdrive came into play making them more versatile. That's why many people with the early trucks swap in the later overdrive trannies.

 

My overdrive drops rpm by 650 on the highway. Less engine wear as well.

 

My 82 F250 2wd 351W(2bbl)/C6/D60 w 3.55 gears gets 10-11 in my commute. Running 265/75-16 tires. The first thing I would do on mine is an OD trans as I am at 2500 rpm at 60.... I would go straight to an E4OD if it weren't for the electronics to run it. Maybe a built AOD...

 

How much electrical is involved in a e4od swap any more work then a zf5?

 

You would have to get a stand alone computer for it i am thinking, and they are pricey. You could get taller tires, tall and skinny. I have 33" tall tires with a np435(no OD) doing 65 mph i am only at 2100 RPM's.

It would literally take years of consistent driving for a OD tranny to pay for itself. If you get an extra 2 mpg, and that is IF, you may save up to $500 on a vehicle driven 10,000 miles per year. Even with an OD tranny, you wouldn't get a consistent 2 mpg increase overall, you will probably only realize that increase on hwy driving.

Not trying to sway you from an OD tranny, just saying it can be alot of work for not alot of payoff, just something to ponder before you take the plunge.

 

33" tall tires doesn't tell me much. Can you give the actual tire dimensions, metric or English?

I'm running P265/75R16 and hitting about 3k at 65mph. You must have a *very* low axle ratio to be doing 2100rpm @ 65. AFAIK, the NP435 has the same high gear as my T19, 1:1!

I'm curious what your axle ratio is, as 2100rpm in high gear seems very unrealistic short of an overdrive or super low axle ratio. But I know 2wd vehicles can get quite low in axle ratio, hence my question.

BTW my 460 turning at 3,000rpm going 65 on the highway turns 10.1 mpg (60 miles each way commute). Granted that's probably an ideal highway commute, so on a 351, I wouldn't consider low teens to be all that bad.

 

your 265's are about 31" tall, mine are 33x12.5 or 305/70r15. My gear ratio is 3.55, i am guessing you have 4.10's or 4.55's? and yes, the final drive on my tranny is 1:1.

I didn't realize you had the 460, i don't think you are going to improve much upon your 10 mpg. maybe if you rob a fuel injection off a later model you can get it up in the teens, maybe...i guess you have 2 trucks.

I just installed a 500 CFM eddy on my 351w that is mildly built and it runs just fine, doesn't quite have the get up that the 750 did, but is more driveable. Haven't had it on long enough to get any mpg numbers, but am hoping for the best.

 

You need a tall but narrow tire like a 215/85 r16 I guess slightly taller then the stock and narrower

 

It's a true statement about the overdrive swap not paying off unless you drive your truck a lot and put many miles on it. I don't put many miles on mine, but I did it anyway and glad I did. Besides the extra mpg, it's so much quieter on the interstate, and you can relax and enjoy keeping up with modern traffic. I believe some of you are like me, and can't stand the engine wound up so tight trying to keep up with traffic.

I did a lot of research before I did my swap. The E4OD was a option, but if you don't get one that was already rebuilt, then you will probably have to rebuild it before you put it in, and it needs a lot of updating if it's a tranny that was made before 95. They had a lot of trouble with this tranny, and finally got most of the bugs out by 1995. And it will need a controller to run it, they are about $500-$600. Figure about $1500-$1800 for the tranny rebuild.

Another option is a add-on overdrive unit. Not quite as good as the E4OD, since if you have a c6 you will still have some torque convertor slip, but these units give you some interesting options, like shifting it in and out giving you more gear choices. This would be the ultimate choice with one of the old 4 speeds, you could split the gears and have 8 speeds. But they are very expensive, around $2500-$3000. And then you have the driveshaft modifications.

The option I chose was the zf 5 speed. It was the cheapest way to go. I looked around, and most junkyards want at least $750 for one, higher for a rebuilt one. What I ended up doing was buying a wrecked donor truck with the zf already in it for $1000. Seemed like a lot for a totaled truck, But I got the tranny, the flywheel, the clutch master and pedals, the driveshafts and crossmembers, the wiring harness to the tranny, and the floor plate. Everything looks factory except I didn't swap out the steering column, but I could have if I wanted to. I was then able to sell off the transfer case, the c6 tranny out of my original truck, the aluminum wheels that were on the wrecked truck, the wiper motor, etc. Each time I sold something, the price of the swap went lower and lower.

 

You did it right franklin. If you want to make it happen that is the way to do it, and if you're commuting 120 miles everyday, then the zf5 swap would be the best option IMHO. The gear splitter is really expensive.

I knew a guy who put a gear vendors behind a NV5600 behind a cummins in a suburban with 3.73 gears and was getting 36 mpg hwy! he was turning 1300 RPM at 65 mph, it was a nice setup.