Got my 1979 F-250 running good. Had new exhaust (headers back) installed yesterday so I’ve been tweaking my idle and EFI settings today. This evening I made three 0-60 MPH passes just to see what it would do. Averaged right at 13.0 seconds using my iPhone and calibrated eye on the speedo which I verified to be accurate with GPS. Here’s what I’ve got:

1979 F-250 reg cab 4x4
unknown year 460 (70s vintage swapped in by PO)
C6
4.10s
35” MT tires on 16” steel wheels
5-6” lift
Custom flatbed
35 gallons of fuel in tank
toolbox and full-size spare
??? curb weight (it’s heavy)


Info on the 460:
Atomic EFI
Headers
2.5” from headers into single 3”
Big turbo muffler
camshaft unknown (assume not stock)
stock heads

I had no idea what to expect but the truck feels strong especially in the 2500-4000 rpm range. It shifts at 4000 rpms both 1-2 and 2-3 at full throttle so I don’t know if it will keep pulling up to 5000 or not. I have rev limit set to 4500 on the Atomic but due to trans I can’t get there.

There’s no point to this post other than just an FYI if you were looking for a random data point for a heavy truck with big tires and a 460.

 

Not bad, I would guess your weight of the truck to be pretty close to 3 ton.

 

Beds tires and bumper make a big difference in weight. A 150 pound bumper 5-600 extra for the bed 25-50 pounds for the wheels comes to 750-950 in just accessories not to mention that 100 pounds of tools ain’t much when you got a shovel, come along, set of wrenches and sockets.

Very cool truck! Love the colors and it pulls those wheels of nicely

 

35 gallons of fuel alone is 212#

 

Thanks! I can’t take much credit as the PO did the lift, wheels and tires. I added the full size spare and tool box and have done a ton of work to get it running good. It would barely run and would not shift when I bought it and I assumed a rebuild or new engine and trans was in its future. Turns out the 460 is pretty healthy. Oil pressure is 70 psi cold and 50 psi hot at 2500 rpms. 25 psi hot idle. That’s with 15-40 Rotella. Has a few oil leaks but doesn’t burn much if any. I was down a quart after 3000 miles but I’d say that’s acceptable in my mind. Runs cool even on hot summer days it stays at 195-205F. The VB in the C6 was bad so I swapped in a used one I bought locally and it shifts great now.

The paint is original and had a lot of oxidation when I got it. I spent several hours with a polisher and some medium compound and it shines nice now. Looks good for it’s age I guess.

I want to put it on a scale but I’d guess it’s in the 7000 lb range as it sits. I guess the fact that I can pull off 8-9 mpg if I keep it at 65-70 mph is decent. Speedo is accurate but odometer is off by 10% so my actual mpgs are better than they seem.

Also just in case anyone is considering the Atomic EFI system I would not recommend it. There is minimal user tuning options and no data logging capability. Basically AF ratios and idle speed are the only adjustments. Not sure what other TBI kits are out there but I’d look at something else if I was in the market. I got it running good but idle quality and starting have been my main challenges.

 

Sweet truck! I have a 150 the same color, you’re the only other truck I’ve seen with the same color scheme! Glad you got your paint fixed up, mines pretty badly oxidized rn.

 

Thanks! The polishing made a huge difference. I just bought a cheap polisher off of Amazon and got some medium compound at the local auto store. Still has character but looks nice and clean too.

 

From a glance, I can't find much on further tuning of the atomic efi, I don't think there is.. if you want to keep a TBI setup, from what I've heard, the holley sniper and terminator systems seem to be good, although I have no direct experience with them..

Are you shifting the trans manually or just putting it in D and letting it do its thing? I had to manually shift my 78 if I wanted that c6 to shift past 3500 rpms..

Nice truck, gives me motivation on reviving my ole pile of a truck lol

 

Good info, I’ll give it a try, why not haha. Thanks for the help, I appreciate it

 

Yep, in D at full throttle it’ll only rev to about 4000. I can manually shift and rev to the limiter on the Atomic, but I’ve only gone to 4300 or so just to see what would happen. Probably not worth blowing the engine just to see what she will do...I keep telling myself! It will automatically kick down into 2nd at speeds up to 65 MPH and will hold 2nd up to 75 MPH if I keep it on the floor. It shifts good under part throttle so I’m pretty happy overall with the C6. Only wish it had an OD. Living with 2800- 2900 RPM at 70 MPH right now. Probably would be ideal at 2200-2300 RPM but gaining that OD will be quite a project. I’d go with a ZF5 most likely.

Agree that the FI Tech and Holley systems seem more advanced. If I were to buy one I’d go with one of those. The PO of this truck installed the Atomic so I’m just working with what I’ve got. I actually have it starting, idling, and running good for the first time since I’ve had it. I could always get 2 of the 3 but not all 3 at the same time. Still only averaging about 7.5-8 MPGs but that doesn’t seem too horrible. I’m also thinking if I buy an ignition box and new distributor I can let the atomic control timing electronically and it would be more tunable. Just not ready to spend that much $$$ yet, it won’t be cheap.

 

Nice man, that's about where my ole 78 was at 70, it has a c6 and 203.. it's been sitting derelict for about 12 years now, but I have an efi 460, zf5 and 1356 i took out of a 90 f250 early last year, and I'm gonna swap it in.. I'll be doing a thread on it when I make some more progress..

You could go the sorta factory efi route, the ford efi is pretty adaptable to anything, it's a basic setup.. I'm going with megasquirt, for now I'm going to keep the ford tfi, I plan to do ls coils later on, which is pretty easy to setup.. you could find the rails, sensors and harness at a junkyard, and use either a factory style throttle body or a 4bbl one without injectors..

Just food for thought.. you have a great start for a project!

 

That’s awesome! I’m interested in how the ZF5 swap goes. I found one locally for $100 but it has a chunk missing from the top of the bell housing so I haven’t bought it yet. Also nervous about get a clutch setup with pedals and hydraulics since I’ve never messed with anything like this before. Good news is that’s it’s just a project truck so if I screw it up I’m not stranded, but I do like to drive it a lot so I want to keep the downtime to a minimum. Looking forward to your swap info when you go for it. Good luck!

 

For sure man, I'm going with a universal clutch master cylinder, keeping the clutch hydraulics, way better than mechanical linkage.. I have yet to get a pedal assembly..

Only thing I'm a bit unsure about is how the zf5 will bolt into the frame, as far as having to move the crossmember or not.. I've read it's really close to a c6 and that it's not, and that some have had to modify the transmission tunnel.. I guess I'll find out lol

 

My crossmember has already been moved once when the PO swapped in the 460 since the truck originally had a 400. I’m guessing the bigger 460 required it to move back some. I’ve also read that a ZF5 should be pretty close to a C6 and some have been able to use the factory driveshafts. My luck everything will be off just enough to cause a lot of work! If I run across the swap thread I found I’ll post up a link.

 

Keeping me inspired.