Running/stumbling/backfiring

[Gypcmechanic]

Ok so I broke down and rebuilt the carb on my 73 F100. It was really running badly. It had a bunch of crap in it. So got it back together but it still wants to stumble a little if it's loaded or if you try to accelerate quickly above 60 MPH it stumbles and backfires. If you stay in it it keeps doing it. If you accelerate gradually it tends to be ok. It has a new distributor but still has points. It won't run at 6 degrees of timing I have it at about 12 degrees. I'm wondering if I need to bump it up a few more degrees. Also it gets a little hot when it starts acting up. It has new heads on it as well. The backfiring could be leaning or timing. I live at 4000 feet. It has a 360 2 barrel. Any ideas? Doesn't seem to have a vacuum leaks either. It starts and idles great. Also checked the advance/retard and it seems to working. I know I need to dump the points but budget constraints are stopping that for now.

 

[Workin' Rig]

Definatly sounds like timing, my LTD did the exact thing before the chain jumped...

 

[Gypcmechanic]

SMH. I didn't think about that. It's really quiet though. I've heard loose chains before but it kind of makes sense if the cam is jumping around. I'm gonna try and baby it for awhile. This was a barn find so I have been driving it and need to take a break from spending any more money on it. Thanks!!!!

 

[Workin' Rig]

Mine was quiet to.

Im not sure if the FEs used the fiber gears like the windsors, but it may be a good idea to not drive it if you can, if the chain goes youll pry bend valves and pushrods (like i did)

 

[Gypcmechanic]

Um, ok. I feel like an idiot. And the bad thing is this is not the only vehicle I have with points ignition. I got lazy. When I put the heads on I also bought a reman distributor. Well, the thing that was getting me was in the morning on the way to work when it's about 20 degrees outside it ran great even loaded going uphill. Then as the day warmed up it started it's stumbling backfiring etc. So here is the dumbass part. When I up the new distributor in I (dumbass) didn't bother to check the gap on the points. Can anyone guess what was wrong? The .017 feeler gauge was like a hotdog down a hallway. So the dumbass regapped them and low and behold it fixed it. I can shift into fourth at 20 MPH at it pulls right along. So now does anyone have any tricks to improve gas mileage?

 

[Gypcmechanic]

I love this forum. Everyone is very helpful.

 

[Workin' Rig]

Yes, it is by far the most helpful truck forum out there.

As far as mileage, keep your foot out of it is bout all i can tell ya.

 

[Fellro]

FE's aren't really noted for mileage... The typical though, free flowing exhaust, maybe pipe a bit of fresh air in from behind the grille.

 

[smokey]

Its the simple stuff that gets you every time. Glad to hear you got it figured out.
Bought cheap points at a swap meet one time they would melt in less than 20 miles. That stumped me for a little since they were new. I bought 6 of them for in my dual point distributor.

 

[tjcustomranger]

A lot of people said a square or spreed bore 4 bbl carb will improve it that's only if you keep your foot out of it.
The 390 seems to get better mileage than the 360
Headers and good dual exhaust somebody also told me a nice set of aluminum heads would help mileage. I'm not sure. He sai he could get 12-14 out of them.
My dad has a 69/72 ford highboy with the 390 and he can get 12.

 

[Gypcmechanic]

Yeah it seems that it's a really big engine to have a 2 barrel carb. I would think letting it breathe would help. I may have to sell it and get something better to commute with. I don't want to though. I would love to put a fuel injected 302 and a 5 speed in it. It's in awesome shape for a 73. Plus where it's been they don't use car dissolver on the roads in the winter. We just drive on the ice and packed snow.

 

[tjcustomranger]

I've thought about getting a smaller truck for a dd or getting a smaller engine for mine but I can't seem to let it go. I already had to get rid of 2 of them one a 73 the other a 74.
Hopefully I can find a nice little commuter soon