Posted this in the new section yesterday. Probably belongs here

First post here. Thought I'd look around for a place to share ideas and solutions to Mustang problems. I have two (new to me, been in the family for 25 years) Mustangs. They are both 1970's One is a Mach 1 Red on black with a 351 CJ from a 1972 Mach 1 and the other is a convertible white with black top and also has the original 351 C in it. The cars are in great (not show but close) condition. I do have an issue with the Mach 1 right now and probably need to be directed to the right area in the forum for engine troubleshooting. Seems the Mach will idle and rev nicely all day long, as long as you don't drive her too far.I get a couple miles down the road and she dies on me and won't get going again until she's cool.I have replaced the carb with a new Holley and replaced the fuel filter and coil. The ignition will be next but I still can't figure out why at rest the engine will run great but under a load she quits. Any ideas?

 

probably should have mentiond that the pics are what they looked like when i picked them up. They have been garaged for 25 years and driven about 600 miles in the last 10 years. They are a little cleaner now.

 

Nice rides!

Kinda sounds like vapor lock.
Dont know if the pict of the engine is the culprit car or not, but the fuel filter sitting on the intake may be heating the fuel up to a vapor before it reaches the carb.
My grand dad was a boat guy and we had that on a boat he built.
I swear this worked so bear with me, he put OAK wooden clothes pins on the fuel line and it ran great the rest of the weekend.
He told me it pulls the moisture out or the fuel. After we got home he ran some new fuel line that was not so close to the block problem solved.

I could be wrong but worth a try.

 

Yeah I thought Vapor lock too. That filter is long gone and repladed with a metal fram. i thought it might be the auto trans kick down but I don't know. Someone suggested that the distributor might be loose and advancing on me but why would it correct at cool temps? i think it's the ignition and will probably replace the points with electric tomorrow. Couldn't hurt. well other than time and money and we all got plenty of that right?

 

1) Welcome to the forum
2) You lucky SOB, not 1 but 2 nice cars

Take this for what its worth, I am only running the original I6 in my 66 but I had a similiar problem. She would run great 10-15 minutes then die, she would restart after sitting a while. Everyone said vapor lock so to test that I checked to see if I was getting fuel into the carb when she would not start. There was plenty of fuel so that ruled that out.

Next we replaced the coil. Same problem, same time frame.

We got her started let her die and checked for spark. There was no spark when she died. We traced it to a bad connection on the wire from the coil to the firewall. There was a male/female connection on the wire (I have no idea why) and somehow the connection failed when warm and worked when cold. Replaced the connectors and havn't had a problem with it in months.

 

Is that the original carb on it? Here is something I actually remember from 1972. Certain ford V-8s had a tendency for the carb to loosen up for no particular reason. I personally had it happen on a Galaxie or some such full size 72. Cruising on the highway the car would start to sputter under load, like going up a hill. It would eventually just die. When the carb cooled down it would start again.The fix was to simply tighten down the top of the carb again. Strange but true. It's a long shot, but you could check it out.

 

drop off the title and the keys at my house, problem solved.
+1 on vapor lock, my 66 suffered the same problem

 

Thanks for the ideas and help. The carb in the pic is the old carb. I put in a new Holley 600 cfm and new coil. The grounding wire sounds like an easy fix and I'll start there. I haven't been able to duplicate the problem in the garage so it will be dificult to check fuel supply for vapor lock unless I break down in a convienient spot. The ignition is where I'm going. The plugs, points, wires, haven't been replaced in 10 years. Also I noticed that the distributor cap had some play in it. Not sure if the ignition is the problem but it needs to be replaced anyway. Is it an easy conversion to go from points to electronic. It's been about 20 years since I worked on my cars so my memory is not all there.

Here is a pic of the cars in their new home

 

I went with Pertronix and was a very simple, easy, fast switch.

 

Went with petronix easy install made a big differance but after about 40 minutes she died again. Also changed distributor cap, coil, wirers and plugs. Can't figure this out. Got to be a vapor lock or fuel problem. New carb too.