Hey Guys, great forum here with alot of experience and ideas

Im a noobie to this forum but Ive had alot of old vehicles and enjoy finding them, researching and working on them. I live in eastern Canada...New Brunswick ( we had snow here last night-winter is back..)

I bought a 66 f100 a couple months ago.. a sweet little short wheel base 352 three speed. It came from South Carolina a couple years ago. great condition and completely original except for aftermarket rims and tires

The motor was tired , so I completely rebuilt it,put a mild comp cam in it while I had it apart , very mild , just a little above stock ( I wanted to keep the original intake and 2 barrel ,so no need of a big wild cam )

so heres my dilemma
I have a stutter..stumble or hesitation just above idle when driving slow or pulling away from a dead stop. I have replaced the carburator with a reman. I started out with a kit in the original but I still had the problem so I replaced the complete carb...still didn't cure it...I have checked a few times for vacum leaks...none. I installed a pertronix module,coil and new wires while I was re-assembling.. re-checked the wiring a few times..tested the coil..over 12 volts at start up..everything looks fine..gapped the new plugs at 035.
heres another twist.....in order to get the engine running close to where it should, I have to have 40 degrees of timing...( crazy..I know ) but that is where it has to be, just back a bit from starting hard and spark knock. When I pull away and get over a quarter throttle, everything works fine and the motor pulls strong..I have replaced the fuel pump and fuel filter as well
any ideas would be greatly appreciated. I have read hours and hours on this forum but I thought I would explain the situation and see what you guys can suggest
Thanks in advance for any help or ideas

 

advance in the dizzy working as it should vacuum and mechanical ??

 

Welcome to FTE Toys,,, I would start with your dist, and check and make sure you are at TDC and on #1, sound like you could be off, is your advance hooked to ported or manifold vac.? Should be on ported.
I would also check your cam/timing marks, (if you want to go back that far) it could be off a tad, I had a 352 I did the same thing to, even after checking three times ( I thought!) I was off 2 teeths, thankfully nothing got hurt.

 

I tested the advance in the dizzy with a vacum pump, everything worked fine..vacum connected to ported . I checked the whole #1 on top of compression stroke ,rotor pointing at #1 a few times.,..its on as well..

I think my 352 is posessed..

 

see how much vacuum the engine has while running

 

If you still are using the manual choke, have you checked to see that it is open all the way and the floats are not sticking?

 

I tried the vacuum gauge today and it is from 0-15 and the needle is fluctuating so fast that I can hardly read the gauge.. I pulled the PCV out of the valve cover and the vacuum is pulsating like crazy.....????

 

check for internal Intake manifold leak, and also sticking intake valve also leaking head gasket..

 

sounds like a valve hanging up or not opening

 

You nailed it Jack....I took the valve cover off the drivers side and found a bent ,disconnected pushrod and a valve hung open. I can't believe this in a completely rebuilt engine and I can't believe how smooth the engine ran on 7 cylinders ,once it was above the sputter
Thanks again for replies,help

 

Thanks for letting us know,,, I was thinkin about it last night,,, then I read about the vac. gauge,,, YUP! Good Call Jack!