I have a 70 F100 with a 360 and my issue is that it is a dog.....has pulling power but no get up and go what so ever. I blame alot of that on the fact that I have been driving new vehicles....mainly a dodge hemi for the last 5 years but even still I have a road that is easily a mile long and its all I can do to get to 70mph. I was told that the vacuum advance that is on my engine is a "governor" type. I have checked to see if it is working and it does but it does not move very much. I have timed it using a light as well as adjusted the carb and put a vacuum gauge on it. To describe the existing one it has 2 ports coming off of it. ! is hooked to the vacuum line going to the carb and the other has a screw in it with a plug over it. I purchased a new one today from napa and the directions says that it is adjustable.....I have read posts about people doing this and recurving their distributor but I am clueless in all this. I just want to make sure I am getting what I am supposed to out of her, she is not a race truck by any means. But if anyone has any advice on this that would be great.

 

Vac advance was designed for driveability, at cruise and part throttle operation. Lack of power can be a lot of different things, including problems with distributor advance, but vacuum advance is not one of them.

If the engine has a few miles on it, a new or remanufactured distributor would be a good plan in any case. What did the vacuum gauge show for vacuum at idle?

 

Gauge holds steady at 18. I also added the pertronix ignition and really havent noticed much of a difference, guess I expected more from what I read about it.

 

That's good vacuum indication, signaling a normal engine. Dumb question, but have you checked your brakes for dragging and silly stupid stuff like that?

My 64 was real doggy - had installed a new Holley carburetor, but failed to ensure that the throttle plates were perfectly vertical when accelerator was floored. Simple (and common) mistake, and really kills power.

Since you have a timing light, check to see that your mechanical advance works properly and your total (initial + distributor) is 36 - 38 degrees @ 3000 or so rpm w/ vac advance disconnected and plugged.

 

I dont have a tach and I guess i dont have one of the fancy timing lights that tells you your rpm. I will look down the throat to make sure the butterflies are completely open. Is there any other way to check the mechanical advance other than taking the vacuum line off carb and sucking on it to see if it moves? I did that on the one thats on it now but it did not move much at all

 

No, mechanical advance is separate and distinct from vacuum advance. Initial (crankshaft) is what most people think of when timing is refered to. Mechanical advance is a system of centrifugal weights and springs, based solely on RPM. Vacuum advance is load dependent, based on engine vacuum.

I wouldn't focus any attention on vacuum advance at this point, has nothing to do with the poor acceleration. Forget about that for now. If you have a vacuum gauge you can use it to set your timing, might be worth a try.

A tach is necessary for accuracy but for ballpark troubleshooting all you are looking for is an indication that the weights and springs are not gummed up and such, and so providing sufficient advance in the right amount, at the right time.

Put a light on it and rev it up, (basically) make sure it advances to 35 to 40 degrees BTDC w/ vac advance disconnected. That is your "total" timing, initial plus mechanical. The vacuum advance would add another ten or 15 degrees at cruise, for a total total of around 48 degrees BTDC.

You mentioned Pertronix. They are excellent product, but a worn out, gummed up distributor cannot be compensated for. A replacement distributor is the best bang for the buck around, if that's the case. They wear out fairly quickly, maybe 50 or 60k miles?

 

Well I appreciate the advice....I will try and either get an aftermarket tach or borrow a different timing light to try and see if my distributor is doing what it is supposed to

 

No problem, but a regular timing light will work fine.

What you are looking for is 35-40 degrees indicated on the damper at 2500 to 3000 RPM... Maybe at a higher RPM if stock springs installed. Given the symptoms you mention if there is a problem in the distributor or timing it will be obvious if there isn't enough advance, tach or no tach. Make sure to disconnect and plug vac advance when doing this check.

 

When I first installed my Pertronix III with Flamethrower coil, I had to advance the timing to almost 30 deg at idle. This was just to get it to run. I bought a reman dizzy, and now the timing is spot on at 12 deg with 38 deg total advance. With the hotter spark, you can widen the spark plug gap. Good luck.

Kurt

 

If your truck still has the stock exhaust logs, getting rid of them can also be a huge improvement.

 

"I have a 70 F100 with a 360 and my issue is that it is a dog....."

Given the advanced age here, you may have some wear issues, but your vacuum number is good so it can't be too bad. The fact is, the 360 made barely 200 hp and low 300s torque. You can wake it up a bit with headers and a small 4bbl, but you can't to anything about the low compression, sunken piston and modest cam without digging deeper into it.

If you do that, you can dial up the power fairly easily with little penalty at the pump.

 

The OP indicates that he can barely reach 70 mph in a mile, doesn't that sound like a problem or is that typical for this particular engine platform?

 

Sounds like a problem to me too......mine wasn't a hot rod by any means but it could get up to speed no problem......

 

To describe the existing one it has 2 ports coming off of it. One is hooked to the vacuum line going to the carb and the other has a screw in it with a plug over it.

I think having the second vac hose capped may be restricting the movement of the advance system. I think that is the hose that goes to the back side of the vac advance canister. With it capped, it might be holding the advance back.

I think I have read that you can run with that port open to the ambient air without causing problems.

It would be a easy test to see if it makes any noticeable improvement.

 

Sorry guys. Been working on ac stuff on the truck all day but did manage to check a couple things...
Butterflies do open all the way on the carb.
Put the timing light on her with hose unplugged and capped off and raised the idle as high as I felt comfortable with without knowing the rpms and my timing was at 18 degrees. At idle it is at 10. I will be working on ac tomorrow as well but hope to try and get something to see what my rpms are while checking. I have not changed plugs or wires yet just since it does run well....other than what we have discussed.
Oh and it does have headers. I do have a performer 390 to put on it but no carb yet but its on the list to do along with new headers.