I have a 1964 F350 with a 292 engine, The carb has been set up, the plugs and wires are all new, and headers and new exhaust system was just installed. I have noticed that when the I decelerate by downshifting, braking or take my foot of the gas going down I get a popping sound coming from the exhaust. Last summer I noticed the same thing, I took it to the mechanic and he said it was normal, then I got on the highway and bang a muffler split, that's why the exhaust system has been replaced. I figures it was caused as the exhaust manifold had no gasket and were leaking, I am surprised that with a new exhaust system I am still hearing a popping sound. I had the shop that installed the exhaust have a listen and they too said it was normal.

I am thinking it may be timing, but not sure. The only other symptom is when I tramp down on the pedal she stumbles before it takes off.

I have never had to advance or retard the timing, I found a write up that makes it seem fairly simple, that being said any advise or guidance will be appreciated. I do not have a timing light, vacuum gauge, or any special tool for timing.

Thanks

 

Sounds like a crossed plug wire. Make sure they are correct.

 

All wires are correct. Just double checked tonight.

 

The back firing and blown muffler is the product of raw fuel in the exhaust igniting. So somewhere someway that fuel is not being ignited in the cylinder and just being passed off. I still say something is wrong with the firing order.

 

Pull a couple plugs and see if they are sooty black. Carb might be too rich, that could cause the decel backfiring as well.

 

You are experiencing classic symptoms of the distributor advance mechanisms not working properly. When you decelerate you have a very lean mixture. In order to keep the fire lit and not put raw fuel in the exhaust it takes a lot of advance 30 degrees +. If your mechanic has a dial back timing light and a hand held vacuum pump he can trouble shoot your distributor in 10 minutes. But don't take it to the one who told you that popping out the exhaust was normal.
I don't have the specific specs for your truck but these are for a 292 and should be in the ballpark.
This is crankshaft degrees.
Centrifugal advance start, 4 degrees @ 1600 rpm, max. 24 degrees @ 4000rpm
Vacuum advance, start @ 7 inches of vacuum, max. 24 degrees @ 20 inches.

 

I think the timing marks may be gone on, I cant find a pointer. Anyone have a pic of what I'm looking for. They were easy to find on my 68 Mustang but I can not see anything on the 292 Y block.

 

You can sand the balancer, that should reveal them. Try 100 grit.

 

I planed on trying a wire brush or sand paper on the balancer when I get a few minutes, however there doesn't seem to be a pointer anywhere I can see.

 

Pulley should have a notch in it for TDC. You can also just try turning your distributor a little each way youself until you notice an improvement. Just loosen the one bolt holding the distributor down to the engine block.

 

I found the notch but not pointer

Think I'm gonna try what you said advancing and retarding slightly to see if it improves.

 

OK, here is what you are looking for. Who knows if you have the original engine, so it could be figure "A", "C", or "J". The firing order is Fig M.
If the timing pointer is missing. You need to figure out which one you need and put one on it. You don't know if your mechanical and vacuum advance is working or not. If you start cranking around on that distributor without the benefit of a timing light or even knowing where TDC is. You could end up with an engine that won't run or you could burn a hole in a piston in which case you end up with an engine that won't run.

 

The first thing you need to do is find top dead center. Use a piston stop and rotate the engine in both directions until it hits the stop. Halfway between those points is TDC. Fabricate a pointer that points to that spot. Eventually you can look for the factory pointer that corresponds to that location.

Then follow Crop Dusters directions for checking your distributor curves. If they aren't very close, you need to pull it and have it re-curved. I suspect Crop Duster is right, your distributor is not advancing properly. Moving initial timing back and forth could do serious damage. Take the time to find and fix what's wrong, don't just start making changes hoping something works.

 

Keep in mind old Studebakers had a lever inside the cab that the operator could use to advance or retard the timing. Similar to a choke, the lever connected the operator to the distributor via a cable. Your senses can go a long way to timing your engine and curing any of its aches and pains.