Ok. I brought something up like this a month or two ago but now the problem is very bad and has many more symptoms.

My 350 will idle ok but I start to give it gas (feather foot or lead foot) and it starts to sputter trys to run and then dies. Some times though I nail it and theres a cloud of tire smoke and away I go. Also when it starts to run better and I start to put a load on it it will get a surging and won't pull any more. If you watch the tac it will jump and fall 1000RPM and will continue even after I let off the gas for a second or two or back fire through the carb. My understading of backfiring through the carb leans to valves out of adjustment which I have checked or timing. The carb is at the moment a 750 Carter I have had 2 other 625's on it with no change, with and electric 100gph 5-7psi pump. The ingition is a stock HEI with an accel modual (it did this with the stock modual too) with accel cap, rotor and super coil. Personally I think by the way it acts off idle the time is off but its showing 12initial. My dad is insistant that the carb is flooding it but it didn't run even with the carb set up for my baby 302. And I have had jetting and mettering rods from one end of the spectrum to the other. What do all yah think this could be? I was going to by a MSD 6AL igniton box sometime but now am considering buying a distributor too.

------------------
JT
71 SS Vortec 355
www.angelfire.com/co/KellyMotorsports (http://www.angelfire.com/co/KellyMotorsports)



[This message has been edited by L6571SS (edited 09-01-99).]

When was the last time you changed your fuel filter? Also, could there possibly be something in your gas tank? I know growing up a favorite trick of the local hooligans was to drop a ping-pong ball into the gas tank. Could only do this with the old leaded cars with the wide filler tube opening. But then that wouldn't explaing the backfiring. Be sure you are at the correct TDC. For help with this check Wes' Tech Reference section. It's in the one for HEI's. Here's the link:
http://www.chevelles.com/techref/ftecref5.html


------------------
Fred (Southern NJ)
Madness takes it's toll, please have exact change.
'70 Chevelle
www.geocities.com/motorcity/shop/9385/1970Chevelle.html (http://www.geocities.com/motorcity/shop/9385/1970Chevelle.html)

Had the same problem, took two weeks and alot of "F" words to figure it out, but then again thats how all problems are solved!
1. fuel pump and filter must be below sump and/or pickup and as close as you can get them to that outlet, if not you will pump air sometimes, causing a lean condition which will cause a backfire.
2. Tank must be spotless, no rust, dirt,etc. if not particles will get into line and into regulator and destroy it or cause sporactic flow.
3.check regulator for consistant pressure, like watch it for 5 minutes, see if it stays steady, they WILL goe bad.
4. check venting, very important!
5. If more than one carb, make sure each carb has it's own regulator, a must.
6. Make sure you use the best spark plug for your car, see what edelbrock recommends.

all these are from one experience that drove me nut's, promblem was solve with a fuel cell and pump located properly, along with anew regulator, etc.

------------------

Chances are its not the fuel filters as in I changed those about two weeks ago. And I doubt theres a pingpong ball in there cause it started right after winter and the car didn't spend more than 20 minutes out all winter and those 20 minutes I was driving it. But I will try hanging the pump a little lower if I can to see what happens.

------------------
JT
71 SS Vortec 355
www.angelfire.com/co/KellyMotorsports (http://www.angelfire.com/co/KellyMotorsports)