Howdy, I have a 428 Fe that has a mild cam 6al box, pro billet distributor, edelbrock carb. intake and cam. First I had a 800 cfm edelbrock carb on it and when I got on the gas real hard the engine would spit and sputter and sometimes almost cut off until i let of the throttle. It ran real rich so I decided to switch to my 600 cfm edelbrock, same thing happened. I had this guy help me to build this motor and when I told him what was goin on he said the spring in the cap needed to be changed, so he changed it and it helped alot. Well now when it idels its fine or when ur just cruisin it does alright. But when u try to get on the gas it backfires through the carb the truck hesitates and then takes off. This is when its could(worse), hot moving or from take off. I cant figure out whats goin on. Any suggestons are needed. Also I have checked timing and vaccum leaks.

 

Checked the timing, huh? Do you know what the advance curve is in the dist. What is the total machanical advance and at what rpm is iy all in at? What is initial timing? Sounds more like a timing issue than a carb issue or possibly a weak ignition system.

 

Thats how a bad timing chain acts. Could you have installed your's a tooth off?

 

well I wouldnt think that the timing chain was a tooth off, but as far as the ignition setup its a Summit Package It includes the box, dist, and coil u can find it at Summit Racing - High Performance Car and Truck Parts | 800-230-3030. Part # is Summit SUM-850073

 

May need to make some changes to accelerator pump, 30cc-50cc, squirt nozzels, and/or ramp.

If the dist is mechanical only, you may be flooding it. Normally if lean it will back fire through the carb. When you set the timing are you in the 10 deg range. With mechanical dist you set it as high as you can.

Good luck

 

Yeah,I had the same problem.Had no light so I had a garage set the timing,also put new distributor in.They set timing at factory specs-6 degrees.Bacfired through carb same way.Recently set timing to 11 deg. , now runs like a CHAMP

 

Unless you have a race motor with a mechanical secondaries, no one needs a 50cc pump. They are not for street engines.

 

Thanks gearhed1971 I beleive that might be it. It just may be set to stock degrees and actually needs to be higher. If so it would still read in time either way right, even the way it is now. Ive also been told to look at the stream that comes out of the squirt nozzles in the carb to see if i get a steady stream and a immediate response when I hit the gas. Question though, How do I change the degrees can I rotate the dist. or do I have to turn the gear alignment on the timing chain. thanx lots

 

Do you have a points distributor,or electronic?

 

the part num. is SUM-850073 its from summit. it has a ignition box and is mechanical advance.

 

Sorry,have only dealt with the stock points setup.Don't know about tuning them

 

Yes,I assume you can just rotate your dist.Check your instructions at the bottom of the summit part# page-sum-850051.pdf 210 KB

 

thats what im thinking is that I can rotate the distributor opposite the rotation and it will advance my timing. Thanks for the help.

 

Guys, the timing advance and retard stuff is way to basic to be confused about. Don't be changing your timing without a timing light or you can end up with not only a poor running motor but a broken one.

 

yeah,definately use a light,always good to know.