Backfiring through carb under hard acceleration! ???
 

What cause this. I am kinda learning on a trial and error basis here. I just rebuilt my carb and got it running halfway decent again. This car does not deserve to run decent. It should run like a bat out of hell! What causes this? Lean? Rich? I dont know.

It is a 750 dp mech secondary with a proform main body and quik fuel throttle plate


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86 gt, 359w, PA reverse manual c4 with 3800 JW convertor, stock fully ported studded heads with pioneer springs, manley 1.94 1.60 valves, trick flow stage 1 cam, pushrods, and HS 1.7 rockers. Bottom end was balanced and assembaled with clevite H series bearings and ARP studs, KB pistons. Victor jr. intake, proform 750 dp, and a lot more.

Backfire throught the carb is a lean condition. Make sure all your holes line up for accel pumps. Maybe a gasket not lining up or something like that. Without engine running open up the throttle and watch the action of accel pumps (did you change the cams on the throttle linkage?) Then look down the venturis and watch the spray coming out of the nozelles. Make sure pump arms are adjusted right.

How do I adjust the pump arms?

Everyone has their way of doing it but I like to adjust the spring loaded bolt as tight as it can get and just touch the pump arm. This way you get good action and still have some play left at full throttle.