JJokr990

well i've got a 383 that i recently bolted on a high rise intake manifold and 600cc carb, now there's backfiring coming out the top of the carb. my first thought was timing, i've gone through from 0 degrees to 25 degrees retarded and everything inbetween and that did'nt really do much. next i thought it was the carb itself, so i've adjusted the floats all over but i know it's supposed to be somewhere around 1 1/4 turn screwed out, give or take a few tweeks. that helped a little but it still does it if i either mash the gas or totally let it off in high rpms. i was told that i may have a floating valve so i took one og the valve covers off to see if the springs were worn but they seemed fine, i couldn't move them by hand. the only thing i could think of is that the heads need to be toally readjusted because of when my timing WAS off it was backfiring all over the place. so i'm thinking that could have thrown off the timing of the heads. i'm a little stuck on what the problem could be, any advice or suggestions?

64polara

did it do this before the high rise and the carb?

JJokr990

yea, it did with just the carb as well. you think the carb is the problem?

rexus31

Are you sure the distributor is in the proper orientation? It sounds like you are 180* off.

JJokr990

i think im i've got it right but i'll try flipping it and see what happens

67 GTX

i agree with you here
doesnt sound like it is the carbs fault

Polaradude

Perhaps a vacuum leak ?

theomahamoparguy

what kind of 600 is it? Holley double pumpers are notorious for having too much of a rich idle. Usually the vacuum secondary holley's are ok. Must make sure you got the right base gasket for the carb. ALSO; where do you have your vacuum advance hooked up to? Try unhooking it and plugging the hose to tune the idle. Just some thoughts to try.

JJokr990

apparently i tuned the carb wrong, i wasn't supposed to tune it with the vacuum advance hooked up. so i did that and adjusted the distributor a bit and now its running better. its an edelbrock. now i think there's a spark issue cause it's running like all the cylinders are'nt firing. my guess is the wires/plugs. what do you think about switching to an HID disrtibutor?

theomahamoparguy

my guess is you need to go over all the basics. Plug gap, dwell, timing. Yes it could be wires and/or plugs. Electronis ignition would be a good idea. If you have a points type dizzy, the dwell must be right or the car will run bad. USE A DWELL METER TO SET POINTS! also, check the firing order. Hving 2 wires crossed will make it run bad also. timing should be about 10 btdc at idle. {700 rpm?-just a guess}

JJokr990

i was using a feeler gauge to set the points at .016mm, that may be the problem. i'll try the dwell meter and if it's still bad then i'll check the compression in the cylinders.
two other questions: 1. if there's radiator fluid spillin out the top of the radiator (i have no resevoir hooked up) would that be a bad thermistat or is that normal? 2. how would you replace the box on the steering column for the power steering? i've got fluid leaking out and the pump is rebuilt and i don't see any holes in the piping