hi i have a 302 HO bored .30 over, forged pistons and rods, e7 heads, edelbrock rollin thunder cam, longtube headers, weiland street warrior intake, holley street avenger 670 carb with 5.5 power valve, pro form hei dist. with an accel weight and spring kit, on a t5 trans with stock rear end gearing. i just got it running again after i blew a head gasket. i drove it and it runs great until you put the throttle down all the way. it hesitates big time. partial throttle no problem, but once you mesh it down it'll bog or hesitate. i believe i need to increase the shooter size on the carb considering it'll backfire out the carb under no load when i put it down. but i think there might be a little more to it. other than this problem it runs and drives great. has loads of torque and it just keeps going under partial throttle. but whats fun about partial throttle? any suggestions would be awesome. I've always had great luck on this site, you guys are great! thanks in advance!
sounds like a problem with the secondaries. either they are not opening or no fuel is flowing or something is messing with the transition. you say it hesitates or bogs, does it clear up and go after a moment or does it just bog and not go till you let off?
it won't go until i let off. i have the lightest spring in it right now. i got a 35 shooter for it so i guess ill see if that helps...
Yeah sounds like you probably have too little fuel when secondaries open... From your info about the only possibilities there are a very low float setting or maybe the fuel passages from jets to boosters are plugged up... As far as pump shot all it does is start the venturi action in the primaries, so unless you are talking double pumper, has zero to do with secondaries...
i would be looking at the fuel supply in the secondaries. most likely its the float level is too low or even keep the needle and set closed, or the needle and seat could be plugged up, or the jets or passages in the carb are plugged up.
Okay I'll look into that. Ran outa time today(gotta watch Sunday Night Football lol) so I'll look at it tomorrow
That's probably the issue right there since that carb won't sustain a long enough pump shot from the primary shooter to cover up the hole created from too early a secondary opening. That's getting overzealous for that little motor anyways(you could close the secondaries completely.. jet up the primaries.. and notice very little actual top end power loss(maybe 20 horse at the most).. and getting into double pumper territory.
Absolutely. Also, what better way to tune the primaries.. (accelerator pump shot included(volume and duration).. than by eliminating the secondaries from the equation? Basically it's like this. You use the process of elimination to pinpoint the circuit issues you're having here. No secondaries?.. no transitional bog. If the problem goes away after doing that?.. then you know where the issue lies.
could it be an advance curve issue? i put in the black spring (heaviest) and it helped a lot but it still stutters a bit when you step on it. but the thing I'm confused about is that it diddnt do that before the head gasket. the only other thing i did was add the accel curve kit to my distributor... thats why i ask about the advance curve
My suggestion is take out the accel kit and give it a go. If it fixes at least you know for sure that's the problem. Sounds like that's your issue.
