setting up for circle track racing

[chevelleal]

I have a 7045250 qjet that i rebuild and put on a pure stock racecar. It just seems to make not good power. My 500 holly has more then it. I am running a 355 with 2.02 heads and cast mostly stock intake. Cam is a 240 duration, .415 lift. The qjet idled really nice with no modifing done to it, it has 67 jets in it. but just seams to be boged down on the track. it is a 1/4 high banked track. I was reading that you can take the power vavle out and the metering rods... can i also take out that third rod and that rod needle thing in the corner of the float bowl area???

[Cliff Ruggles]

You just happened to pick a poor candidate for what you are doing.  It can be made to work, but I still don't like setting up 1975 castings with the front located APT system (some also have auxilary power pistons) for racing applications running straight off the jets.....Cliff

[chevelleal]

ok. thanks i have some others one to clean up and see how they act. i will give up one that one for racing. thanks alan

[chevelleal]

Ok found another one. 17084228..with 73 jets in it. and when i take the power vavle spring and mettering rods out, do i take the spring out of the power vavle stop and turn it all the way down or just take it out??? Is this a better carb number to try on circle track?? it does not have all the other junk that the other one in it that i was trying

[Cliff Ruggles]

Nice unit, the power piston and APT is not used to run straight off the jets.  Both parts can stay in the carb, just remove the spring under the piston and leave the metering rods off of it.  Of course you need to run much smaller jets......Cliff

[chevelleal]

OK thanks.. any idea were to start with the jet size?? and what about the metering rods for secondary, any idea size on them?? Thanks for the help. Alan

[Cliff Ruggles]

Typically about 5-7 numbers smaller than what it showed up with for jetting.  Secondary metering rods will depend on many things, including the weather (DA).  We usually start out around .040-.045" and tune rich or leaner if/as needed.....Cliff

[chevelleal]

wow.. ok i will order some and see what happens. thanks much for the help! alan