from a dead stop im getting popping from the carb and sometimes the engine shuts off????? do i need to lean out the mixture or is it not getting enough??? i have a holly 600 with a holly street dominator on a 305 lg4

 

Popping back out of the carb is almost always a lean problem. You may have an accelerator pump issue, or a power valve issue (number too low).

 

Could also be a timing issue.

 

i know my timing is not perfect, didnt know it would effect it that much. getting it dynoed and tuned early next week, after i install exhaust. i know nothing about timing right now i have the mixture at about 1/3 of a turn out, is this too much?

 

alright set the timing.....the popping is gone but there is hesitation when i press the gas im moving foward though.

 

Check the vacuum and get a new powervalve... I had the same problem... turns out the stock 6.5 that the holley i bought came with was far to small for the engine. (I guess it is supposed to be something like half your vacuum at idle i think, and My 305 is pulling 20" so then supposedly i will need a 10 or 10.5 i think...)

Anyone else know for sure.. Nice to narrow a problem all the way down.. but always nice to make darn sure you have everything straight before you tear into a carb to replace something lol

N/M my question i figured it out... was forgetting a step in there.

 

i have no idea how to check the vacuum......anyone help me out? sorry im a noob to this

 

checking the vacuum on the motor is easy. go to your local parts store.. buy a vacuum guage (around $12) hook it up to a manifold vacuum source. And it will tell you. it is probably one of the best things you can have for tuning the carb i think.. since it is alot more sensitve to changes than the tachs in our cars (which lets face it by now are old and tired and I doubt they are the most accurate things in the world..)

 

thanks for the info bro.

 

Oh yes.. the vac guage is also a good start for tuning the carb as well as detecting other sources of problems (like a bad valve / rings and such).. just depends on what that needle does when the car is running and it is hooked up.. When you go to tune the carb however. you should put it in Drive if it is an AT and then adjust the screws. also putting it in drive and taking a reading should give you an idea of which PV you will need. the 6.5 is supposed to do everything above 12" of vac. if you are 12" and below then you take the reading and divide it in half to get the proper valve.