wannafbody

iTrader: (1)

Just got my car running asmost of you know...

basicaly a tpi long block
headman longtubes
comp camps 279 thumper camshaft
carb intake and a 650 double pumper holley.
Stock Hei ingnition (will be changed later)
OPen headers for now untill I can afford some exhaust.


I bought the carb used and I dont belive it has the stock jets and stuff inside it anymore.
When I first put it on it seemed to idle good (much better than the Qjet)
and it was bogging a little bit but then would pick right up and scream.
I have messed with the idle some and the timming, and now it seems to idle for about 10 to 15 seconds and then slowly choke out or lean out.

Also when I pull out on the road from an idle if I floor it will imidiatly just go dead. I really have no idea were to start with jetting, any help is great. Thanks

pancherj

As I recall, the thumper cams have a pretty tight LSA. You are going to want to fisrt deal with the timing. I would be shooting for 20* initial advance and modify the HEI so it only gives you 16-18* more mechanical (you aren't trying to use a computer controlled HEI with no computer?). Make sure the vacuum advance is hooked up too (you will be close to 50* advance at idle). Get this done before you do anything with the carb...

The "dead spot" is most likely the carb going lean. You probably need to adjust the accelerator pump arms so there is very little clearance between the arm and the actuator. Eventually, you can mess with shooters and pump cams. As for jets, I would start out with 70's front and back (you do have both power valves...right?). Also, the open header-tune will be different than the full exhaust tune. If you are going to drag race with the open headers, bolt some extensions on (20" long or so).

five7kid

iTrader: (14)

Get the LIST number off the front of the choke tower, go to Holley's website to their numerical listing in the tech library, and you can see what it had from Holley.

You'll never get the carb right until you have the right distributor. Fix that NOW! Later is too late.

wannafbody

iTrader: (1)

thanks guys all help is much apreciated.
yes it has power valve in rear
What would you recomend for ignition?

What would cause it to go dead after idling for a few seconds? Im guessing its running out of fuel because When I go to restart it I have to pump the pedal a few times before it will hit again.

tkcaraudio

acelerator pump is cause of flat spot when stomping gas. You should have higher rpms before you hammer it..

Sounds like it could be loading up at idle (Dead plug running out of fuel timing wrong ect)

pancherj

I like my GM Performance HEI. It comes with limited mechanical advance (mine was 15*). This allows me to set my base at 22* so my total is 37*. It also has the melonized gear in case you run a roller cam. I don't have a module in mine, however. It runs off of the MSD box instead. I am still using the stock coil, cap and rotor that came with it.