ok, so i just finished a new motor. 302, 10:1 compression, Lunati bracket master hydraulic cam, AFR 185 heads, msd pro billet, speed demon carb, shorty headers. on start up motor seems to have trouble staying running for the first five minutes before it will idle without me goosing the pedal. This could be normal, ...what isnt normal to me is how when the thermostat has opened (180) and i leave the house with the car it accelerates (slow acceleration)to about 2500 rpm and then begins to pop out of the tailpipes for three to four miles regardless of gear (manual) and then stops, runs fine all through powerband after that. Is it possible that the exhaust pipes are trying to warm up? i would think once the car is at operating temp..its at operating temp..any insight? carb issue?

 

Sounds like a choke problem to me.

 

Would be the first thing I'd check as well. Make sure the top butterfly in front is fully open when warm before you go on the drive. Is it manual or auto choke? Does the problem disappear later in the drive?

 

i wish it was that easy....my carb in question is a spped demon 650 with mechanical secondaries and choke delete.. no linkages no upper butterflies no nothing. and yes...the popping noise does dissapear after five minutes of easy cruising... runs great after that..