I've got a 402 in a 65 chevelle. I just got it running last week. Now i am wanting to get my carb dialed in right. I'm wondering about the jetting. whats the best way to set it. Anyone have to lower the jets on theirs. My combo consists of:
402 block
lunati 225/235 @50 .540/.550 lift
215 heads mild port work, big valves
edelbrock performer rpm intake
headers
1" carb spacer
holley 870 street avenger
3" exhaust to 2 40 series flowmasters dumping in front of the axle

I've been getting some popping at rpms around 4000. but i think my timing may be off a little.
thanks
josh
65 Malibu

Check your timing first!

the last time i took my car out for a ride i forgot the distributor clamp was loose. the distributor ended up turning and the timing ended up severely retarded :D

the 427 didnt like that at all, it was spitting and popping around 4500. that drove me crazy and i thought it was carb related, i messed with the carb until my face was blue but no luck. then i pulled out the timing light and checked timing, and what do you know it was way off. so i set timing back to spec and it ran great again.

i have ran into a few times that to much timming will cause popping in the higher rpms......but that is with a hei unit were some of them have to much mech. advance built into them......so i would weld shut the "slots" to close the gap us so my bbc's run with about 20* initial and 36* total at around 3000 rpms........but if your running an older style points set up then points bounce is common.......

in any case the timming should be sorted out first then move on to the carb to get it dialed in.........

i have jetted down carbs for the winter time since the air is alot more dense and richen them back up for race season........when its hotter out.........the way i set my jets are thru test and tune at the race track. i start with the factory rating and go from there..if there has been some mods to the carb like most of mine do see then thru an educated guess is where i start and take some trial runs down the road and pull a plug to see what it looks like and go from there...........then test and tune at the track get me closer by watching mph since that is the sign of hp your making..........