CarbDoes it back fire thru the (yuk!gasp!) carb or the exhaust?
CarbDoes it back fire thru the (yuk!gasp!) carb or the exhaust?
Was the problem there before replacing "the plugs and everything"? If not, I'd take a closer look at the new stuff.
I can't help that much help on carbs, but since we're doing things the old-fashioned way, I'd read the plugs. Shut off the car at WOT at the RPM you've gotten backfires and pull the plugs. Figure out if the fuel is right. If not, adjust your carb/jet as necessary. Just based on what I've read over the years, a 650 DP seems like a big carb on a 302, but this is really not my area.
If the fuel is fine, you could should start looking to the ignition system. While you pull the plugs, check the gap. I think stock gap was in the .050-.055" range. If you have a weak ignition system, you might be able to compensate by closing the gap to the .030 range. MSD boxes fire multiple sparks and can help clean up some misses. What coil are you running? How does your motor manage timing advance? What is total timing?
Like a lean pop, hmm?
Does it back fire thru the (yuk!gasp!) carb or the exhaust?
Was the problem there before replacing "the plugs and everything"? If not, I'd take a closer look at the new stuff.
I can't help that much help on carbs, but since we're doing things the old-fashioned way, I'd read the plugs. Shut off the car at WOT at the RPM you've gotten backfires and pull the plugs. Figure out if the fuel is right. If not, adjust your carb/jet as necessary. Just based on what I've read over the years, a 650 DP seems like a big carb on a 302, but this is really not my area.
If the fuel is fine, you could should start looking to the ignition system. While you pull the plugs, check the gap. I think stock gap was in the .050-.055" range. If you have a weak ignition system, you might be able to compensate by closing the gap to the .030 range. MSD boxes fire multiple sparks and can help clean up some misses. What coil are you running? How does your motor manage timing advance? What is total timing?
The mixture screws at the base of the carburetor only affect the idle and off idle mixture. You have to dig a lot deeper to find the main mixture metering system.The part that doesn't make any sense is the build is fresh less than 6 months old heads checked no warpage no broken springs bc I checked them I pulled valve cover off there's no dead lifter or excessive play in the valve train from the intake up is all new less than 6 months including arp head bolts this recent backfiring started randomly one day it passed inspection and everything months ago no vacuum leaks on any hoses at all need to pull the plugs and take a look I have a 200$ fuel pressure regulator from jegs I have stock fuel pump and stock fuel filter that I didn't change I richened it with mixture screws that didn't help aggravating tbh does not do any backfiring or missing during low speed or idiling
Yea, power valves, squirters, main jets, float level, it's all part of the myth that a carb is easier than efi.The mixture screws at the base of the carburetor only affect the idle and off idle mixture. You have to dig a lot deeper to find the main mixture metering system.
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