carbed 308 Backfire?

These sorts of problems have plagued my 308 right from the beginning. I know how to adjusted webers. My 914-6 & my Urraco all run great. That dam 308 is the one I can never get right. I have had it close before.

Backfire on Decel is the current problem, I can make that go away and it wants to backfire while idling. AKA it will run way to rich or way to lean and once it is set it changes. Yes all the balance is correct. I must have variable vacum or exhaust leak.

I almost give up. It is such a good looking, nice driving car.

 

before I had my carbs adjusted and the leaks addressed, the car would backfire pretty much anytime it was idleing on shut done above say 1200 rpm. The 100% effective solution is to reduce the idle to below 1000 before you shut down the engine. never had a backfire in that condition.
the problem was the carbs and idle was not set correctly (don't ask who fooled around with it) either it was too high or too low. at too high it would backfire on shotdown, too lowl it used to stall out.

haven't tried shutting down above 1200 rpm. I'll try it and report back.
if it doesn't, then maybe it's the air leak thing per previous posts, if it does, the I guess it's just it running or idling too high for shutdown and leaves fuel in the system.

re the clutch fix. can't image engaging the clutch slightly and tiny amount of braking can hurt a clutch if it's in otherwise good shape.