Removal of the bridge in the manifold will make significant difference straight up. Are you running the vacuum advance off the ported vacuum port in the carb or off the manifold. On an aside, have you checked the condition and operation of the bob weights in the dizzy. Validate they are within spec.

Wot he said..

Check the timing is correct.

Then also as Benny said, check the idle to progression by disconnecting the accel pump and very slowly opening the throttle, it should just slowly increase in revs with no stumbling.

Vacuum advance is running of ported vacuum from the carb body. I'm confident distributor advance (mechanical and vacuum) is working well. I've actually slightly increased total mechanical advance (just a few degrees) by filing out distributor weights slightly. It's just the original distributor, but it's in good (however no longer original) condition.

Thanks sss. I'll do as you suggested. I've played around with this before, but only while under the bonnet. I've never driven the car with the acc. pump disengaged. I'm guessing it will suggest acc. pump not fully contributing, but will be worthwhile all the same. I'll post results when I get around to it.

So you think it's worthwhile removing the bridge in the manifold hey? I guess it can't hurt (I don't think..) and it does make sense intuitively.