Gas Research twin throttle.
440 primary, 400 secondary, twin B2's, twin AMR lock offs, 3/8 copper line then splits to two flex lines before the lock offs. McMillan tank. Self installed.

Might play a little with the tb's. The 440 is from a single carb kit i bought new for another 351 so is jetted correctly, the 400 has seen duty on a few of my 6 cyl set ups and would likely need the metering rod looked at. I'd be certain its running rich as it is.

Also considered using the smaller carb as the primary....easy enough to swap and swap back. I sourced an APA tank and want to re-do flex lines all the way from the tank to the convertors. Might take it in to get this done and dyno'd and complianced all at the same time.....cha ching rebate

btw there is no such thing as economy with a 3500 stall

The point at which max advance is in, is irrelevent. Vac advance gives an offset on the mechanical advance curve that gives more or less advance depending on vaccum. Therefore it is spark based on load not just rpm. Spark based on just rpm is flawed.
Ideally you would have a fully mapped ignition computer but, in the absence of that you have vacuum advance.

Pete.

I realise how vacuum works, but the setup this guy is running it will always be at max advance either way.

If its always at max advance there something wrong with it. It has to go from idle to a higher rpm at some stage and you can't tell me it will never be driven at any load other flat out?