Looking for some advice on jet sizing- Thermoquad 6139

All,
I am looking for some input on what sizes to use in my Thermoquad rebuild that i am working on. The goal of this build was to use only parts I have laying around to get the car running decently enough to drive it as a weeekend car until I get the forever motor built. The idea is to spend as little as possible currently and do the least amount of work- with the side benefit of using parts I have laying around that aren't particularly valuable or worth selling.

Car is a 273 2 BBl 66 cuda- still original motor untouched - supposedly has 49k miles on it. Heads are shot - carb is mismatched and it has an orange box electronic ignition that seems pretty new.

I have a set of 302 heads that were freshly done when I bought them- it is intake port matched to an Eldebrock preformer spreadbore intake manifold and I have a very good condition 340 4 bbl camshaft that I will be putting in as well- Hydraulic lifters to go with the stock adjustable rocker shafts/rockers that i also had laying around.

I have a Thermoquad to use - a 6139 series 340 AT carb that I am currently rebuilding but I know that it will be jetted improperly if I put it back to stock- so the question is - what size jets would you step down to?

Please try to stick to the concept- i don't want to pull the engine - I don't want to put something else on there- I really want to use up the stuff i already own until I build the forever 340 for it.

Thanks in advance everyone,

Keith