the edelbrock #1407 750 only requires a pri metering rod and or pri jet swap to improve the fuel mileage.
Its factory calibrated a bit rich for power.
lean it down on the primary cruise. The secondary jetting is fine and does not effect mileage.
Its not too big and its very tunable.
You don;t need a new carb. Just tune the 750.
A AFR gauge will help you dial in the jetting.
A cheaper narrow band type (with heated 02sensor) is good enough for this.
Its a real eye opener.
The 230° cam has to go if you want mileage.
The duration and LSA(overlap) is too high for mileage.
A cam with 208 to 214° @.050" intake duration and a wider 112+ LSA will help a lot. A single or a dual pattern cam is fine.
it will still go like hell.
I've used the 214-224 .442 .465 112 cam with good results.
* summit, crane blue racer etc*
Recurve the distributer mechanical and vacuum advance curves.
They both need optimizing.
The 230 cam will need lots of initial base timing at idle 24-26deg at idle
vacuum advance also needs to be dialed in.
The stock-default distributor curve will be all wrong.
The jetting and distributor curves make a huge difference.
The high stall converter is not as bad as you think as long as you can keep your foot out of it.
If you are heavy on the foot you are going to burn gas.
How you drive has more to do with it.
I used a 214-224 cam and a 3500stall converter and 4.10's and it was reasonably good on gas. Again, if you rug it a lot, you are going to use fuel.
get the jetting and timing curve sorted out and see where you are at.
then find a milder cam.
This is what your 230° cam needs:
start with 24-26deg initial 10-12deg mechanical (34-36 total advance)
shorten limit the mechanical advance travel limit stop.
+ 10-12deg vacuum advance that comes in at hiway cruise.
Ported or full manifold vacuum source no rules, don't care, use what works.
swap the primary jet to a .110" pri metering rod .075"x.047"
4" power piston springs yellow
This will lean down the part throttle cruise and insure the power piston stays down-lean at idle.
This and the ignition recurve will really clean up the idle and low speed and mileage. Get new plugs with the correct heat range.
A smaller voodoo cam will help #60100 or 60101
Lunati #301A2LUN or 301A4LUN are other good choices.
Anything mild like this is good.