So first let's lay out what OP Has and Wants!
Stock 72 340 eng(low compression) stock except for over bore and cam.
Quote:
My car right now has a 340 out of a 1970,that is 30 over, with a Street thumper cam, J heads with 2.02 intake and 1.94 exhaust valves, an RPM, Dual plane intake and a 600 Holley. The trans is a 727, with a B&M 2800 Stall torque and a reverse valve body. The limited slip rear has 355s.
That took over 90 post to get out of you. Sooo compression is around 8.8-9.4 depending on what piston are in there.
Now you can't have you cake and eat it too. (a GV would help! $$$$) but here i go!
Fuel economy. The mother F'ing cam (street thumper cam) is just a pretend cam and does nothing for fuel economy.(pretends to be a big cam but don't get the milage of a smaller cam that it is!) Get a cam that idles smooth as glass(talk to a cam company) get rid of the 3.55s for 2.76s and i would keep the converter, but a tighter one would help milage.
Power............ You said, you like the power you have but needs more than 6 mile to the gal
keep converter, keep gears buy a "torque cam" (Talk to cam manufacture)
And then you will need to learn how to" tune it" to get the gas milage. I say this because the combo that you have, "tuned", would get better milage then 6 mpg!!!!
