Best low end torque from a 350 V8 I had in my '72 K5 was when I put a Rochester 2GC 2 barrel carb and intake off of a 283 on it,that had 1-1/4" throttle plates...when I had that combo in it I could lug it down in third gear and accelerate smoothly and no pinging or bucking...
After I got a free stock cast iron 4 bbl quadrajet intake and carb from a friend,I decided to swap that on it...immediately it lost a good deal of its low end torque,and bucked and pinged if I lugged it at all,and gas mileage went from 15-18 mpg to 12-15 tops,worse in colder weather...I wished I hadn't sold the 2 bbl setup!..
One carb I have a few of,is a Holley 2 bbl "Economaster" designed for the older GM's with the small barrels,they also fit on an older 318 Mopar..I got 18+ mpg with one on my 307 in the G-10 van I have,and it ran much better than the rochester,which had accelerator pump troubles,had an annoying flat spot and hesitation I just couldn't get rid of...found both of the Holleys at swap meets--paid 3 bucks for the one on my van,the other I had to spend twen bucks to get it..
I had very good performance from a Holley Economaster (model 4360) I put on my 454 in a 74 C-10 also...leaner IS eaner,it gained about 50 HP over the flooding Q-jet I replaced with it,and gas mileage improved considerably too..
One Rochester carb I liked was the old 4GC ones used back in the 60's...had a few of those and they all ran strong...
