Quote:
Originally Posted by 70CHEVYBB
I have changed jets from 72 to 67 way to lean and running hot went to 68's the same and had to settle for 70's not a big difference but did help with mileage. I am at 34 degrees total timing. I have a 15 mile drive one way 10 of them are 60 mph the rest is in town but only two lights. I have thought of a cam swap but I really think I might put an edelbrock 650 on it. I really do not like the holley for everyday driving anyway.
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A 750 holley is a lot of fun but about the worst carb you can run for mileage. The reason i am perplexed is back in the day my dad had an 80 Gmc one ton welding truck. It had a stock 350 when he bought it, sm465 4 speed and 4.10 rear. He built a work bed from 3/16" steel. Hauling a lincoln sa200 welding machine, full size oxy acetylene rig and all tools it pulled down 8mpg but was gutless. After a while we swapped in a 454. Rv torque cam and headers full dual exhaust with glass packs. I forget what heads but nothing fancy oval ports, late 60's oem intake with square flange 700 carter carb. It got 10 mpg and actually had power! I still remember hearing him fire it up at 5am every day to go to work!mluckily we didnt live in town or wod have had pissed of neighbors!
On a side note, my brother wanted the intake for his 69 camaro 396 so we swapped it for an oval port edelbrock performer. Not sure if it made any difference meage wise but it definitley affected the torque of the engine vs the cast iron oem ( and not in a good way!)