c-6 trans swap

[alphawave7]

My 390 with rv cam , 670 Holley, Sanderson headers, c6 and 3:55 gets about 8 mpg.

I bought it to drive a good bit, but the gas mpg is killing me !

Wow. My 390. 650 Holley, stock exhaust, C6/3.55 gets 14+ MPG's..but only when freshly tuned and full tire pressure.

[JTW_Jr]

Perhaps my right foot is a tad heavier than I thought.

[alphawave7]

Perhaps my right foot is a tad heavier than I thought.

Or you're stuck at stoplights! I just ignore those. I put two new 9.50x16.5 Firestone Transformer HX tires on today (about $350), replacing..get this...20 year old Kirkland, yes, Costco 16.5 tires. I wanted to load some rock, about a cubic yard, in the bed, but was NOT gonna happen on 20 year old rubber! Costco just laughed at me when I asked about 16.5 tires, as did everyone else. Firestone actually hung up on me after saying 'Special Order', and no other offer to assist, but in the end, Big-O Tires was able to get them in overnight, and cranked them on for $20 a pop.

[JTW_Jr]

Stop lights and stop signs are just an excuse to accelerate

After all STOP does stand for Spin Tire On Pavement

[BobB]

i bought the truck new with 302 3 speed it only got 14 mpg in 1972 now 42 years later with the same 302 but
with a c-6 and 355 gear about 10 or 11 i changed the gear to 300 hope to improve milage if not would try
different carb it has aftermarket 2 barrel now i am open for carb options ?
thanks
BobB

[alphawave7]

i bought the truck new with 302 3 speed it only got 14 mpg in 1972 now 42 years later with the same 302 but
with a c-6 and 355 gear about 10 or 11 i changed the gear to 300 hope to improve milage if not would try
different carb it has aftermarket 2 barrel now i am open for carb options ?
thanks
BobB

I'm running the 2100 Motorcraft and getting (decent for an old truck) about 12-1/2 mpg at last fill up. New tires, full of air. I can eek out another mpg or two after an oil change and full tune-up.

[bumpandsweptline]

Are you still running point's ? If so a dura spark upgrade is supposed to get more mpg .

[BobB]

I do not have points any longer I swaped them years ago after the rear end change still getting 10 mpg
I guess try some carb work don't know what
Bob B

[Craigerf100]

Are you still running point's ? If so a dura spark upgrade is supposed to get more mpg .

Good call
dura spark is good. I dont know about mpg but when i switched to an electric distributor. It made a world of a difference.