Switch from a th350/203 to a 700/241

[Cornfield creations]

I know this has prob. been covered before but I couldn't find it.

My 79 has a 350/350/203, with 4:10 gears and 35's my around town gearing is great. Highway I am taching pretty high, and I believe I could squeeze some better MPG with an overdrive and lighter transfer. I am getting about 11 mpg on the highway if I am easy on it. But at 55 I am doing 2500 rpm.

With a lockup 700/241 I could easily drop the rpm's by 1,000, maybe more.

I am just curious if this swap would be worth it though, cost wise. Nothing wrong my my trans/transfer, just wanting to upgrade...

 

[sweetk30]

http://coloradok5.com/forums/showthread.php?t=269893

th350/203=2703 rpm @65 mph

700r4/241=1791 rpm @65 mph

dont forget requires tcase shifter/driveshafts/possible crossmember dep on adaptor used/tv cable and bracket/lockup control kit/241 with mech speedo guts/few other ods n ends.

lots here have said 35" tires and 700r4 on highway require deep gears of the 3-4 hunt will happen and lockup convortor will cycle in/out a lot. 4.10 not the best for the 35" tires. thay tend to run bare min 4.56 but 4.88-5.13 best.

 

[Cornfield creations]

gotcha. I Remember reading that about the 4:10's and 4:56's. Is there a torque converter lock up kit for the th350?

 

[sweetk30]

if the th350 is a th350c model . but i think those were in the 80's only.

 

[Cornfield creations]

ok, thanks guys!