GEAR VENDOR PRO's AND CONS

[bb71challenger]

I agree. With an 8 3/4 rear end its too easy to swap gears. I have a 2.94, a 3.23, a 3.55 open thats hurt, and a 5.13. I love the 2.94 for cruising but would like to try 3.55 or 3.91 sure grip just to see what its like.

[71chally416]

Something being missed in this conversation is it will futher emasulate a little 318. It's another  thing to OD a big block that can cope with the low RPM and added mass and weight.

A better plan would be to buy a used car that gets great mileage for less than what the OD would cost you and use that when you have to drive a long distance at highway speeds. I have no regrets paying $850 for my Iroc Daytona 5 years ago. It still runs great.

[TRIPLE-GREEN]

That has been what I have been trying to do for the last month. But no one has anything I would put money on. So I wanted to try to make the car more eco. so that it would not be so hard to take it across town or to a show. Looks like that is a little tuffer then I thought.
   I love the car and feed it with not much remorce, but it would be nice to save a few bucks here in there to justify using it so much. Right now I am getting about 125-140 miles Freeway out of a tank. Does that sound right to you?

Good clean runing 318, stock 4 brl intake with 600 Edl. carb (New). Will convert to duel exhaust in coming weeks. Stock ign (electronic) Also I am pretty light on the peddle. Let me know if you think that is about right or something is a miss.
 

[MJS73]

For me, it's not about the 2 mpg increase, it's about being able to run a 3.55 around town while cutting the revs and wear on the engine on the highway. I have better things to do than to swap rear end gears because I plan to hit the highway and it makes no sense to buy another car and not drive the Challenger that I don't get to drive often enough. If you want to enjoy your car in any situation without additional work, the GV unit is a good choice.

Mike

[HP2]

Biggest bang for the buck in power and mileage increase you can make is to increase compression ratio.  This can be done be a)putting higher comrpession pistons in it b) putting smaller chamber heads on it or c) putting a shorter duration cam in. Increases in dynamic compression make more power and torque across a broader rpm band, which can allow your engine to operate more efficiently across the range. More efficeint operation uses less fuel to make power which achieves better mielage. However, since your engine is intact and running, these aren't necessarily easy things to do.

I agree with CP that simply dropping your cruising rpm may not yeild an improvement and could actually make things worse if you are out of your power band and applying more throttle angle to keep things moving.

[TRIPLE-GREEN]

 

[dodge freak 2]

People had no problems running 4.10 gear cars on the freeways in the early 1970's, some screamed-cried when that drive 55 mph came around.

I see 4000 rpms in my 3.91 car at a steady cruising speeds, like wow that does seem a bit high but with my "quiet" exhaust and loud stereo it really doesn't seem to matter, its the motor running that speed-not my legs. Motor seems happy, gasoline isn't too expensive. Passing other cars is a breeze....150 mph it can't go, not even close but it can go easily over triple digits and faster than I see most anybody else going.

55 mph is at 3000 rpms, feels just about right there but is too slow to keep up with traffic so I just grin and bear it, crank the tunes up and enjoy life. Engine keeps working, trans keeps on shifting (not on the freeway, just stays in 3rd gear) burns the gasoline up but the gas stations always have more to sell me (unlike in 1973)