Guys i will be the first to admit that i need help on this. Do i really want a 5sp? the reason i ask is that i can find alot of 4sp toploaders for alot less money. I want to do this change, but I do not want to spend a small furtune! please help
1. Do you want to drive on the interstate? I believe our illustrious leaders in Indy are even now considering raising the speed limit from 65 to 70, meaning traffic will flow between 75 and 77 in most spots.
If your answer is "No. I'm just going to keep it in town and on the slower 2 lanes." Then you really wouldn't benefit from overdrive.
2. Are you OK with running a very high (low numerically) rear axle ratio? If you're OK with running a 2.79 ring and pinion, you won't really need a 5 speed either.
The only way you can really screw up here is to do something that you don't like when you're done. If you think a 5 speed is the way to go...then wait until money isn't so tight to take on the job. There's no sense putting in a 4 speed and then wishing you had gone a few hundred more for what you really wanted.
You are right. I rarely drive mine on the interstate (over 55) so it's not an issue for me. When someone is in the car with me & we're running like 50-55 they say it needs to change another gear. We're all use to the overdrives in the cars now, so we're not use to the sound of the engine turning 2500 rpm's @ 55 or so. But I DO Love the sound. ::
I have 3.25 gears in mine & they are enough to get me off the line & still be able to drive on our local by-pass around 55-60mph.
Gas milage is another point. I haven't checked mine, but I doubt it's very good. I don't care though. But if it's gonna be driven a lot about 55 then it would be an issue.
Even the 4 speed swap is gonna cost over $1000. I did all the work myself & I still put over that into it. Of course the 4 speed & shifter were $400 each.
What do you have now? C4? You might be hapier with a good AOD instead - - no hassle changing pedals or installing clutch linkage.
If you really want a manual there is another post this morning about a world class T5 for $900. Add another $100 for a "real" shifter, $50 for a used late model bellhouse and you should be at the same point as a toploader.
I have a T5 in the '67 with a Pro 5.0 shifter and a hydraulic clutch. Great setup, love shifting, cruises well at 70 with 3.55 gears, but if I had to do it again I might think about a built AOD (my knees are getting old.)
I love the T-5 in my '70 Mach 1. I have a 3.00 rear-end but the 3.35 first gear is a rear stump puller getting out of the hole and second gear is great for laying about 6 feet of rubber too. With the 351C-4V I still only get about 12 mpg around town but 25 mpg+ on the road, which is a lot better than the 11 to 16 it got stock with auto. If you're going to spend the money to convert, then for a little more cost but less wear on the motor and better mpg, go with a 5-speed. This had got to be one of the best retro-mods going.
Once you drive a classic with an Over Drive, there's no going back. I have an AOD in my '66, and Tremec TKO-600 in my '69. When I drive either of my kids' '69's with C4's in them, I want it to shift one more time and drop those RPMs down and neither of them have steep gears in the back.