Hello, I have a 1969 firebird with a 1972 455 and a M-20 trans, what is a good 5 speed to replace it with? Thanks for any help.Jay

Saving my sheckles for a perfect fit system from Keisler -

http://www.keislerauto.com/

But I'll be converting from an TH400 auto.

The TKO-500 is a real nice package, but man is it expensive. The question is what are you doing with the car? If you are going to drive it hard, the TKO may be a must because of its torque capacity. If you are going to drive normal with the occasional pounding, you may be able to get by cheaper with a standard T5. A world class T5 from an 88 or early 89 Camaro (needs to be from the 305 drivetrain) will bolt in to the stock bell housing. You will have to modify the crossmember a bit, and modify the shifter handle if you want it to come out the stock opening. Also, the driveshaft will have to be shortened. It all depends on what you are looking to do with the car. I will be swapping my TH400 to the T5 hopefully this winter. I picked the gear box up for $150. Already have the flywheel and bell, pedals and linkage. Just need to pick a clutch and get with the install once I get my car out here to my new house.

Whoa, you're recommending someone with a 455 put a T5 behind it? Chevy wouldn't even put it behind their factory 350 TPI. I've had a number of Mustang friends destroy WC T5s behind 302s.

Even without slicks and only the occasional pounding, not worth it. It might be cheaper to start with, but not if you have to keep rebuilding it. Highest torque capacity rated ever (1993 Ford Cobra) was 335 ft-lbs. I think the Chevy's were only 300ft-lbs. Even 3rd Gen Chevy with SBCs often won't recommend these transmissions to each other.

If the OP is really not so inclined on performance, then switch to a milder rear and keep the stronger (relative to a T5) M-20.

Daryl, I don't know what your engine combo is, but I hope after all this work it holds together for you. It'd be a shame to have to swap back, so I'll cross my fingers. Good luck. At least it sounds like you might not have too much money invested.

It does depend on how you will be driving it. The t-5 will take a moderate amount of hard usage. I have heard that a person can wreck one in minutes easily. I don't actually know anyone who has done that. I do know of people with t-5s behind built 350s who have had no problems with them. I have one behind my stock rebuilt 350 and drive it hard at times with no problems. I do keep a spare in the shed "just in case" though.

Granted. But behind a 455?

Anyway, Richmond makes an overdrive 5 speed now as well.

A T-"x" is no good behind a big Pontiac. Low-end torque will tear it right up. Agreed, though, IF one NEVER drives it "hard", it has a fighting chance. The T-5 IS a little better than the T-50, but not a lot.

I've seen several with the TKO-900 swap. Seems to be holding up behind the big Pontiac. Nice "kit", too. Everything fits as advertised, at least in a 2nd gen car. I'm sure the 1st gen "system" is as sorted.

The Richmond unit is the stronger offering available today.

Any way you "slice it", it is going to cost some money...

Jim

Thanks for the input, for now I guess I'll just stick with the Muncie. Thanks again, Jay

Relax people. I think I qualified my statement with "what are you going to do with the car". There are people who just like to drive around town. Others want to hit the track. Some want to do both. Should all of these cars be built the same? Shift habits, traction, and clutch choice all play a part in how torque is transmitted through the drivetrain.


Mike, the reccomendation of an M20 is a bit of a headscratcher since the original quesiton Jay asked was about a 5 speed. Unless my math fails me, the M20 falls a gear short. To some people, overdrive is critical. To others, its not. I'm assuming since he is asking about 5 speeds, then it is important to Jay.


If I read above, I actually think I said the TKO was a nice package. I just mentioned the cost. The TKO is about a $2000 transmission. That's a third of what I paid for my car. I think the swap kit for the TKO is around $3500. I paid $150 for my T5. I can rebuild several times for the same cost. Or,if I need to, I can swap to the GForce gear set for approx. $1000 and still be ahead of the game price wise and get slightly higher torque capacity then the TKO. Maybe $850 in savings isn't much to some, but it is to me.

There are many solutions to the same problem. Not everybody needs steel cranks, 4 bolt blocks, bulletproof transmissions and 9" rear ends. Its all about knowing what you want the car to be, and matching the parts accordingly to those needs. I would much rather go the route of the Gforce T5 and put the savings toward a vintage air kit so that I can have A/C while I'm cruising in overdrive on the highway. Others will want to strip the car down to get the best 1/4 mile time.

If I'm wrong, then I'm wrong. A member asked for an opinion and I gave it to him.

I said keep it and use a milder rear gear. Let me clarify my point.

Many people with 5 speeds in mind, are looking to keep the highway revs down. The nice part about having 5 gears is you typically get a nice deep 1st gear performance, coupled with a nice highway combination. Best of both worlds.

Now, if one does not care about performance enough to put a trans that will hold up to the occasional abuse of a high torque 455, then it should not be as much a concern to keep the 4 speed and run a gear like a 2.56, 2.73, or 3.08 either. Granted the off the line performance would be less, but what does that matter if you were going to have to baby it anyway?

The M-20 has a decently 1st gear to begin with, so even with a highway gear, when coupled with a 455 it's still going to get off the line pretty good.

Since only Jay is sure what is important to Jay, then it's nice to let him know there are other options. And others use these threads for their decisions as well. So this is food for thought for the OP and others. It all depends on goals and budget.

Yes, his question was regarding 5 speeds, but that doesn't necessarily mean it's because he wants to shift 5 times to get onto the highway.

As a wise man once said:

P.S. You can put in the G-Force gears, but the case is still a weak point. When the case flexes, the gears don't mesh properly, causing damage. So to really get a transmission with similar strength of a TKO or Richmond, you'd need to upgrade to their case as well.