I see a new or rebuilt tranny soon
 

Hearing new noises coming from tranny and sometimes grinds going into2nd and third. It does have a lot of miles on it.
My question is what trans would be better for my car , close ratio or wide ratio, M20 or M21??
-healthy cam, 230 duration, / 460 lift
-compression +- 11:1
- 390 rear gear
-26" tall tires

Thanks, Dave

I'd say a new TKO-600. Best thing I ever done to my car.

X2!Tom

I run an m21 with a 3:90 gear and like it fine. The 2.20 low first gear was made for rear gears like a 3:90.

but cruising @ 80 mph sux.....I went even worse....3.73's sucked ...feathering the clutch all the time. so 4.56....yay...all the way up till 45 mph. same m21...really need a M20 for this fat heavy 2nd gen f-body

The new TKX 5 speed is meant to fit without cutting the floor...that would be the solution I would use. When I broke my M20 I had another that I could've swapped in in a couple of hours but that wouldn't have gained me anything. I bought a Legend 5 speed(TKX was not yet available). I used to cruise 60 mph at 2800 rpm(3.55 and 26" tire) now I can go down the highway at 75 at 2400 rpm. Huge difference in cruising comfort and I'm not "in the way" at 60 or running too many rpm to keep up with traffic.

Tremec 5-speed all the way. I wouldn't even consider putting another muncie in the car. Leave the 3.90 gear in the car and enjoy no loss in acceleration and comfy cruising on the highway. You'll never regret it.

Now days, using tranny isnt a good thing, just sayin.
Don’t say I blew a tranny on the way in to work this morning.

TKX, TKX, TKX! Well worth the cabbage. Call Hanlon motorsports.

M-21 with your 3.90 gears. $600--$2000 vs $4000--up for a 5 speed. Depending how you use the car will determine if a 5 speed is for you. I run 4 speeds and Hurst shifters in my old cars. Like the shift feel and performance.

I've done a lot of things to my car...And the 5 speed is right at top of best additions.

I would go TKX hands down.

Do any of you have the TKX in a '61-'64 Catalina or other full size Pontiac? And you didn't have to cut the floor. How about shifter location is it the same?

I withdraw my question. I clicked around and see where the tkx has been installed in a number of '65 etc. GTOs. If it fits them with no modification to floor or shifter location it will fit the slightly earlier big car.

The new Tremec TKX is a game changer! I just installed it in my 65 GTO - one of the best upgrades I’ve ever made. You won’t regret it....

would a M21 be better for my car because of the cam I have or because of the rear 3:90 gears or both?
What differences in driving would be felt with either one??

The TKX will give you an 11.19 1st gear(2.87x3.9) vs the 8.58(2.2x3.9) in the M21. The TKX will give you a 2.65 5th gear(.68x3.9) vs a 3.90 with the M21. What's not to like about that? If you find yourself missing the M21 just start in 2nd and don't use 5th.

LOL that's funny

Go for the tremec. Not one person I've known has ever regretted it. Comments here bear that out.

I like a good Muncie but this day and age they are outdated. If you drive your car even a little bit you will appreciate that overdrive. Especially with 3.90's.
Being a stick already the swap isn't horribly expensive either.