TKX or T56...Looking for input

[brickyard69]

Looking for input......

Installing a 495hp LS3 in a 1968 Camaro with ridetech/Curry setup. Stock subframe.



I am torn between installing a T56 or a TKX. I am doing this project on the side of my house, and am a little hesitant of cutting out the trans tunnel. I don't plan on going on any long cruises (mostly around town). I do have a welder. Is it very complicated? Just looking for input on the TKX. Am I being a p***y by not going for the T56. I feel like it

Steve
Scottsdale AZ

[dontlifttoshift]

TKX all the way in your case.

[Pedigry]

TKX. Smaller and lighter, makes getting engine angle and pinion angle less. You won't miss 6th gear unless your doing alot of highway, high speed touring. I will be putting one in my 575 HP mustang. It's a solid trans. T56 is awesome for big power motors, 700 plus. but if your less than that, the benefits of the TKX are undeniable.

[TheBandit]

I think a TKX is the right choice for you, but I'll offer my experience with a close ratio Magnum-F since I think there are a couple benefits. My car has 3.73s and 25.6in tall tires.

First, I often find myself cruising in 5th gear, meaning I am splitting 1:1 4th gear and 0.63:1 6th gear by using the intermediate 0.80:1 5th gear. This is usually on backroads where I'm going maybe 50-60mph and 6th is just a little too much overdrive, but 4th has the engine reving slightly more than I'd like. There is a roadway I drive often near my house where the speed limit is 45 and I find myself chugging along in 5th gear at about 50-55mph. This makes it a sort of Goldilocks in between gear for those scenarios, but we're only talking about a 500-600rpm difference at that speed so it's not a big deal.

Second, the shifter location on the Magnum-F is much further back the TKX and a bit further back from a standard Magnum. For me, this puts the shifter in a perfect position so I can use a short 6" lever and feel very comfortable/connected with the shift mechanism. I think with the TKX you might have a longer swept-back shift lever, which may feel less direct compared to having the shift mechanism right below your hand on a shorter lever. You really have to measure your car to see where the shifter will be located and make a decision that suits your ergonomic needs. For reference I'm 6'0" tall. I think spending time locating the shifter and even mocking up different lever lengths and offsets well worth the effort to get a car that is comfortable and fun to drive.

All that said, considering the price difference, the additional work to modify the tunnel (I cut mine out completely and rebuilt it), the additional weight of the Magnum, your power level, and the fact that you just want to cruise around town, I think the TKX is probably the right choice for you.

[MadGoat]

TKX all the way for your build. Good luck.

[Just 1 More]

T56 for all the reasons Bandit just explained 1:1 is not enough, the jump to .68 or .63 is too much so the .80 5th is a good place to be

[gsxrken]

I think the TKX is going to cannibalize a lot of T56 sales. The TKO shifted like a truck, and often required tunnel modifications anyway, and so a case could be made for some to step up to the $$$ T56 plate. But the TKX shifts just like a T56, is much smaller and avoids most tunnel hacking, and is available in 3 different overdrive ratios. I’d get the .81 myself, since my TKO has a .68 and as someone mentioned, it’s too tall and too much of a drop from 1.00 4th.

[Barrongi]

I have the tkx in 69 camaro (no mods needed) with 450hp. Fabulous all around.

[130fe]

If you are using the Holley mounts (and all of their other install parts), its a no brainer to use the T56. Holley make a t56 crossmember and the tunnel isn’t required to be raised in that LS swap situation. They (Holley) don’t make a TKX compatible crossmember. I think in situations where using a T56 would require raising the tunnel, the TKX is a great alternative. I have had the stock sub with Holley components with an F body LS Trans and then a magnum. No mods to the tunnel were required. When I switched to a DSE sub, it was “required” to raise the tunnel (and I had no issue with it).

What gear and tire sizes are you considering? What is your target cruising speed vs RPM? I don’t understand- if you aren’t considering long cruises then why are you even looking at an overdrive trans?

[brickyard69]

I am still undecided on T56 or TKX.

If I go T56, which transmission tunnel is preferred? Speedtech or Bowler?

[TheBandit]

Speedtech has an abrupt 90 degree transition at the rear of their tunnel patch while Bowler has more of a tapered transition. Personally I think the longer transition looks better, but will require a little more fitment work. Speedtech has a flange on the sides of theirs which is pre-punched for spot welds, which could make it easier to install.

After looking at both of them and a few other custom tunnels online, I decided to make my own. I built in a pair of access panels which makes it easy to remove the shifter and access the bellhousing bolts. I've seen a lot of people suffer from leaky shifters, so definitely consider adding an access panel in that area.

[Just 1 More]

I used the Speedtech tunnel, The abrupt end fit perfect with my console. I used a trimmed CV boot for the tunnel hole, just stuffed 2 bellows in to the hole and zip tie the top. Made a little bracket to mount the console to the tunnel.
20220515_170550 by F G, on Flickr
20220520_180848 by F G, on Flickr
20220522_142035 by F G, on Flickr
20220522_143642 by F G, on Flickr

[ryeguy2006a]

I am still undecided on T56 or TKX.

If I go T56, which transmission tunnel is preferred? Speedtech or Bowler?

If you install the LS3 using Holley's mounts and oil pan, you DO NOT need to modify your transmission tunnel. I installed both a T56 and a TR6060/T56 Magnum in my 1968 Camaro with ZERO transmission tunnel mods. It is very tight, but it all fit. So IMO, I would say to go with the T56 Magnum if you are going between the two.

[BonzoHansen]

Does that mean the holley mounts move the engine further forward than other mounts?

[brickyard69]

Does that mean the holley mounts move the engine further forward than other mounts?

I used the Holley mounts but still had to cut some of the tunnel to get the trans high enough so my driveshaft angles were in line.

I made a small patch/tunnel cover myself.