Let's talk Transmissions

[PCW]

Working with Peter to finalize my build cost and I have most of my build nailed down. Still deciding on the engine builder, but the car will be a FIA 289 with either a 331 or 363 ci with an 8 stack carb weber set up, targeting approx. 425-450 HP. The biggest question I still have is what trans to use.

I have had a lot of appreciated advice from the Facebook Group regarding engines and weber carbs vs weber EFI and decided to go with the carbs. Troy stated use the TKO600 w/the .82 final drive. But I keep finding threads about the Toploader (TL) and the Richmond Super Street 5 Speed (RSS), I see positive comments for all three.

So my plan at this point is to use on the street, but, I want to future proof the car as I feel I'm going to want to track it sometimes. I adding the ERA rear end, BIG brakes and the discussions with the engine builders have been a balance between a street/track motor. With all that said, what are your thoughts about transmissions? Pros vs Cons, likes and dislike etc..

Thanks Craig

[fastd]

First, reconsider efi over carbs. I have the holley sniper efi (don’t know about weber efi), and especially for the money vs the weber carb set up, it is an absolute no brainer.

Second, the tremec with the .82 is a much better choice than the .68. Having said that I have the tremec 6 speed with both gears.

I think the top loader is a relic of the past - bottom line: don’t torture yourself without overdrive gears.

[Karl Bebout]

I'd certainly go for the 6spd. The two OD ratios will make highway cruising much more pleasurable while still having pretty decent lower gear spacing for the track.

[PCW]

What Tremec 6 speed do you have? TREMEC TR-6060, TR-3160? Also, your EFI is a carb looking version, right? I was looking at the EFI 8 stack that weber make, but decided on the stack carbs...

[fastd]

My efi is the carb (throttle body) type. I think the efi stack type look great. Switch to efi! My holley set up permits electronic distributor that allows adjustment of the timing through the interface which helped with hot cranking. The efi helps offset several problems I had with carbs including fuel boil, vapor lock, hot start, flooding.

I think it’s the 6060 - I’ll check that in the morning.

[olddog]

How many rpm are you building the engine to peak the Hp? Or more precisely, how many rpm will be you shift point? It matters.

The TKO 600 (which I have one), does not shift as good as it should above 6500 rpm. Some say a little less. There are experts who can modify the transmission to shift much better and at much higher rpm. A used TKO sent in to be modified, would give you a better than new unit for about the same price as new. Maybe less, if you get the right deal.

I suspect every transmission out there has something less than ideal, under some conditions. I cannot tell you specifics.

The Tremec six speeds may be a bit too long to fit in some Cobras, especially if a live axle is used.

You might want to expand your knowledge quest into some of these other areas.

Good luck.

[xb-60]

I'm fitting a Toploader to my FIA replica. I figured with a very light car and no shortage of power, I don't need a stump-puller first gear, so I have a 2.92:1 rear end. The effect should be like a five speed box without first gear.
Although it's not a T10 (unobtainable here), it's close enough for my purposes. In "bench testing" it shifts beautifully too.

Cheers,
Glen

[eschaider]

The T-56 Tremec 6 Speed transmission with the 2.66:1 first gear like used in the 2003/2004 Supercharged SVT Cobra's will be an absolute pleasure to drive. It seems to have a right gear for just about anywhere you find yourself.

Don't think of it as a 6 speed, think of it as a 4 speed with two overdrives — which is what it really is. The gear spacing is very attractive and the transmission in OEM form is stunningly strong. If it has a weak point it is the input shaft and Tremec offers a 23 spline large diameter upgrade that most of the performance crown has installed.

This is what one looks like;



The actual trans above is the T-56 Magnum and has much wider gears than the non-Magnuml T-56. Tremec no longer shows the non-Magnum T-56 on their website so the Magnum is likely the only game in town today.

The T-56 Magnum is rated at 700 ft/lbs of torque. It is a brute and they used an impressive triple cone synchronizer on the transmission. When you shift even at 7500 rpm it is like a hot knife through butter. Another benefit of the Tremec Magnum version is the availability of five different gear ratios, The first gear offerings are, 2.97 and 2.66 from Tremec. Rockland gear offers three special 9310 nickel steel Tranzilla gear sets cut at a 22˚tooth angle with first gear ratios of 2.98, 2.71, 2.62 and 2.29.

The Rockland gears used in their Tranzilla 6 speed are rated as 1000 ft/lb of torque gear sets if you use a Viper mainshshaft. You can get a used normal T-56 and buy the Rockland gearset and come out about the same as a new Tremec. The difference is the 2.62 and in particular the 2.29 gear sets.

The 2.62 is a very nice close ratio set pretty evenly matched between gears. The 2.29 gear set is (rpm drop-wise) like the gear sets used in the large diesel tractors where you hear the engine sound like it has the exact same rpm drop between every shift. The 2.29 gear set is a to die for gear set. You won't need the strength but you'll love changing gears — magnificent doesn't do it justice.

If you go the TKO 600 route you need to get Liberty's shift rail timing upgrade, the carbon fiber synchronizers and the countershaft front bearing modification. The front bearing mod is reliability, the other two are shift quality.

If you go the TKO route definitely get the 0.82 overdrive unit. The transmission is sometimes referred to as the Road Race version. The 0.64 overdrive is not as nice a driving experience because of the big gulp from 4th to 5th. With the 0.82 OD the gear change just feels like the next gear — much nicer driving experience.

This is a pic of the TKO;



Although the other transmissions are period correct they do not provide as good a driving experience. The 6 speed T-56 is by far the best driving experience of all. It just feels like you always have the perfect gear ready for any road condition you encounter.

I have a Liberty modified 0.82 OD Tremec TKO600. The difference in shift quality from an OEM Tremec TKO is nothing short of stunning. That said, the way Tremec and the aftermarket have developed the T-56, I wish I had a T-56 today — which I may convert to anyhow.

If you like the shifter positioning of the 2xxx generation Cobra's shift lever, either the TKO or the T-56 transmissions offer a mid shift position that will closely duplicate the original shifter position.


Ed

[KDubU]

I had a TKO600 provided by Forte Parts and she shifted very nicely. On the highway at 70 she ran at 2000. I have heard the T56 Magnum is a nice transmission and can handle HP.

[Grubby]

I don’t think the 6 speeds will easily fit in an ERA.

John

[blykins]

I'm not a T-56 fan and never really have been. They are longer than a TKO, bigger around, and heavier. I have also never really seen a situation where you need two overdrives.

For a SBF making 425-450 hp, the torque will be down around 375-400 lb-ft. You have lots of options there: a TKO 600, a worked T5, or a Toploader.

The T5 and the Toploader are the best shifting transmissions out there, bar none. The TKOs are a little notchy, but better when they break in, and are even better when they are modified internally.

For a peakier engine, (read shifting over 6000 rpm), I would recommend the internally modified TKO 600 if you go that route.

Depending on the rear gear ratio and where you plan on driving the car the most, a Toploader makes a VERY nice drivetrain complement, and if you go with the factory 289 block/factory heads, the drivetrain would all look period correct.

I have seen more and more guys opting for completely period correct builds, especially in the nice cars like the ERAs, Kirkhams, etc.

[fastd]

OP: Mine is the T56 Magnum with 2.66 first, .80 5th and .63 6th.

To xb-60, what ratio is the 1st gear on your toploader? the close ratio has a 2.32 first gear and the wide has 2.78. I generally agree with your speed is really like a 5 speed given your gearing; but I would still recommend a five speed; your 2.92 is a nice 60-70 gear but not really a cruise gear; if you a doing 75 on the highway for a decent stretch then a 5th gear would be nice.

[fastd]

I've have the toploader (in a '68 mustang), tko 3550 and the T56 magnum - I don't mind the way the T56 shifts; never really noticed it as a "problem". However, when I had the toploader, I always wanted another gear.

As far as period correct, I think everyone starts out thinking "I want as close to original as possible" but after living with it a while, I started to think, "why compromise? get the transmission and efi to make it more fun to drive everyday; that extra gear doesn't impact the originality more than the pleasure I get from having those extra gears"

[desgros@vtlink.]

Grubby - Exactly. When I spoke with Peter about my Slabside that is what I was told.


John
ERA #3010 Slabside 289 BRG

[8litercobra]

I replaced a close ratio toploader with a T56 magnum. The T56 is big, but it fit in my Unique FIA with no mods, except modifying the rear crossmember for a different tranny mount. You'll have to do that with any transmission change. Also, obviously, had to mod the driveshaft

Rockland Standard built my tranny, and I have the 2.29 gearset. I wanted to get as close as possible to the toploader close ratio:
2.32, 1.69, 1.29, 1.00. I was afraid that a lower first would result in a first gear nearly like a pit gear. The gearset from Rockland is 2.29, 1.60, 1.21, 1.00. I'm happy with the result.....I can't tell much difference.

Since I was adding weight with the T56, I just had to swap out my iron block and heads 351W with a new one using a Dart aluminum block. 438", Kaase heads. I've been very pleased with that too.

Brent Lykins was very patient in working with me (I changed the setup more than once) to get the clutch/PP/etc I needed to make it all work (even though he isn't the biggest T56 fan!)

[fastd]

Originally Posted by 8litercobra

I replaced a close ratio toploader with a T56 magnum. The T56 is big, but it fit in my Unique FIA with no mods, except modifying the rear crossmember for a different tranny mount. You'll have to do that with any transmission change. Also, obviously, had to mod the driveshaft

Rockland Standard built my tranny, and I have the 2.29 gearset. I wanted to get as close as possible to the toploader close ratio:
2.32, 1.69, 1.29, 1.00. I was afraid that a lower first would result in a first gear nearly like a pit gear. The gearset from Rockland is 2.29, 1.60, 1.21, 1.00. I'm happy with the result.....I can't tell much difference.

Since I was adding weight with the T56, I just had to swap out my iron block and heads 351W with a new one using a Dart aluminum block. 438", Kaase heads. I've been very pleased with that too.

Brent Lykins was very patient in working with me (I changed the setup more than once) to get the clutch/PP/etc I needed to make it all work (even though he isn't the biggest T56 fan!)

what rear gear ratio do you have?

[Grubby]

I would seriously consider a T5 for a small block like yours.

The reasons;
1. TKOs have a mixed bag reputation. Google it. Some shift really poorly and I had two of them.
2. T5s have a great reputation for good shifting. They are not strong enough for big blocks.

The other problem with 6 speeds is the amount of overdrive. Most hot rod type engines can't run a low enough RPM to use it unless you are going 120 mph.

John

[Anthony]

Originally Posted by PCW

Working with Peter to finalize my build cost and I have most of my build nailed down. Still deciding on the engine builder, but the car will be a FIA 289 with either a 331 or 363 ci with an 8 stack carb weber set up, targeting approx. 425-450 HP. The biggest question I still have is what trans to use.

I would think Peter would be able to give you the best advice. I think any of the transmissions will work, the main thing is to match the tranny with the appropriate rear gear.

The only advice I have, is that if you are going to go with a toploader, and you think at some point in the future you may change to an overdrive tranny, I'd make sure the frame/crossmember is done correctly now, if needed, to accommodate any future tranny swap.

If you are going to buy a new/ rebuilt toploader, I'd go with david kee.

[Anthony]

Originally Posted by blykins

I'm not a T-56 fan and never really have been. They are longer than a TKO, bigger around, and heavier. I have also never really seen a situation where you need two overdrives.
.

They are an excellent beefy tranny for high torque motors where you want the best highway cruising. Perfect for the viper / vette / etc. especially if it's more of an everyday type of car.

[Grubby]

Originally Posted by Anthony

I would think Peter would be able to give you the best advice. I think any of the transmissions will work, the main thing is to match the tranny with the appropriate rear gear.

The only advice I have, is that if you are going to go with a toploader, and you think at some point in the future you may change to an overdrive tranny, I'd make sure the frame/crossmember is done correctly now, if needed, to accommodate any future tranny swap.

If you are going to buy a new/ rebuilt toploader, I'd go with david kee.

Good advice and I can tell you the ERA 427 has an "adapter" that bolts in to accommodate a Toploader. It isn't installed if you use one of the Tremecs. It would come with the car if you told Peter you were going to install a Toploader.

I actually swapped 755 from a Toploader to a TKO 600. It was very simple.

John