CrCrzy

I have been looking to put overdrive into my 1960 and thought about the Tremec set up but didn't want to pay all that money for that transmission. I have swapped in a T5 into my 1975 Corvette which has a vortec headed 350 with about 375 to 400 horsepower. So far no problems from the transmission and it is driven hard. I have been wondering what would be required to install a T5 into my 60, and hopefully not have to cut anything especially since there is no console to cover anything up. Just a shift bezel. Well I decided to take the plunge this last week and this is what I cam up with.

Swap Details: one piece rear 350, '91 Camaro World Class T5

To start the swap, I removed the 283 and 4 spd.

Removed the Transmission mount plate and make an elongated slot out of the center hole. This will be the future mount point for the transmission.

Trim bottom ears off the bottom of the transmission, these are the ears that I think hold the torque arm. Removal of ears allows extra room to adjust transmission up and down

I used the camaro bellhousing which tilts the transmission at an angle. To use this with my stock exhaust, I had to trim the clutch slave cylinder mount off the bellhousing. I was not planning on converting to hydraulic anyway.

Clutch fork. I was planning on doing something similar to what silverslashstreak did with his clutch fork but I didn't think there would be enough room under my car. Instead, I took the camaro clutch fork and put it under the drill press and drilled a 3/8 hole in the center of the indention on the clutch fork. I will later connect my z-bar to the clutch fork by a rod with the end threaded. The threaded end will pass through the drilled hole in the clutch fork. Two 3/8 nuts will be used for travel adjustment. Similar to the set up on my 67 Camaro

The next step was the hardest for me. Cutting the tunnel at the shift bezel. This car started off original and I was hoping to not have to cut fiberglass. Referencing a Tremec install, some owners (not all) have had to cut out the ash tray pocket to allow install of the transmission. I was prepared for this but was hoping I would be one of the lucky ones who would not have to cut it. Well, I wasn't. So instead of just cutting the ash tray, I decided I would cut the tunnel around the shift bezel, about 1-2 inches around the perimeter of the bezel. (I will go into further details of this a little later)

After I tastefully butchered the floor I began to install the transmission into the tunnel laying on my back with the car on jack stands. Not very fun. I first placed the tailshaft on the X-member, then I installed the bottom transmission mount plate (which was previously modified). I used longer bolts to mount this plate so I would be able to adjust the rear height of the transmission up and down once the engine was installed.

Next I installed the engine, adjusted the rear tailshaft of the transmission where I wanted it in the tunnel, and then measured for my driveshaft. Having my tastefully butchered hole in the tunnel really made it easier for me to mate my transmission to my engine.

The rest of the install is straight forward.

Things left to do:

Because I did not use the stock Corvette bellhousing, I will have to make a mount to locate the ball stud pivot point for the z-bar. This should be easy, there are two bolt hole provisions on the side of the block I can use and then locate exactly where I need my ball stud. Once this is done I can make the threaded rod to attach the z-bar to clutch fork.

Cover up the hole in the floor. Instead of cutting the ash tray out I cut around the perimeter of the shift bezel about 1-2 inches out. From here I will pop a mold off the piece I cut out. I will then take this new fabricated piece and then locate the shift hole exactly where I need it. If you look at your shift bezel stock location it is more toward the driver side. Where the shifter comes through the floor with the T5 install, it will place the shift bezel more toward the exact center. Once I locate this and establish final transmission height, I will finalize my new floor center section and make it a screw in peice. I also plan to make a mold of this modified floor section in case anyone in the future decides to do this swap. I did this for two reasons. One, in the event I ever revert back to the four speed I still have the original floor that I can cleanly glass back in. Two, having the hole in place simplifies install of the shifter itself as well as transmission install. Hopefully I won't look back at this and kick myself in the butt. But, In all reality it does not look bad so far, and I should be able to easily return it to original by fiberlgassing the original tunnel piece back in place. However, I don't think I will ever do this because I don't think I will ever sell the car. I am building it for me and my dad to enjoy. We have already built it back original once and were never totally happy with it

Things I would have done differently:
One thing I would have done different is possibly look into using a mustang T5 with an adapter plate similar to the one norvalwilhelm has built. This would allow you to use the stock bellhousing which in turn would leave the z-bar bracketry untouched. The additional 1/2 inch thickness of the adapter plate would not effect clearance at the back of the transmission. Furthermore, this transmission was originally installed straight up and the bottom mount will be flat instead of tilted. Once you make an elongated slot into your transmission mount plate, this transmission will basically bolt in with little future modification.

Sorry no pictures at this time, I will take them once the swap is complete. Planning to be finished by the weekend. While this swap is definitly possible without drastic modifications it is not for the purist. Would it have been easier to go with the Tremec? Probably so. Was it a whole lot cheaper going with T5? Can easily be duplicated for under $850....125 for clutch, 50 for driveshaft shortening, 6 for transmission mount, 15 for ATF........Total about 196 dollars and whatever you buy the transmission for.

magicv8

Great post - thanks.

When the job is done, will you be able to remove the trans and clutch housing without removing the engine?

When I got my 66 the prvious owners had put a th400 in it, and the only way it could be removed was to pull the engine.

DZAUTO

That's why I've elected to just stay with an M20 and 3.08 posi behind the SB400 in my 56. NO MODS REQUIRED and gas mileage isn't that bad, depending on how I drive, I can get 17-19mpg hiway.
Everything remains a simple bolt on fit!

CrCrzy

Magicv8, from what it now seems like with the screw in tunnel cover, I think I will now have enough room to slide the transmission back, lower the rear of the engine, raise the rear of the transmission and pull her out. This was another thing that ran across my mind before cutting the hole. I have read some of your post and I think we have a lot in common in that we drive our cars a lot. Are in a lot of places away from home and would like to build our cars in a way that we can fix it anywhere in the country from parts at the local auto store. I read about your electronic fuel pump install. Can you PM me about the details of the pump and the horsepower output of your engine. I am thinking about running that pump, I have found one in every auto store I have stopped by.

Dzauto, thanks for the reply. I had a 4 spd in two of my previous cars, 67 Camaro, 74 Vette and it was fun to drive around in but I never liked the highway. Because I am on the road so much, both cars ended up with 3.08's. Definitly felt like I gave up all my low end to marginally gain something on my cruisability. On my 75 Corvette, originally a 4 spd but when I got it there was a TH350 in it. This car has a 3.08 rear and a T5. The T5 I believe off the top of my head has a 2.95 first gear, multiplies out into the 9.086:1 with the rear. I have read somewhere that for a street car with a redline under 6000 rpm that the optimal first gear multiplication is 10:1, with this set up I am very close to this and the car is very quick out of the hole and easy to drive around town. On the highway I have 30% overdrive with my 3.08, I think this effectively makes it a 2.156:1 final drive. Very low cruise rpm. The car gets in the neighborhood of 22-24 mpg. The engine is also a vortec head 350 which if I remember correctly has .477 lift cam. Very similar to the ones the magazine built up which made 375 to 400 horsepower. Now this exact setup going into my 1960 Corvette should be even better, the car is much lighter than my 1975 Corvette. Thanks for the replies and I hope all this work can help someone out there.

silverslashstreak

Jupiter, I tend to agree with you, the next T 5 I do I think I will go with the Ford for the reason you mentioned that you don't have to rework thw zbar and clutch linkage. Also I have found a place you can buy the adapter plate for a couple hundred bucks. Another good thing about the ford is it is about 1.5 inches more forward on the shifter location.

I was like you I always ran a 3.08 for the highway but now I am running a 3.36 and thinking about a 3.70. My T5 and I think most Camaro v8 t5 have a .38 overdrive which is a little to high for my taste.

It is so much more fun to drive now, smooth shifting and smooth and quiet at 80. Next to jeep steering box best mod going for old corvettes.

SSS

wmf62

i'm still fond of my MY-6 3spd w/overdrive. running 1970 350 LT-1 with 3:36 rearend. easy bolt-in, less gears to shift....
Bill

JohnFromVentura

Are there any good web sites that have pictorial differences between T5 and late Tremec Transmissions? I couldn’t physically get a Keisler to fit in my 57. Thanks for the good write up ... add pictures when you get them please!

silverslashstreak

The T5 is much shorter from the center line of the trans up to the top of the trans than the Tremec. So you can install the T5 higher in the tunnel, at the same time decreasing the ujoint angle at the slip yoke.



My T5 at work SSS

CrCrzy

Johnfromventura, when you tried to get the tremmec into your car what kept you from being able to put the transmission in? With the T-5 set in at an angle without the floor board cut out, the transmission was hitting the ashtray pocket. I guess this is what the tremmec is comming in contact with? From what I have read some people installing the tremmec have had to cut out the ashtray and some people haven't. My only guess as to why some people have clearance problems and others don't is probably related to the mounts they use. I used the stock mounts (stiff paperlike material and a metal shim), maybe some other people have replaced these mounts with rubber giving them more clearance? I think if the floor was 1/4"-1/2" higher the transmission would have fit no problem without cutting the tunnel out. My guess is this is what the owners who have not had to cut the ashtray out are dealing with. Maybe a previous owner had replaced the mounts with a more dampening friendly rubber. I thought about doing this, but like I outlined in my previous post I had other reasons that also led me to cut the floor out. If I had not wanted to cut the floor and shimmed the body up a half inch, I think I could have gotten away with a shifter assembly like the one SilverSlashStreak made. Only problem would have been trying to install the transmission with the shifter bolted together. It would have been tough, and probably about impossible if the engine was still in the car. Maybe some of the owners of cars with the tremmec installed without the ashtray pocket cut out can comment on what type of mounts they have on the cars.

Sorry no pictures yet, I am out of town for the week and won't be able to get back at the car until hopefully next week

CrCrzy

wmf62, do you have a picture and/or dimensions of the ball stud bracket that you used on you MY-6 conversion? I have to fabricate a bracket as well as a clutch fork pushrod. Thanks

OCS1667

I have read with interest about the T.-5. I hate to seem simple because I think I know what you will say, but nobody mentioned the drive shaft. How much do you alter the original or do you just get a new one.
Dennis

JohnFromVentura

I cut my ashtray off by at least 5/8 of an inch (this really violated me).
The ashtray wasn't interfering at all. The 2nd cover back interfered with the floor! I talked to someone that installed a Keisler conversion in a 62 at the SACC Truckee convention. He got his to fit by grinding a 3/8 x 3/8 chamfer on the outer edges of this cover He said his friend got a Keisler to fit by dropping his engine 1" but his drive line angles were all screwed up. Any feel for what the center of the main shaft is to the top of a T5? I used the rear mount that Keisler supplied. This was identical to a C1 3 speed mount. The mount wasn't the problem ... interference with the floorboard and the Keisler modified Tremec was the problem1

OldDog58Vette

Thay let you drive that fast in Arkansas............

CrCrzy

I had a driveshaft that I already had in possesion shortened. 50 bucks to shorten.

I don't think I specified the mount I was talking about to gain floorboard clearance. I was not talking about the mount to the engine or transmission. I was talking about the body mounts. The stock mount is a thin stiff paperlike material and a metal shim. I was thinking that maybe some owners who have been able to install the Keisler without floor modification may have changed the body mounts away from stock and maybe the mounts have been replaced with thicker rubber. This could have given them the 1/4"-1/2" vertical clearance that I think would have cleared the transmission, T-5 or Keisler. This is the only variable that I can come up with to cause some owners to have clearance problems and others to not have clearance problems. If you do not want to cut the floor in your Corvette I don't think the T-5 would be a realistic swap. Even if you could gain enough clearance, which I think you could with rubber block mounts, it would be very difficult to install the transmission with the shifter bolted onto it along with the shifter adapter. Installing the transmission in this manner with the engine installed seems to me like it would be just about impossible, not so bad with the engine out of the car. This is where I think you would benefeit with the Keisler. The Keisler, from what I have read, has a special shifter that can bolt in with allen screws from the top. This along with the additional clearance from the higher body mounts I think would cure most/all the Keisler problems. I can not say this for sure, but if my "theory" is correct and if I am understanding the Keisler problems correctly the additional height of a rubber block mount would probably work. I originally wanted the Keisler for myself but when I added things up I could have spent $3000+ on the Keisler alone or I could have a 350 built complete and engineer a T-5 conversion for about the same amount of money....which I did. Hopefully I can get back home next week and put this thing to bed and take some pictures for everyone

Plasticman

JUPITER60,

It depends on what bellhousing you are using, and if you have the threaded hole on the side of the engine block (used for later model stud pivot mount - both WMF62 and I have later blocks). I used a "standard" C1 stud bracket (the one with the 2 holes that bolts to the side of the C1 bellhousing), but made a bracket to tie it into a bellhousing that did not have the 2 threaded holes (early truck cast iron bellhousing with the bottom open like a C1 bellhousing). I also welded on another piece that used the above mentioned engine block stud bolt hole (so that the stud bracket was properly supported).

WMF62's bracket was different since he used the aluminum bellhousing that came with the MY6 trans (full circle type).

Here are some pictures of the bracket and welded on piece (to give you an idea of what I did), but I don't have one with the triangle shaped piece welded to the top of the stud bracket). Note also that the rear threaded hole to mount the stud bracket has not been drilled yet in the pictures below! It went into the "block" of steel, but I had not properly located it when the picture was taken.









Plasticman

CrCrzy

Plasticman, thanks for the reply. I was very close to installing the MY-6, I actually bought the rear yoke to make the swap possible. Only problem with the MY-6 was trying to find one. Every one I found was up north so whatever I would have paid for it, I would have paid additional money for that type of shipping to Florida. I am still keeping an eye out for it. I think I mentioned this earlier in the post, I have a one piece rear block. This particular block has to ball stud hole provisions, I was planning on using these two holes as mount locations and then locating the position of the ball stud. It seems nice and straight forward. Now if I would have just used a Mustang T-5 with an adapter plate, I would have been able to use my stock bellhousing and not have to do what I am doing now. Live and learn, but for now I am sure I can engineer something to work