anyone running a tremec 6 speed?

[Ruscal]

Ryan,
Here are some pics of my install. Shifter relation to seat. Shot of under floor near shifter. My engine is back pretty far, and also lower than stock, so front shifter position is still close to seat.
Russ

[Ruscal]

Shots of cross member and mounting. Last shot shows trans belly hanging below frame 2".
I traded some ground clearance for lower CG. Exhaust x over pipe mimics trans cross member dipping under tail shaft.
Russ

[Ruscal]

Crossover "H" pipe behind cross member. Dialing in scatter shield bellhousing.
I have some shots of clutch related tasks I can post if anyone is interested.
Russ

[Ruscal]

Double post. Keeps popping up.

[ryans69chevy]

Wow that looks pretty sweet! Did you ever try the middle position or go right for the forward most? It looks like the middle wouldn't even work. Looks like the forward seems to be the right position for a bench seat.

I read in another thread that an auto crossmember works for this tranny. Just needs to be brought back a couple of inches towards the rear. Do you have any knowledge about that?

I also have been reading through peoples build threads and finding out they are going with a little steeper gear ratio in the rear end than I would imagine. I was planning and was recommended to put in a 3.73 ring and pinion which I thought would be great, but finding out that other people are putting 4.11 even 4.56 has me wondering if my choice is the right one.

I looked through Mark's build thread which was in the same position as me with the 3.73's. I clicked on the link he had which was grimmjeeper. I typed in all the info and it with the 3.73's in 6th gear it's like 1400 rpms at 70mph which for a carbed engine is almost lugging the thing. I went to 4.11 and then 4.56 which now is 1700 rpms which still seems a little low to me. Anyone have any helpful ideas or how to figure this out? My engine is a 489 with a 650 Holley double pumper mech carb with a comp cam roller. It looks like I'm getting the close ratio t56 6 speed magnum.

[sangell]

Originally Posted by ryans69chevy

Wow that looks pretty sweet! Did you ever try the middle position or go right for the forward most? It looks like the middle wouldn't even work. Looks like the forward seems to be the right position for a bench seat.

I read in another thread that an auto crossmember works for this tranny. Just needs to be brought back a couple of inches towards the rear. Do you have any knowledge about that?

I also have been reading through peoples build threads and finding out they are going with a little steeper gear ratio in the rear end than I would imagine. I was planning and was recommended to put in a 3.73 ring and pinion which I thought would be great, but finding out that other people are putting 4.11 even 4.56 has me wondering if my choice is the right one.

I looked through Mark's build thread which was in the same position as me with the 3.73's. I clicked on the link he had which was grimmjeeper. I typed in all the info and it with the 3.73's in 6th gear it's like 1400 rpms at 70mph which for a carbed engine is almost lugging the thing. I went to 4.11 and then 4.56 which now is 1700 rpms which still seems a little low to me. Anyone have any helpful ideas or how to figure this out? My engine is a 489 with a 650 Holley double pumper mech carb with a comp cam roller. It looks like I'm getting the close ratio t56 6 speed magnum.

My son's truck is not done yet but it's t-56 has the .56 6th gear with 27" tall tires and we went with 4.56 gears. I think for you 1700 RPMs at 70 mph is not a bad place to be.
The thing you need to watch for when going with even lower gear is the drive shaft RPMs start getting real high. Our set up is 3300 drive shaft RPMs at 75 mph which is pretty high.

[NC_John]

Originally Posted by sangell

My son's truck is not done yet but it's t-56 has the .56 6th gear with 27" tall tires and we went with 4.56 gears. I think for you 1700 RPMs at 70 mph is not a bad place to be.
The thing you need to watch for when going with even lower gear is the drive shaft RPMs start getting real high. Our set up is 3300 drive shaft RPMs at 75 mph which is pretty high.

You could probably even run 4.88's and still have a somewhat useable 1st gear. I'm trying to learn how to launch the truck with 4.56's without spinning. Burning the rears all the way through first is a hoot but won't be the fastest way down the dragstrip.

[ryans69chevy]

Hmmm that's interesting. I guess I never thought about driveshaft rpms. How might one figure that out?

I forgot to mention I'm doing right about a 30" wheel. I know that plays a big factor in all this.

[ryans69chevy]

I just talked to american powertrain and went through the calculator with him and was told I'm gonna be at 2000 rpms at 75 mph with 3.73 gears and 30" tires. I am getting the tuet11009 transmission which is the close ratio. They also said if I went with a 4.56 my first gear would basically be unusable.

Does anyone else have about the same experience with this? One calculator tells me one number and the other tells me a totally different number.

[Ruscal]

Originally Posted by ryans69chevy

Wow that looks pretty sweet! Did you ever try the middle position or go right for the forward most? It looks like the middle wouldn't even work. Looks like the forward seems to be the right position for a bench seat.

In second gear my shifter is only about an inch from the front of my middle seat, so forward position is best in my truck. Your truck is different, so take some measurments from the back of the engine to see which location is best for you.

I read in another thread that an auto crossmember works for this tranny. Just needs to be brought back a couple of inches towards the rear. Do you have any knowledge about that?

The T400 cross member would have worked, but it needed to be lowered about 2" in my case. My auto cross member was straight, so plates would have had to hang down 2" below the frame channel. I thought a "V" cross member would be more sano, so fabbed a new one. Moving a factory one fore and aft should be easy if drill access is available. My case is different than most, since the engine is dropped and moved back. That changes trans position downward and back and requires a shorter drive shaft. Cornering ability was important to me, so lowering the CG helped.


I also have been reading through peoples build threads and finding out they are going with a little steeper gear ratio in the rear end than I would imagine. I was planning and was recommended to put in a 3.73 ring and pinion which I thought would be great, but finding out that other people are putting 4.11 even 4.56 has me wondering if my choice is the right one.

I looked through Mark's build thread which was in the same position as me with the 3.73's. I clicked on the link he had which was grimmjeeper. I typed in all the info and it with the 3.73's in 6th gear it's like 1400 rpms at 70mph which for a carbed engine is almost lugging the thing. I went to 4.11 and then 4.56 which now is 1700 rpms which still seems a little low to me. Anyone have any helpful ideas or how to figure this out? My engine is a 489 with a 650 Holley double pumper mech carb with a comp cam roller. It looks like I'm getting the close ratio t56 6 speed magnum.

My truck has 4:11 gearing with close ratio magnum and smaller diameter tires. I can't remember what my tire diameter is. Nitto 555's 265 50 rz18 I think. somewhere around 27.5". My freeway RPM's are pretty high, around 2600 @ 75. I like the way the 4:11's accelerate, and first gear is usable and not too low, but freeway driving could be helped by taller gears. If I went to 3:9 gearing the freeway would be improved, but first gear would be harder to take off. I plan to pull a small travel trailer, so I think my gearing is optimized as is. I think the wide ratio magnum is too extreme the other way, so close ratio is best.
The gear ratio chart provided by your dealer should be reliable. Its just math. Some tires grow a little at speed, so chart is approximate. Inflation also is a variable..

Russ

[sangell]

Originally Posted by NC_John

You could probably even run 4.88's and still have a somewhat useable 1st gear. I'm trying to learn how to launch the truck with 4.56's without spinning. Burning the rears all the way through first is a hoot but won't be the fastest way down the dragstrip.

The T-56 we have is out of a CTSV so its a wide ratio with a 2.92 1st and .56 6th and with a 27" tall tire 4.88 would be a little too low IMO.

Originally Posted by ryans69chevy

Hmmm that's interesting. I guess I never thought about driveshaft rpms. How might one figure that out?

I forgot to mention I'm doing right about a 30" wheel. I know that plays a big factor in all this.

Engine RPM/trans gear ratio

Originally Posted by ryans69chevy

I just talked to american powertrain and went through the calculator with him and was told I'm gonna be at 2000 rpms at 75 mph with 3.73 gears and 30" tires. I am getting the tuet11009 transmission which is the close ratio. They also said if I went with a 4.56 my first gear would basically be unusable.

Does anyone else have about the same experience with this? One calculator tells me one number and the other tells me a totally different number.

What is the final gear ratio of that trans?

[ryans69chevy]

The final drive gear ratio of the tuet11009 is .63. Anyone else have the transmission?

[kehstr]

want to do this swap eventually, subscribed to watch what you do

[Ruscal]

In my post above I gave some incorrect info.
My trans is the close ratio tuet11009. Axle is 4.11, tire diameter 28.3".
I was reading the tach wrong. It is really 2300 RPM @ 75 MPH. Engine is loud (Flow 40's) making 2300 sound like 2800. Viewing angle of tach is skewed, adding 500 RPM.
I just extended the exhaust out to the rear bumper. It was dumped in front of the axle. More civilized now, and less fumes.
Sorry about the error,
Russ

[sangell]

Originally Posted by Ruscal

In my post above I gave some incorrect info.
My trans is the close ratio tuet11009. Axle is 4.11, tire diameter 28.3".
I was reading the tach wrong. It is really 2300 RPM @ 75 MPH. Engine is loud (Flow 40's) making 2300 sound like 2800. Viewing angle of tach is skewed, adding 500 RPM.
I just extended the exhaust out to the rear bumper. It was dumped in front of the axle. More civilized now, and less fumes.
Sorry about the error,
Russ

Thank you for the updated info, real world experience is always helpful to those of us still in the build stages.

[ryans69chevy]

Thanks for the correction Russ. Those numbers prove that the speed calculator I'm using is correct. I typed in your info and it showed 2300 rpms at 74.79 mph.

I'm just really on the fence on which set of gears I want. Not sure if I should do 3.73's or 4.10's. 3.73's I'll be going 76 mph at 2000 rpms or else with the 4.10's I'll be at 70 mph. Any words of wisdom for me to help me decide?

Russ what kind of mileage are you getting on the highway with that? I'm assuming you still have the 350...

Thanks,
Ryan

[Tiger Joe]

I think the question would be what type of driving do you plan to do? Not sure if you answered that in this thread already.

if you are planning a lot of highway driving out of the truck, I would want my 2k rpm around 75. if you are just mainly doing back road crusing, but want OD for an option (like I did) then 2k at 70 is fine

[Ruscal]

Ryan,
Like Joe said, driving use and style could sway your choice. Also engine details such as camshaft, injection vs. carb. My stock carbureted 350 isn't real happy below 2000 RPM and would be worse with a big cam. Today we leave for a 2 day camping trip. I'll be towing a 3000 pound travel trailer. We'll see how her maiden voyage goes! We will be pulling one hill where my Jeep Wrangler had to use 1st gear. It has 4.56's with 33" tires.
I have not checked mileage yet. Speedo is off 7 mph with 21 tooth gear. I need another tooth or two, or one of the reducer gears.
The six speed is so fun that the mileage will suffer around town. The freeway mileage should be much better with the reduced R's though.
Russ

[mechanic350]

i bought the Hurst driveline conversion kit with a T56 Magnum and although we hit some hiccups during the install that we were able to recover from pretty quickly it wasn't a terrible install. i do agree with the earlier posts though. i love having gone from a th350 to the 6spd. and she will lug at 85-95mph in 6th but then again the PO got his gearing wrong and i have something like a 3.27 or 3.07 in mine. needless to say she has a lot of top end. but will cruise great in 5th at 65. barely even works the motor. Good luck if you choose to do it.

[NC_John]

Originally Posted by mechanic350

i bought the Hurst driveline conversion kit with a T56 Magnum and although we hit some hiccups during the install that we were able to recover from pretty quickly it wasn't a terrible install. i do agree with the earlier posts though. i love having gone from a th350 to the 6spd. and she will lug at 85-95mph in 6th but then again the PO got his gearing wrong and i have something like a 3.27 or 3.07 in mine. needless to say she has a lot of top end. but will cruise great in 5th at 65. barely even works the motor. Good luck if you choose to do it.

I had the original 3.07 rear when I initially did my 6-spd. The truck was geared for bonneville or Talladega. I about needed a push truck to get going in first (hi-perf clutch would chatter like hell)

[mechanic350]

Yeah totally feel you there. She may not like getting going but damn she will go. My buddy who helped me put in the trans and I went for a drive to feel put the new driveline and she will do 75 in 3rd 90ish in 4th and we slowed down at 115 in 5th with her still pulling to go faster. And that's with a mild 350. Smooth as all get out though. I have pictures of the swap out in my build thread.

[trkfrk]

I drove to Pomaona CA last weekend for the swap meet, a little over 500 miles. Truck ran great and averaged around 16 mpg. Here is a pic of my gauges while in 6th gear. we cruised mostly between 75-80mph.

[LongC'67]

Following this thread! I will eventually be pairing my 2009 ly6 and my tr6060 out of a Camaro in my 67. Having a VVT with a manual will pose its own set of challenges but its nice to see what people are doing as far as trans cross members, shifter location etc.

[Possmguts]

Originally Posted by mechanic350

Yeah totally feel you there. She may not like getting going but damn she will go. My buddy who helped me put in the trans and I went for a drive to feel put the new driveline and she will do 75 in 3rd 90ish in 4th and we slowed down at 115 in 5th with her still pulling to go faster. And that's with a mild 350. Smooth as all get out though. I have pictures of the swap out in my build thread.

Careful... I hear these thing start lifting off at 130ish lol.... I had a 70 Ventura way back and I remember the straight speedo read 120... I buried it and it bounced back to 20 and It felt like it weighed only about 3 ounces lol

[Possmguts]

Originally Posted by trkfrk

I drove to Pomaona CA last weekend for the swap meet, a little over 500 miles. Truck ran great and averaged around 16 mpg. Here is a pic of my gauges while in 6th gear. we cruised mostly between 75-80mph.

Thats great... cant wait to get-r-done... might be a while though
How does she ride at those speeds?