am stuck on trying to select a transmission for my conversion. I have narrowed it down to 3 but I am not sure what is the best for what I need to get out of my car. (TH700R4, 4L60E, T56)

Right now my 1992 Camaro has a 305TBI, TH700R4(4L60), and 10-Bolt rear with 3.73 gears.

The car will be received an LS1 down the road so the transmission has to work well with that motor.

The problem I have right now is that at 90mph the car is running about 4200rpm. This is not acceptable for a daily driver. I am not sure of the gearing in the transmission right now.

What will give me the performance and a decent cruise rpm? I really need detailed information because this area is confusing me. Thanks!

 

3.73 gears, 26" tall tires @ 90mph you should be turning 3036 rpm. If what you say is true then you have smaller diameter tires, your tach is inaccurate (quite possible with an old factory tach) or you are not going into overdrive (4th gear). LS1 & Gen II transmissions are different & won't interchange without an adapter. 4L60E needs a controller to make it shift.

 

The car is hitting all gears. When a tranny is rebuilt can the gear ratio be changed?

If the OD gear in the 4L60 was a .70 and the 6th gear in the T56 was a .70, would that not be the same cruise ability?

 

if youre gonna throw in a ls1 you really only should consider the 4l60e or the t56. the 4l60e will work with the computer you need to run the ls1. it doesn't matter which trans you put in, if the last gear ratio is .7 to 1 it will cruse at the same rpms no matter if it's a t56 or an auto. i don't know cost differences betwwen the 2. unless you sitt in traffic everday like i do i would say t56 all the way. sometimes it takes me 10 minutes to go 15 miles and sometimes it takes an hour and a half. and when i'm in traffic i'm verry thankfull for not having to work that clutch every 5 seconds. but when i'm on an open stretch or racing someone i wish i had that t56. so do you have to worry about traffic, if not t56 for sure

 

In some cases it can be changed, very few do it, though.

T56 ratios are 1st 2.68, 2nd 1.78, 3rd 1.3, 4th 1.00, 5th .74, 6th .50