I'm sure this topic has been beaten to a bloody pulp and has long since decomposed, but I'm in the middle of class and dont really have the time to search the boards more thoroughly than I Have.

My 700R4 just went kaboom . . . . again . . . . and since we'll be pulling the thing anyway, I was looking into doing the manual swap.

My questions:
- What are the benefits of going with a T-56 over a T-5?
- Which company makes Best T-5 Replacement?
- Which company makes the best "Bang for the buck" T-5 replacement?

Im using a 10:1 355ci L98 making (rough guesstimate) 350hp in a 91 rs.

 

T-5 is weak. it may handle a Stock L98 ok for a while when rebuilt, but anything more i wouldnt run it.

the T-56 is great, but isnt a direct bolt in. gonna need a tranny crossmember and move the shifter like 2 inches back, and i think thats it. T56 is alot stronger. perfect for 450lbft or less. so with your plans T56 is way to go if you can find one for right price. they are a bit expensive. 1000-3000 (used to new) i believe richmond makes a bolt in T56 replacement for thirdgens but its 3000.

for that price, you can get a T5 (world class tranny, i think was from 88-92) and get the G-force tranny kit for 1000 and rebuild it with that. then it will handle whatever you can throw at it. just an idea http://www.g-forcetransmissions.com/tran_gt-5.asp

but i think some people have had luck with T5's (worldclass ones) with 350hp or so. i know there is another rebuilt kit that will handle some good power. somebody will chime in or do a search

 

Many 4th gens are putting 900hp thru the t-56 without problems! Downside, many rebuild shops dont have a clue how to rebuild them right, so people have failures and claim the tranny is weak. I have a friend that has rebuilt many t-56's and no problems even with loads of HP being put thru them. I will take a t-56 over a t-5 any day!!

 

Again, it depends on what you're gonna do with your car, drag race, SOLO, daily driver and so on. Swapping from automatic, the T5 is straightforward factory stuff, every bolt lining up--especially if you have a donor car--whereas the T56 requires an added level of fabrication or aftermarket parts that at least doubles the expense.
Strong T5's are expensive, too, except the TKOPerformance upgrade which handles 450 hp, so I would decide between a basic factory setup with an upgraded T5 for street and mild competition use or a T56 to handle whatever type of racing and power you'd ever like to handle in the future.
My Camaro is for fun and saving $1500-$2500 by going with the T5 made it a lot more fun--but I will never seriously race it. I have a T56 behind a 327 in a 1800 lb. street rod that will see open road racing next year--I'll use 6th.