Need More Gears...

[78 Bird]

Alright so heres a pretty common issue. I have the stock 4 speed in my 78 firebird with a 3.73 rear end hooked up to a chevy 350 putting out 375hp and 400ft/lbs. now my budget isnt huge but ill see what i can do, i have access to a junk yard and can get any part from there for free! now ive heard a few different options, the tremec (expensive) the t5 (weak) and more recently the t56 which ive been looking at more closely seeing as there are tons of them out in the junk yard. now id like to know everything needed for my swap if i do end up going with the t56 i know it needs a hydrolic clutch but im not sure how involved that is and im not sure what other things will need to change in order for it to work. also if there were any other cheap options to get a 5 or 6 speed in my car with little fabrications or modifications that would be great! im only 17 and working on a semi tight budget after purchasing my engine then installing it myself. lastly what ill be using the car for, i will be taking it on the highways a lot to my cottage, and to shows (i dont believe in trailers :P ) and i will like to take it to the track a few times to see what it can do but it is by no means a drag car. Mostly just street driving and just showing my buddys at school what she can do ;) any help would be great! Thanks, Ray

[protouringorprostreet]

Throw a gear vendor on your 4 speed

[78 Bird]

Throw a gear vendor on your 4 speed

would that be similar to the 80s corvette set up with the 4+3 system? Being a die hard manual transmission guy throwing an overdrive on was not my top option but the more i look at it im starting to like it. basically it would just get me a lower cruising speed but keep the same feeling of the 4 speed, seeing as i can get a t56 for free from the junk yard, what is everything needed for that type of swap if i decide to go with that? i just want to play out my options to get the best bang for my buck. i free 6 spd tranny definitely saves some $

[TheJDMan]

My only issue with a GV over/under drive is the price. $2895 for the GV is the same as a new T56 Magnum. And both require the drive shaft shortened. I have been waiting for the Keisler SS700 to start shipping before I make a move to an OD.

[T_Raven]

You can put either a LT1 or LS1 t56 behind a chevy engine. If you were to use the LT1 version you can use the LT1 bellhousing and hydraulics. You need an adapter for the master cylinder. It bolts behind the brake master and holds the clutch master. I don't know of any option to use a manual clutch linkage with the LT1 version.

With the LS1 version you can use a 4 speed bellhousing and manual clutch, but you need an adapter plate for the bellhousing and an extended pilot bushing. If you used a hydraulic clutch then you'd need the same adapter for the master. I don't think you can use the LS1 bellhousing on a small block but I might be wrong. You'll also need a 26 spline clutch.

[78 Bird]

Alright, between the two do you know which one would be the cheapest?

[78 Bird]

You can put either a LT1 or LS1 t56 behind a chevy engine. If you were to use the LT1 version you can use the LT1 bellhousing and hydraulics. You need an adapter for the master cylinder. It bolts behind the brake master and holds the clutch master. I don't know of any option to use a manual clutch linkage with the LT1 version.

With the LS1 version you can use a 4 speed bellhousing and manual clutch, but you need an adapter plate for the bellhousing and an extended pilot bushing. If you used a hydraulic clutch then you'd need the same adapter for the master. I don't think you can use the LS1 bellhousing on a small block but I might be wrong. You'll also need a 26 spline clutch.

Btw I can most likely get either of these transmissions and hook ups for free off donor cars at the junk yard

[T_Raven]

From what I've seen people seem to want around the same prices for both types. Usually $1200-$1500 for a transmission alone, and $1500-$1800 for a full swap with bellhousing, clutch, hydraulics and cross member for 4th gen guys looking to swap from an auto.

Some of the LT1 t56s have a 3.36:1 1st gear, rather than the LS1's 2.66:1 1st gear, which also causes it to have a lower torque rating. The higher numerically a gear ratio is, the bigger difference in gear sizes, which means less tooth contact, so less strength. Just a FYI for those who didn't know why they were rated lower. I believe the ones with the 3.36 1st also have a .62 overdrive rather than .5 like the ones with the 2.66 1st. You probably won't be able to use a .5 6th gear with a carburetor anyway.

If I could get t56s for free my shop would be full lol. The only benefits I can think of to the LT1 trans would be you can use the LT1 bellhousing, and the lower 1st would be good for an engine that doesn't make a lot of torque.

The downside to the LS1 trans is that you need a bellhousing adapter to use your 4 spd bellhousing and an extended pilot bushing. But that would allow you to keep the manual clutch. Mcleod makes an adapter PN: 8-207. I bought that one to put a t56 into my 67 Firebird, I think it was around $250, but I've since decided to use a quicktime bellhousing which will mount a t56 to a Pontiac engine without an adapter.

If you ever plan to swap to an LS engine already having the right t56 would be beneficial.

[78 Bird]

From what I've seen people seem to want around the same prices for both types. Usually $1200-$1500 for a transmission alone, and $1500-$1800 for a full swap with bellhousing, clutch, hydraulics and cross member for 4th gen guys looking to swap from an auto.

Some of the LT1 t56s have a 3.36:1 1st gear, rather than the LS1's 2.66:1 1st gear, which also causes it to have a lower torque rating. The higher numerically a gear ratio is, the bigger difference in gear sizes, which means less tooth contact, so less strength. Just a FYI for those who didn't know why they were rated lower. I believe the ones with the 3.36 1st also have a .62 overdrive rather than .5 like the ones with the 2.66 1st. You probably won't be able to use a .5 6th gear with a carburetor anyway.

If I could get t56s for free my shop would be full lol. The only benefits I can think of to the LT1 trans would be you can use the LT1 bellhousing, and the lower 1st would be good for an engine that doesn't make a lot of torque.

The downside to the LS1 trans is that you need a bellhousing adapter to use your 4 spd bellhousing and an extended pilot bushing. But that would allow you to keep the manual clutch. Mcleod makes an adapter PN: 8-207. I bought that one to put a t56 into my 67 Firebird, I think it was around $250, but I've since decided to use a quicktime bellhousing which will mount a t56 to a Pontiac engine without an adapter.

If you ever plan to swap to an LS engine already having the right t56 would be beneficial.

Thanks for all the info! and yes I am very thankful for the fact that i have a junkyard to go to and get free parts, from your info it looks like i am going to go with the ls1 because my car has plenty of torque and power and if it will be stronger thats always a plus. I will also probably end up converting to a hydrolic clutch seeing as i will have a donor car with all of the hydrolic set up and if i can take it out of that car and insert it into my firebird instead of the manual clutch that would be great. there has to be about 20 4th gens total in the junkyard, about 9 of them are manual. so if i can get the tranny for free and the hydrolic set up, then im just left with installing it and shortening the drive shaft correct? and also what about the shifter location? will that line up in the stock hole in the console?

[T_Raven]

If you don't know what adapter you need for the master, here's one on speed tech's website. There are quite a few people who sell them. It's not a hard thing to make if you want to save a few bucks. I don't remember the angle of the bend in it but there are plans out there that show the measurements.

http://www.speedtechperformance.com/...rod/prd212.htm

To use your 4 spd bellhousing you need this adapter. This is mine



I don't know if you can use that with a LS1 style throw out bearing. It might only work with a manual clutch. If you want to convert to hydraulic you can either use the 4 spd bell housing and some kind of universal hydraulics, or you could use a bell housing designed specifically to put the LS1 t56 behind a Gen I small block. The Quicktime bell housings seem to be nice because they are one piece, as apposed to the Mcleod modular bell housing, and Quicktime claims you don't need an extended pilot bushing.

As far as I know, to put an LS1 t56 behind a Gen I, you will need an extended PB with any bell housing option other than the Quicktime bell housing. Mcleod has one listed but I don't know if it's the right one.

http://www.mcleodracing.com/products/Pilot+Bushings.mcl

I hope all that helps. Figure out what bell housing you're going to use, get the master adapter, extended PB if necessary, 26 spline clutch, then you just need a cross member and drive shaft. Speed Tech has a nice cross member, or you could make or modify one to save some cash.

You can get by with a stock shifter but if you are ever in the market for an after market one, there are a few different ones. One that's less known about is the MGW because it's not on their website. There are threads about them on ls1tech.com. I've got one in my 01 TA and like it. I had to call to order it.

Edit: just saw you asked about shifter location. It'll be about 3 inches further back than stock. I'm not sure what options there are to move it foreward. I've never planned on having a stock console so I've never looked into that part.

[78 Bird]

If you don't know what adapter you need for the master, here's one on speed tech's website. There are quite a few people who sell them. It's not a hard thing to make if you want to save a few bucks. I don't remember the angle of the bend in it but there are plans out there that show the measurements.

http://www.speedtechperformance.com/...rod/prd212.htm

To use your 4 spd bellhousing you need this adapter. This is mine



I don't know if you can use that with a LS1 style throw out bearing. It might only work with a manual clutch. If you want to convert to hydraulic you can either use the 4 spd bell housing and some kind of universal hydraulics, or you could use a bell housing designed specifically to put the LS1 t56 behind a Gen I small block. The Quicktime bell housings seem to be nice because they are one piece, as apposed to the Mcleod modular bell housing, and Quicktime claims you don't need an extended pilot bushing.

As far as I know, to put an LS1 t56 behind a Gen I, you will need an extended PB with any bell housing option other than the Quicktime bell housing. Mcleod has one listed but I don't know if it's the right one.

http://www.mcleodracing.com/products/Pilot+Bushings.mcl

I hope all that helps. Figure out what bell housing you're going to use, get the master adapter, extended PB if necessary, 26 spline clutch, then you just need a cross member and drive shaft. Speed Tech has a nice cross member, or you could make or modify one to save some cash.

You can get by with a stock shifter but if you are ever in the market for an after market one, there are a few different ones. One that's less known about is the MGW because it's not on their website. There are threads about them on ls1tech.com. I've got one in my 01 TA and like it. I had to call to order it.

Edit: just saw you asked about shifter location. It'll be about 3 inches further back than stock. I'm not sure what options there are to move it foreward. I've never planned on having a stock console so I've never looked into that part.

Thank you, you have been a huge help! I'll start looking for more info on that shifter position but other than that it seems very doable. also i was thinking with a .5 6th gear itd be a great time to throw on the 4.56 posi i have at the shop, at least you know it wont get annoying on the highway ;)