tailwindxr7

I plan on buying an L98 3rd gen, probably an IROC, sometime in the later future, but we all know the 350s only came with automatics.

How hard and expensive (probably have a shop do it, don't know jack about trannies) is it to swap in a durable five/six-speed? Are there any transmissions out there that'll just bolt right in? I'd prefer a six-speed, but it's not really imperative.

I'm also planning on making a 383 stroker out of the 350, so the tranny will have to be strong enough to hold up to 400+ hp and torque...can anyone help me out?

guywidiroc

I would suggest buying a 5spd tpi, then doing a 6 spd 350 swap. Both are easy to do, and the $$$ depends on how exotic your motor tastes are.

want.to.know

What ever you do not but a WC T-5 305ci behind a 350ci.
thats why it was never strong enough, thats why they all came in autos. go with the LT1 t-56 trans, something that won't burn out.

http://www.skulte.com/T56.html

here is a site i've been looking at. the t-56 israted at 450ft lbs of torque, tq is the main thing to look at.

if you really want a 5 speed go with a tremec.

http://www.fortesparts.com/ rated at 500ft. plus.

i plan on doing the same to my 455 buick, i'm just a cruiser so i'm not too worried about tq. i figure 450ft is good enough. some even reach 500ft. with no probs. the t-56 can handle more than it's rated. it's going to be nice cruising w/ a t-56 on the highway at 2000 rpm in my 72 lark.
Good luck to you.
And i know i'm going to get crap about my buick,
from some of you. all i got to say is bow down!!!


later!!!! Albert R.

tailwindxr7

Yeah, I know how weak the T5 is. I wouldn't use it.

I don't know if a T56 can handle a 383's torque, but if it can, I may go that route. The Tremec is great, but a six-speed would help with the mileage.

But to the other guy, why would I buy a five-speed 305 car if I'm just going to end up swapping the tranny either way? The 350 in another car would actually serve a purpose to me, while the 305 would just need to be trashed and replaced...it seems like a waste of time and money.

Jim85IROC

The T5 will hold up if you don't beat it like a redheaded stepchild. There are guys that have had the T5 behind 400+ horsepower without any problems. One good thing about the T5 swap is that it's about the easiest swap you can do. I decided to do the T5 swap because the T56 swap is just too expensive in the IROC. In addition to needing the expensive T56 clutch, in the Camaro you also need a $300 box to keep your stock mechanical speedo. The T5 swap cost me very little, the clutch was cheap, and I could maintain all stock equipment. Down the road I'm planning on the T56 that want.to.know linked to. That T56 will allow me to keep my stock speedo, stock T5 shifter (although I'll go to the pro 5.0), and most importantly, stock clutch setup that I prefer over the ***-backwards 4th gen style.

tailwindxr7

Are you talking about the stock T5 or the Tremec T5?

There's no way the stock one will hold up to 400+ torque and HP...

guywidiroc

Tailwind....have you ever swapped a manual trans in a car with an auto??? Doubtful. This is a hell of a hassle even for those who are mechanically inclined. But if you think its easier.....go buy an auto, and try it. I just suggested the easiest route. Swapping a 350 in place of a 305 is easy, and were you gonna leave the stock L98 in?

aklim

If you don't know jack about trannys, why are you doing it? What are you trying to achieve? I mean, what are you trying to get the car to do that it can't already do.

My stock GM rebuilt tranny held up for 6 months behind my LPE 383 with me babying it. My Rossler built trans lasted for 3.5 years with me beating on it. You can build them up for durability. They are better in the quarter mile in terms of consistancy. Talk to www.rosslertrans.com for a complete build up. You can specify the RPM you want the shift at and whether you want it to shift hard always (heard it is better on the clutch pack) or hard at WOT and soft at anything else.

Note, autos suck on the autocross tracks. So, if you are going to do a lot of autocrossing and are trying to be competitive, go bite the bullet on the T5 swap. In this case, make sure it is built up good. Unless you are going to do a lot of cross country driving, the T56 will probably not help much. Just stick with the T5. Cheaper and easier.

i RoC U

i have a t-56 in my 383 stroked iroc and its never given me any touble despite putting over 500 ft/lbs through it. its the clutch that always blows with a t-56, not the tranny. there are guys running low 10's with a stock t-56. it will be better for highway driving, and it will allow you to run a lower gear ratio and still maintian good gas mileage. ive got 4.11's in my ride and with the 6-speed, it keeps the rpms nice and low on the highway.

if youre going to be serious into dragging, then i would go with an auto all the way, though. like aklim said, if ur more of an autocross guy, or you plan on highway/daily driving then i would go with the t56.


just my $.02

super83Z

The T-56 is an easy swap. I did it in a day from an auto car. As long as you have a sense of what is going on in a car it is easy

tailwindxr7

How come some of you pick up on the small "I don't know jack about trannies" part of the post, but you somehow miss the "I'll let a shop do it" and "I want to rebuilt the L98 into a 383" parts?

Read the whole message, most of your questions are answered in it, and it was already there in the first place.

From what's been said, the T56, although probably harder to swap than the Tremec T5, is a better choice for me. I want the six-speeds for the aforementioned gear ratios and highway mileage. If it can hold up to the power, I can always upgrade to a heavy-duty clutch to keep that from getting fried, too. Not a huge problem there.

Why are some of you talking about autos, too? The topic had absolutely nothing to do with keeping one...

Also, in case you were wondering, the car will be something more like a badass road beast of a toy car than anything. I'm planning on the 383 for around 400-450hp and torque, a suspension setup that can handle the power and keep the car handling/turning well, a stiffened chassis, some good brakes, and a manual for enjoyability. It won't be all power, more of an all-around type of car, like a Z06. Even if I do drag the car (which I probably will), I'll still want the manual. Sure, an auto may be more consistent, but it's still boring as hell and still lacks the skill it takes to drive a stick well in my opinion. So you can imagine what it looks like, I plan on a shiny black IROC-look, maybe a 4th gen black or gray Firebird interior, and t-tops (still want them, even with the power.)

super83Z

Regardless of which tranny you go with I would suggest www.spohn.net for the crossmember they are of awesome quality.

i RoC U

i 2nd that. i have the spohn tranny crossmember/adjustable torque arm package and its second to none.

Jim85IROC

It depends how you drive it. Chuck Everly had a T5 behind a 420hp 383 and never had a problem. A few guys on thirdgen.org had their T5 survive for a while behind their 12 second rides, even with speedshifting. I've also seen them get lunched behind stock TBI 305s. It's all about luck of the draw, but you can help sway your luck by driving it smartly.

aklim

Reason I mentioned it is that you need to investigate what tranny
you are going to use, what are the advailable gear ratios, rear end ratio, where the cam makes the power (I think you can change the gear ratio in the T5) and things like that before the swap is done. With the 700R4, you need to know what stall based on the cam, rear end. It does not allow ratio changes.

In my case, with the A4, I would want less wheel spin in the first gear if it was going to be a street machine and not so much a daily driver so I would go with the 200R4 for the lower first gear. That's why I say that application is the most important rather than the other intangibles you mentioned. For that reason, I should have said "you need to study up what each facet of the thing is good for. They all have their goods and bads.