89firebird

So I was originally planning on keeping my car factory and numbers matching original. But after pulling the 305 for snapped exhaust manifold bolts, I decided to put in more power.

I'm putting in a new 383 GM Performance parts Engine, a FIRST Injection system, mostly new suspension and brakes, and some performance clutches in the T5.

So I know the weak points are the transmission, rear-end, and chassis twist.

I'm assuming on street tires, I should be ok. The old 305 roasted the tires, the new motor should as well. No big deal.

But if I get traction, and put the torque to the ground, what breaks first? In other words, where should I invest in next?

Thanks!

1987L69

I would say the T-5, goodbye 3rd gear! that is if you put a new clutch in it with the swap

MSgt Luttrell

The stock 700r4 was the first victim of the 430 HP/452 ft lb of torque 383 in my IROC Z, replacing it with a stage 3 700r4 built to handle 600 horse power and 500 ft lb of torque. This of course is putting my 10 bolt rearend on death row.

TTOP350

iTrader: (8)

Depends how you drive and what tire you use. My bet, your wallet.

UltRoadWarrior9

Very true... I use Continental DWS 295 35 18s in the rear and 275 35 18's in the front and they grip like a SOB!

I've heard stories of cracked windshields, especially with 3rd Gen Camaro's with T-TOPs. I'm doing a 383 build also, the first thing I installed was subframe connectors.

midias

Toss in a pro 5.0 shifter to help the T5, after that it depends what is in worse shape the transmission or the rear. For me it was the pinion gear in the rear end.

TTOP350

iTrader: (8)

Those stories are pretty much just that, stories, maybe a improper install on the glass but highly unlikely. But yes, subframes are a must

red rock

iTrader: (2)

What kind of HP numbers are you shooting for? A mild 383 isn't much different that a mild 350. If you plan on getting into the 400-450+ hp numbers, then the whole drive train is a crap shoot unless you build for it. In my opinion, the T5 is weaker than the weak 10 bolt. Higher HP numbers will require a T56 and at least a 12 bolt rear.

UltRoadWarrior9

Is the T5 weaker than a TH700? All else aside... Zero miles, no mods, etc.

I know the TH400 was a beast, was used in Hummers.

red rock

iTrader: (2)

All things being equal, I think the 700r4 is stronger because it absorbs the shock of standing starts. Revving the engine and dumping the clutch shocks the drive train hard. As for longevity, neither one will take constant abuse. You do lose more hp through a 700r4 vs. a T5, but then you have throw out bearings and clutches to replace. I think they are both good transmissions, and it all depends on if you like to shift a lot or not. When you get up in hp, that's when things tend to break.

89firebird

Well, I found out today. I hit 3rd gear pretty hard and the transmission now sounds like rocks in a dryer. And no 5th gear.

So back on the rack to see what happened.

Any suggestions on a replacement manual transmission that can comfortably handle 500HP and fit the car without a bunch of fabrication.

redneckjoe

I can say for a fact that when i put a mild built 350 in my t-top car, it cracked the factory glass all along the edges, everywhere. put subframe connectors in and it stopped cracking, creeking, and squeeking, lol.

midias

All depends on your budget and preference.

You can contact GForce and get a rebuilt T5 with a new case, gears etc for about $1800 and it is direct bolt in and according to gforce will take 600hp.

You can do a T56 swap that will cost around $2500 with a used trans. Although I would get it rebuilt stronger if you are at 500hp.

Or a TKO500 / 600 swap I think last time I priced them out they were $3800ish and will hold no problem.

All are fairly easy just require buying the right cluch, flywheel, bellhousing and cross member.

TTOP350

iTrader: (8)

Ah, the wallet broke 1st

89firebird

Thanks for the suggestions.

I went ahead and ordered a T56 Super Magnum Transmission with all the installation items. Also a Pro 5.0 shifter to top it off.

While I was at it, I ordered a Moser 12 Bolt with an Eaton 33 Spline Posi.

To add to the frame strength, I ordered some Alston SFC's.

Any other suggestions to make this a solid vehicle?

Thanks!

red rock

iTrader: (2)

These are money pits. But fun.

MoJoe

iTrader: (5)

The post right after yours (#15) suggests he at least had a thick wallet. It may be broke now.

five7kid

iTrader: (14)

I'm a little late to the party, but I would put subframe connectors in a V6 car.

I have a Moser 12-bolt in mine, with 1350 u-joints. I would say that would be next on my list - 3" DOM steel driveshaft with 1350 yokes & u-joints.

TURBOTOMMY

I broke 2 rear end's,then 1 T5,,fixed it and traded it for a 4x4 Tacoma,,then blew the Tacoma engine to kingdom come....Tacoma's don't like No2

red rock

iTrader: (2)

That's why I don't like power adder's. Most people use the stock motor and add NOS. All you can expect is an explosion.. When you build the bottom end to accept huge power, then supercharging, turbo's, and NOS can be used with some confidence.

TURBOTOMMY

Awww come on now,,power adders are fun..Thats the only engine ive ever wasted with No2..Seen alotta guys running the stuff with stock bottom ends,,they can easily handle a100shot..Its just a chemical form of supercharging,,alittle forethought and planning and you wont have any problems with it...No it isn't,,i wasted a riding lawn mower engine with it also...

TURBOTOMMY

A guy in our shop has an old beater pos v6 mustang 94 I think (cheap work car) he sprays the guts out of it with a 90shot every other day going to lunch.....

red rock

iTrader: (2)

I think you missed my point. I agree, you can use NOS in a stock engine, but they are not made with high quality parts and sooner or later, something will let go. I raced against a guy that run NOS in his stock 500 free air vintage snowmobile for three years and then he blew it so bad even the hood needed replacing. Lol

TURBOTOMMY

Thumbs up

midias

Is this the motor you are running?

http://www.gmperformancemotor.com/parts/19332532.html

JoeMonte

So, if shifted gently, as in, not slammed as fast as possible, third gear should last at least a little while, correct?

MoJoe

iTrader: (5)

"Banging gears" and the resultant shock load certainly does not help in longevity.

However, rolling into the throttle producing more power through the trans than it can handle will eventually blow it, too. The power causes the gears to leverage themselves apart, and the case will not be able to keep the parts in place, and sooner than later... Boom!

GM never put a T5 behind a 350 because it wasn't strong enough for them to warrantee 100,000+ cars. But, if you don't beat on it, the T5 could last for a long while behind a stock 350 TPI. More power and more abuse shortens the lifespan.