prokilllsx

So in my garage sits a charcoal gray 89 Trans am GTA. My Dad owned it from 90 until around 97 and put 179k on it. It has the original 350 still in it and has had a reported miss fpr the last 70k and three or four owners. I'm guessing it's an injector or two but not real concerned as I plan to seriously upgrade the drivetrain! I am so glad for the car to be back in the family and have big plans for it.

With cost being the main factor... Should I rebuild the L98, possibly stroke it, go with a better intake, heads and a cam and get a stouter 700R4 or should I go LT1 or LSx??? I want low, low 12's to mid 11's and plan on keeping the car near stock weight.

I hear LT or LS conversions can be very costly and we all know it's decent money to modify one. This car ran a best of 14.35 at 95 back when dad had it with just a few common bolt-ons and Eagle GS-C's.

It is very appealing to me to keep the L98 for ease of keeping my AC, cruise and 700R4. Whether or not anyone makes a 700 that can take what I have planned I am unsure. Stock gears (3.23) would likely remain. It would be nice too if I could stick with the Borg-Warner 9 bolt out back. Do you think it is strong enough??

Any wisdom would be nice to here. Thank you.

jdmotox333

idk about that rear but i think be a good start just searching for built small blocks cause for twelve you would only need maybe 400hp so im sure you could easily find a decent 350 sbc somewhere

LT/LS Guy

383 TPI stroker kit with H/C/I and nitrous with a stout tranny & rear should get you in the 11's.

GTOSE

iTrader: (1)

LSX, you'll end up going with one eventually.

prokilllsx

No Nitrous. Whatever I decide will be configured for a future supercharger. I do like the idea of the LSX but don't have an extra couple or few grand for conversion on top of the engine and mods. My past includes 2 LS1's and I loved 'em both. I'm leaning towards keeping the L98 build with H/C/I and future supercharger. How much will it cost to take the stroke the L98. Anybody?

Any thoughts of how strong the 9 bolt is?

GTOSE

iTrader: (1)

Better than a 10 bolt.

There are cars in the 10's on the stock 9 bolt.

F-Body Lover

stay with the L98 stroke it 383 and AFR 220cc heads and solid roller cam a built TH350 and you are in 10s

ScreaminRedZ

iTrader: (3)

I've always been a fan of a fast 3rd gen with an L98 still in it. The LSX swaps have gotten popular because the kits out there now make it easy to swap, and you can't really beat the performance. That being said, I've always wanted to build up a TPI powered 3rd gen!

Redfire 03

There are cars in the 10's on the stock 10-bolt as well.

jdmotox333

lmao funny guy here^^^^^^

ZONES89RS

iTrader: (25)

It is like this, i went with a carbed LS engine to save money, it end up being pretty damn cheap, a 700$ long block, a 200$ used cam, some springs and pushrods with the carbed intake, 1500$ later, i have a car that runs mid 7s in the 1/8th all motor at 95 MPH, and next outing it should go low 7s with a hard launch, so, with stock heads and just a cam and carb conversion, i have a 11 second car, not to mention the 150 shot that is going on it, and once i get some porter LS6 heads, it will be close to 10s all motor, if it doeswnt actually just go high 10s, that is the goal and if it broke, i am not out a set of heads, a built short block, blah blah, wish i had went with the 6.0 WAAAYYY sooner.

GTOSE

iTrader: (1)

That's like dividing by zero.

Pretty unpredictable and potentially dangerous.

But seriously, 10 bolts are turds. 9 bolts are much better in comparison.

Mike Morris

iTrader: (55)

383,AFR heads,Super ram intake,custom ground cam,1.6 rockers upgraded stud size,full exhaust,under drive pulleys,SLP cold air,373 or close in a late model 10 bolt(with girdle,welded axles tubes,a solid sleeve,good carrier)-your older 10 bolt is weaker-get one from a 90 and up Fbody V8),MSD 6A with a good coil. 24lbers would work well. Sounds like one of your injectors is a goner(common with those Rochester ones). Get the skinny Bosch light blue ones from a 97-98 Taurus 4 banger(same as the FMS ones) and will plug in. Get a custom prom for your set up so it runs and then have it dyno tuned. You can get a 700R4 to survive at those power levels so you still have OD. Get a stock Ls1 drive shaft too.
Easy 11 second car on drag radials and can be driven anywhere

Redfire 03

Point is, there are several cars that have made it in the 10's on the stock 10-bolt. That was the point I was trying to make and nothing more.

87silverbullet

iTrader: (11)

I built a 92 z28 for my cousin and we kept it efi. Here's the list:

Stock 122,000 bottom end
AFR TPIS 187cc cnc'd heads
TPIS zz409 cam
Holley Stealth Ram
Holley 24lb injectors
Hooker LT's
3.42 gears
Coan Racing built 700r4
Coan racing 28-3000 converter
Stock 48mm tb (52mm made no more power on the dyno)
TPIS stage 5 chip
Mufflex 4in exhaust

11.83@115 was the end result. It is street driven and runs like a bat out of hell on the hill. I ran him in my c6 vette and we were door to door all the way from 50-145 mph then he started to pull away from me.

Here are some pics on the dyno.

$750 L98

iTrader: (7)

Since you and I have the same year, I will give you my personal advice. If you CANNOT wire a LSx harness yourself, or DO NOT know some one who can, do not do an engine swap. I cannot tell you how detrimental that is.

Now, I LOVED my L98, but I had just rebuilt mine and it blew up 3 months later, so I went all out one last time hoping to get all the bugs out (as my trans died at the same time). I went with a LQ8 build, done for me by a shop. Consequently it was a catastrophic failure do to poor workmanship and inept electrical work.

My plan, were I you, would be to rebuild what you have. A stealth rammed 383 stroker TPI is nothing to sneeze at. Especially if you add a cam, even on stock heads. Mine blasted the tires off at anything under 50mph and made 1st/2nd useless.

If you do plan to swap in a LS series motor at some point, definitely do the wiring yourself, if nothing else. You will also need to decide if you want AC, in Texas for me, it's a must. That will require notching the K-member and grafting in the 4th gen system.

You will also need to either use a early C5 regulated fuel rail, or get a 4th gen tank (or use the newer C5 regulated fuel filter). If you use a 4th gen tank, you will need to either modify the in tank sending unit, or modify you stock fuel gauge (replace/solder in new resistors to match the 4th gen sending unit). I did this on my bird rather than mess with the OEM stuff in the tank, seems safer to me. If you go LSx I can provide a tutorial on modifying your fuel gauge.

The other issue with LS swaps will be exhaust, it's hard to find quality fitting parts, considering that there is no standard motor mount or K member. I have heard issues using hawks headers with automatics, the 1 5/8th units supposedly won't fit, but the 1 3/4 will. You can also use Edelbrock Shorty headers, or stock manifolds. BRP also makes a nice looking set of mids, though I have yet to try them. (I will be running them after I re-assemble my top end).


Cliff notes: Long story short, with what you have, you can rebuild a very fast TPI set up for cheap. You could also build a nice carb'd LS swap. However since you are a 1989 if you have to pass emissions, rule out going carb'd.

Doing a EFI LS swap into a 3rd gen is not cheap in my experience, and you MUST pay great attention to detail, or pay BIG bucks to have some one like Hawks do it.

Also, the 9 bolt is a great diff, and you can still get parts. I'll have to find that site again...

ZONES89RS

iTrader: (25)

I am using a 89, i pass emissions(wink wink) and i have no issues, LOL.

ProStreet_632

LSX based if you can afford to do so

1nasty86

iTrader: (63)

love the lsx platform. thers soo much stuff for them. and new stuff is comming out every day. my vote gets lsx!!

prokilllsx

The car has the Borg Warner 9 bolt in it.