I have an '89 GTA w/ 146,000 miles. Valve guides leak some. Engine has been well maintained. I haven't had the car long.

If I began putting induction/exhaust mods ont this motor, would that be smart? What about a cam/head combo? Anybody else out there have a high mileage L98 with mods...and how has it worked out? Would it be better to rebuild first, or swap out with something else?

 

I would start with all the free mods. Then do exhaust. There is close to .7 to 1 second off the 1/4 mile times trapped in the exhaust. If you have the money to spend, get a set of 1 3/4" SLP Headers (about $500 from Summit), a Random Technology catalytic converter ($210 from TPIS) and a Borla cat-back (about $500 from Summit or Jegs). If you don't have $1200+, the package of Edelbrock TES Headers ($300 from Jegs or Sumit), gutted cat or stock (free!!) and Hooker, Edelbrock, or Flowmaster cat-back ($250-$300 from Summit or Jegs) seems to work great. After doing that, its a good idea to do a few smaller things that you will need before you do heads and camming. Things like ignition parts, chip, AFPR, Air Foil all are a great help and don't cost over $200 for any of them. Good Luck!

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1987 Chevy Camaro IROC-Z
L98 TPI 350 (5.7L)
TH 700R-4 Transmission with 2.77:1 Rear End

Current Mods: Edelbrock TES 1 5/8" Headers, Hooker Aerochamber Cat-Back System, Performance Resource Chip with 160* Thermostat, Accel Ignition Components, K&N Filters, All Free Mods, Falken ZIEX Z-Rated Tires.

Best ET : 14.32 @ 97.7mph
(corrected for elevation)

 

I agree with Dan, do the free mods then exhaust.
Since I have a L98 with 110,000 miles and I just did a cam and head change this past spring I can say that it didn't hurt the engine. However, it did show me that the car is limited by the intake stock manifold (air). Also I need to get my injectors rebuilt or replaced, I would think you need this done if it hasn't been done.
If you are going to do the work yourself then by all means do the lower end (rings, pistons, bearings) else the top end is ok but think abuot getting it done in the near future.
Good luck!

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89 IROC 350 Auto
DUAL Exhaust
Edelbrock Performer Aluminum Heads
ZZ9 Cam
TPIS Level 5 Chip
14.01 @ 97.0mph with 2.77's gears

 

GOOD SOUND SOLID ADVICE FROME THESE GENTELMAN!!!
I have an L-98 w/ 107,000 and she hasn't leaked yet!! NO BULL!!
But just a little advice if u are on a tight budget and want 2 make that mamma scream?
Work from the back 2 the front!!
what i mean is that u want to stablize your drive train 2 prepare 4 the horsepower! do the rear end, get that stable then the tranny, that way u can work your way up as u drive and modify. i have seen so many mistakes made by misinformed people when they dump the horsepower in the engine they blow the trans or rear..
JUST MY 2 CENTS FROM ME WHO KNOWS!!



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92 F-BIRd FORMULA T-TOP (WHITEKNIGHT) 5.7L-98,700R4B&MSATURDAY NIGHT
SPECIALTRANS 2500STALL,54MM-AS&M TB-PORTPLENT,LARGETUBRUN,
UNDER PULLEYS K&NCOLD AIR KIT,160THERMO,ELDB HEADERS W/3 1/2 Y PIPE 2 RINO CAT 2 4INCH PIPE 2 FLOW,
MSDDIST,6AL,8MMWIRES.
2BLASTERCOIL.ACCELL PLUGS
CUSTOM FASTCHIP BY ED WRIGHT,AUBERN POSI W/ RICHMOND 3.73 AND SPLINES,TUBE FRAME CONNEC
PST KIT.1LE BRAKE KIT! MANY MORE MODS FORESEEN IN MY ERA!

 

What do you mean by "do the rearend" in reference to stabilizing the drive train?

 

sorry i mean lighter hubs ,new axel splines,ring gear& pinion,posi unit or limited slip (Aubern units iq) and driveshaft, also if u can afford it go with a 9-inch i will be in the future.

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92 F-BIRd FORMULA T-TOP (WHITEKNIGHT) 5.7L-98,700R4B&MSATURDAY NIGHT
SPECIALTRANS 2500STALL,54MM-AS&M TB-PORTPLENT,LARGETUBRUN,
UNDER PULLEYS K&NCOLD AIR KIT,160THERMO,ELDB HEADERS W/3 1/2 Y PIPE 2 RINO CAT 2 4INCH PIPE 2 FLOW,
MSDDIST,6AL,8MMWIRES.
2BLASTERCOIL.ACCELL PLUGS
CUSTOM FASTCHIP BY ED WRIGHT,AUBERN POSI W/ RICHMOND 3.73 AND SPLINES,TUBE FRAME CONNEC
PST KIT.1LE BRAKE KIT! MANY MORE MODS FORESEEN IN MY ERA!13.38ET @ 109.75MPH

[This message has been edited by ONEFORMULAOVERALL (edited November 08, 2000).]

[This message has been edited by ONEFORMULAOVERALL (edited November 08, 2000).]

 

If he's on a tight budget how the hell is he going to afford a $1800 dollar 9" rear for a high 14 sec. you could spend about the same and have relatively quick running L98, $300 cam, low buck headers(100-$300), $230 flow master exh. used vette converter$50, gear$ 150( installed yourself).if you have 3.42's i would wait ans instead bye a bigger THROTTLE BODY(52MM $280 ), and dont forget porting your intake sys. the best you can . i did this to my GTA when i had a 305. i went from like 15.2 to 14.0 on radials. i dont know what it ran with sportsman pros but i usually ran dead even with people who had high 13 sec. cars ...good luck bro

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87GTA looking for a super ram!!! 355, A4 ran high 12's with old school setup and radials, hoping for low 12's or better /91 TA daily driver LB9 A4 2.73,

 

really, lets not get carried away with blowing alot of cash on the car. it has 146000 and the motor is not running like new.
MY first order would be to find a junkyard 350 in a truck from the mid 90s with low miles below 40000 for 500 bux and drop it in but before you do so< do a few things to it. this engine will be a non roller because its from a truck. so you can buy a cam with 212-218 duration@50 with good lift, it will come with lifters. should be 100 from summit. get a set of cheap shorty headers and a y pipe for 150 and then drop the engine back in. later get a random bullet cat and a good muffler. the engine will work fine it is all the same and your intake will bolt right up. later you can get a chip if the car isnt up to your specs. then get a k and n and rig up some sort of simple cold air system and do all free mods and a good tune up. go to tire rack and get some good tires on the car and your done and while the engine is out also put on a gm2050 rpm stall from the 4.3 vortech pickup.i cant see how you would spend over 2000 doing all of this and you will have a solid 13.5 car with this setup which will get 23+ mpg and be reliable for under 2000 you beat stock lt1 cars. i did this same basic thing to a 350 tpi trans am but i used a roller cam with 224-230@50 and a better tranny which i had to have anyway, underdriv pulleys all free mods and a cold air and ran 112mph in the 1/4 with no traction

 

that would work too. if you get a 90's truck motor it should come with the added material(3 pedastals tapped for bolt's) in the lifter valley to install the retainer for the lifters so a factory roller cam could be installed. spend the money where you'll see the most gain. you'll be alot happier that way and have less regrets

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87GTA super-ramed 355, A4 ran high 12's with old school setup and radials, hoping for low 12's or better /91 TA daily driver LB9 A4 2.73,

 

I would have to agree with what was said in the past. I have had freinds do an engine first, then have their rear end blow out, then drive a little more and have their trans blow. My L98 has 132,000, and im replacing the rear around christmas time with 3.73's, then the trans with a shift kit, then the engine. from what ive heard adding a cam to an engine that already has that many miles on it will send it to an early grave.