Hey,

I really want to start building up my 88 TPI. My first newbie question is when looking at parts for a "350" how do I tell if they will fit my engine specifically? its in an 88 GTA. I wan tto add headers, heads, some sort of cam (need to understand the different types still), and probably just a high flow backpipe and muffler. Any suggestions on these items would be great. I dont need a race car but definetly want to make more power. Brands would be great.

Thanks alot

 

While there were countless changes over the years, the meat and potatoes of a 350 didn't change much from the original 350 until the introduction of the LT1. Nowadays, pretty much 99% of our Chevy V8s are listed as 350, LT-x, and LS-x. If you see a gasket set for a Chevy 350, it'll fit YOUR 350.

LOL- Betcha we could debate and discuss THAT statement for the rest of time!!!

.....but here's what you need:

As for headers, ANY small block chevy headers will fit the engine, but most won't fit into our Thirdgen cars. While some generic headers will fit, my opinion would be a shorty header designed to fit an 82-92 F-body small block engine. "shorty" means that the four primary tubes aren't equal lengths. Priority was given to "fit" not function. As luck would have it, our TPI intakes don't really need a "Long" style header. SLP, Hooker, and edelbrock all make headers designed to fit. I'd bet over 50% of us are running SLP or Hooker. Do a search.

As for catback systems, again, it's basically just pipes that are prebent to fit our cars. Shoot, who DOESN'T make a catback?!?! SLP, Hooker, Flowmaster, Dynomax, Borla, Magnaflow, Edelbrock, Mufflex, etc. etc. etc. etc.

with headers and a catback, you'll want a high flow cat too. I got mine on Ebay for $50 bucks. It's a magnaflow. BTW, check your RPO codes. If you have G92, then you'll need 2 cats. hehe, or you could look under the car and check!

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Ok, that advice is pretty sound I think, and regardless of what else you do, exhaust is one of the first mods/upgrades that most people do, and one of the most needed.

As for heads and cam? Well, now you've opened pandora's box. As stated earlier, pretty much any 350 head will work, and pretty much any cam will work. Being an 88 model, your 350 has hydraulic roller lifters, so you'll need a hydraulic roller cam, but pretty much anything will fit. That being said, just because it'll fit properly and bolt on, it doesn't mean it will work right.

-Whew, where to begin. Budget and goals. Without these, we could debate the topic for years and years. Baically, think airflow. You want to flow more air, which means a larger port on the new heads. You'll need a cam which will allow more air to flow to the head. These two matching is more important than simply "bigger is better". -but if the intake can't flow a lot air, which the TPI intake doesn't, then a big cam with big heads will be wasted. So you get a high flow intake, but then you need to add more fuel to burn with the air. So you get bigger injectors, but the fuel pump can't handle it. So you get a bigger pump, but the computer now isn't tuned. See where I'm going?

There have been countless books written on this subject, and thousands and thousands of threads posted on countless message boards discussing this topic, and still, a lot is up for debate. Look at your budget and goals. When you know what you want and what you can spend, we can help you get there. In the meantime, read read read read read read and read some more!!!!

 

Thanks you so much for the reply. That puts things into perspective really good. I geuss headers are the next thing. I have a Borla exhaust so Im wondering how much power this will gain.

Thanks

 

OK, here's my recommendation for what I would do, having done them myself.

Assuming the car is tuned up and running well......

Exhaust is a great place to start. Headers and catback with a high flow cat in between.

Now for a little while, forget the engine. Focus on that automatic. I had performance rebuild with a 2500 torque converter installed. This was the single biggest performance mod that I've done.

....that, and look at the rear end gear. Having a GTA, you "probably" have a 7.625" Borg Warner rear axle, which we on TGO call a "9 bolt" for it's 9 bolts holding on the rear cover. The ring gear is 7.625" inches as opposed the the standard Thirdgen rear that has a 7.5" ring gear, and "10 bolts". The "9 bolt" is substantially stronger, but don't confuse the "9 bolt" with the legendary Ford "9 Inch" rear. Two totally different animals. Anyhow, back to the point. IF you DO have the 9 bolt, it'll handle a deeper (higher numerically) gear without too much worry about breakage. Your RPO codes should reveal the gear ratio, but better than that, jack up the rear, count the bolts, and if ya got 9, one of them will have a tag with the gear ratio number. I think the 350 cars were optioned with 2.77 or 3.08 ratios. I'm not 100% on that, but either way, you can go a good bit deeper. I swapped in a 3.27 gear, and a lot of people swap in 3.45 gears. More than that and (in my opinion) daily driveability becomes an issue. I found the my entire rear axle with 3.27 gears for $200. Took an afternoon to swap.

- If I had to mod a bone stock 350/L98 thirdgen, first would be exhaust, second would be trans and rear gear. It'll be like driving a new car.

I've also swapped in a ZZ4 cam, and it certainly added some power, but nothing like that new automatic trans and torque converter!!!

 

Thanks for the help. Is there a cam that is above most others? Im just wondering what are some of the better models for more power ut street driving.

Thanks

 

Well again, it goes back to budget and goals. I chose the ZZ4 cam. It's got 208-221 degrees of duration at .050, and lift is .474-.510. It's computer friendly, meaning you don't HAVE to retune the computer, and it not too much cam for the stock heads. You can also get it fairly cheap. You'll need new valve springs, and you'll probably want to get screw in studs in the heads as opposed to press in factory studs.

.....I won't say there's no other's out there, but after doing MY research, I felt it was the best choice given I wasn't gonna change the heads, and I wasn't gonna remove the TPI intake.

You've mentioned changing heads. If you're gonna do that, the ZZ4 cam is probably gonna be a little small. That and with new, better (bigger) heads, sooooo many other things need to be changed and upgraded. The project can start to spiral real fast. Not that I'm trying to change your mind, just saying it's not as simple as asking the simple quesiton: "What heads and cam do I get".

 

Sorry to hi-jack the thread, but where exactly on the RPO codes would it say what gears the car has? I've ran the codes for my '86 T/A, with the exception of the 3 RPO codes I've yet to be able to find (WS1, WS8, YT9), the only mention of my rear end is "Positraction, limited slip". Thanks for any help.

 

POSI OR LIMITED SLIP ARE THE SAME AS FAR AS THE AXEL RATIO HERE IS A LIST OF THE RPO CODES FOR 1986


AAA 4-WAY MANUAL SEAT ADJUSTER AK1 COLORED KEYED SEATBELTS AM9 SEAT, RR, SPLIT, BACK, FLDG AS5 SEAT, FRT BKT, DELUXE RECARO SEATS AU3 LOCK CONTROL, SIDE DR, ELEC A31 WINDOW, POWER OPERATED, SIDE BV3 ORNAMENTATION, INTR, I/P, BLACK B20 ORNAMENTATION, INTR, LUXURY B34 CARPETED FRONT FLOOR MATS B35 CARPETED REAR FLOOR MATS B67 CONTAINER, RADI0 CASSETTE TAPES B84 ORNAMENTATION, EXTR MLDG, B0DY SIDE B87 ORNAMENTATION, EXTR EMBLEM FENDER---DELETE B97 ORNAMENTATION, EXTR MLDG, LOWER ACCENT CC1 ROOF HATCH, REMOVABLE PANELS, GLASS CD4 INTERMITTENT DELAY WINDSHIELD WIPERS C49 DEFOGGER, REAR WINDOW C60 HVAC SYSTEM, AIR CONDITIONER FRT MAN CONTROLS D14 ARM REST, FRT DR, RH & LH D35 DUAL EXTERIOR SPORT MIRRORS D4D GEAR, SPEEDO DRIVEN D81 SPOILER, RR, AERO WING D88 DECAL, STRIPE, SPORT D9B SENSOR, VEH SPD E5Z SPEEDOMETER ADAPTER (DELETE) E9Z SPEEDOMETER KEY (DELETE) GW6 AXLE REAR, 3.27 RATIO G80 AXLE POSITRACTION, LIMITED SLIP G92 3.27:1, AXLE REAR RATIO, PERFORMANCE J65 BRAKE SYSTEM, PWR, FRT & RR DISC K34 CRUISE CONTROL, AUT0MATIC, ELECTRONIC K90 GENERATOR, 108 AMP LB9 ENGINE, GAS, 8 CYL, 5.0L, TPI, HIGH OUTPUT MD8 TRANSMISSION, AUTO 4 SPD, THM 700 R4 OVERDRIVE MXO MERCHANDISED, TRANS, AUTO PROVISIONS, O/D NA5 EMISSION SYSTEM, FEDERAL, TIER O NK3 STEERING WHEEL, SPORT, SOFT RIM, SIMULATED LEATHER NOD ASSEMBLY PLANT, NORWOOD, OHIO N33 TILT STEERING WHEEL N64 WHEEL & TIRE,SPARE, SPACE SAVER, ALUMINUM N96 16 INCH ALUMINUM DEEP DISH HIGH TECH TURBO WHEELS PB4 LOCKING PACKAGE, WHEELS QDZ P245/504VR16 BLACK STEEL BELTED RADIALS TR9 INTERIOR LAMP GROUP T93 TAIL & STOP LAMP, SMOKED T96 FOG LAMPS - FRONT UA1 HEAVY DUTY BATTERY UF6 LAMP, INTR, CONSOLE, COURTESY UP8 STEREO RADIO INSTALLMENT PROVISIONS UQ7 SUBWOOFER SYSTEM UT1 TONE GENERATOR, WARNING UT4 RADIO, AM/FM-ST CASS, AUTO NR, TOUCH CONTROL, U21 RALLY GAUGE CLUSTER- SPEEDOMETER, TACHOMETER U25 LAMP, INTR, RR COMPT, COURTESY U29 LAMP, INTR I/P, COURTESY U75 POWER ANTENNA V73 VEHICLE STATEMENT, USA/CANADA WS1 PREFERRED OPTION GROUP WITH CC1, N33 AND K34 WS4 MODEL CONVERSION, TRANS AM WS6 PERFORMANCE PACKAGE, SPECIAL HANDLING WW5 APPEARANCE PACKAGE: AERO #5 W62 ORNAMENTATION, AERO PACKAGE YT1 BUILD UP DR & QTR YT9 OPTION PACKAGE, FISHER FURNISHED PARTS 19Q MOLDING COLOR (BLACK) 41U PRIMARY COLOR, EXTERIOR, BLACK 6ZX SPRING, COMPUTER SELECTED, FRONT, LEFT HAND 60P WHEEL COLOR, BEIGE 62D TRIM COMBINATION, CLOTH, LT SADDLE (D) 62I INTERIOR TRIM, LT SADDLE (I) 629 SECONDARY COLOR, EXTERIOR, LT TAUPE 7DB SPRING, COMPUTER SELECTED, FRONT, RIGHT HAND 8NB SPRING, COMPUTER SELECTED, REAR, LEFT HAND 81A STRIPE COLOR, ACCENT, TWO TONE, RED / BLACK 9NB SPRING, COMPUTER SELECTED, REAR, RIGHT HAND On the G92 option ...
"The Trans Am's 305-cubic inch, 5.0 liter engine ... does move the car reasonably well if its equipped with one of the performance rear-axle ratios; 3.27:1 or 3.42:1. Performance shoppers take note. In comparison testing of two identical fuel-injected Trans Ams, the one equipped with a 3.27:1 gear was more than a half a second quicker in quarter-mile and 0 to 60 times than a typical dealer spec car with a 2.77:1 rear-axle ratio. Unless you're keying up for a run at the Bonneville salt flats, you'll probably be sorry later if you skip the performance-axle ratio."

 

To be perfectly honest, I'm not sure. I suppose it's possible that the RPOs don't show the gear ratio. I looked on the rear end cover tag, so I never actually looked on the RPOs on my car.

sorry if I mislead anyone.

 

I don't see anything for the WS codes you listed, but the others shown in my list are for model or package equipment.
YT9 : OPTION PACKAGE, FISHER FURNISHED PARTS

Ratios and rear end stuff is listed under G codes.
Mine GH3: 2.77