i need to figure out how far off my speedo is,, what were the original tire size's on a 84 ta (305,th700-r4)??? waht would it be in inches?

 

Well, my 84 Z28 came with (bought it new) P205/65R15's. Your T/A probely had the same size? Anyhow the dia. is 25.5" !

Auggie

 

thanks

 

Well, I gave you the wrong info. It should read P215/65R15's and they are 26" in dia. Sorry !!

Auggie

 

yeah i found that out, no problem.

 

can you figure out the size on a 275/60/r15? the diameter i mean

 

27.99 inches

 

thank you very much

 

I have a dealer sales book for 1984 Pontiac/Buick. Here's the scoop on tires.

Trans Am or S/E (without Special Performance Package WY5, WS7, or WS6)

- P205/70R x 14 Steel Belted Radial RPO QHX (blackwall)
QHW (white letter)

Trans Am or S/E (with WY5, WS7, or WS6)

- P215/65R x 15 Steel Belted Radial Blackwall QYZ (blackwall)
QYH (white letter)

So, check your codes and it should verify one of the above.

 

i cant find my codes

 

fattie, if your 84 has the ground effects it will of had the P215/65R x 15 Steel Belted Radial Blackwall QYZ (blackwall) or
QYH (white letter)

 

yeah it has the "aero package" which RPO is that?

 

there a way to tell if its a WS6 without the RPO's?

 

WS6 included the following:
215/65R15 tires, 15x7 high-tech wheels, limited slip differential, 4-wheel disc brakes, space saver tire, specific springs, shocks, bushings, specific front and rear stabilizer bar, and quick ratio steering
WS7:
same as above less rear disc brakes
WY5:
same as WS7 less limited slip differential

The simplest dead give-away would be if you have the high-tech turbo aluminum wheels (N78). They were ONLY available if one of the above performance packages were ordered.

Hope this helps.

 

BTW, Aero Package RPO is W62.
It was automatically included with the Recaro and 15th Ann. but was available as a separate option on other models.

 

hmm well i might tear my car appart this weekend looking for the RPO's, but heres the low down that i know of. it has the aero package, 4 wheel disk, space saver tire, no limited slip (unless its broke) i dont know what the original wheels were becasue i am like the 4th owner. it already had aftermarket rims on it when i got it. i also think the streering is pretty "close ratio" but thats just because i used to drive a cevy caprice before this. there a way to check the steering to find out? or can i measure the sway bars? also does badging have anything to do with this? my car has NO badges on it other then the one on the front left fog light cover that says "trans am"

 

Since you have the space saver, 4 discs, and the aero your car would of had the 15 inch wheels for sure. There is a good chance that your posi is broken. It happens a lot. You can measure the size of the sway bars to determine if it's a WS6.

 

what size would they be? id just be measureing the diameter? i als remeber reading there there should be a code on the axle houseing that indicates if its a posi,,, whats that code again? and where exactly is it located? maybe i just have the "ws7"

 

Front shaft should be 32mm diameter (#14047917)
Rear stabilizer shaft diameter is less clear since my parts book has the following entries:
- 1984 w/ 305G (ie. the L69) or 305H with Perf. Package WS6 or Handling Packages WS7, WY5 -- 21mm (#10021221)
- 1984-87 w/ Performace Package WS6 -- 24mm (#10035033)

(Some sources I've read list 23mm for the rear. I do know that the 15th Ann. had a slightly stiffer rear stabilizer at 25mm.)

Performance steering ratio was 12.7:1. I don't have time right now to check my parts books to get a # since that chapter is a maze. You're right though, it's a whole lot more responsive than a regular Chev sedan. What I could do is count the number of steering wheel turns on my T/A from R to L lock.

Rear axle code is stamped on the passenger side of the axle tube or on an identification tag attached to the carrier cover. Here are the one's that ARE posi. (Sorry for the long list!)
3.08 6HJ, 6HK, 6PZ, 6EU
3.23 6HL, 6HM, 6HN, 6JZ,
3.42 4PR, 6HO, 6EP
3.73 6PQ, 6HP, 6HS, 6JQ, 6HR

 

ill have to go take a look.

 

fattie92 ... just a thot,

If your serious about decoding your car (and what 3rd gen. owner isn't), grab a copy of the Catalog of Firebird ID Numbers 1967-93. Its compiled by Cars & Parts Magazine and published by Amos Press, 1995. (There's also one for Camaro, GTO, Vette, TBird, etc.) That's where I got the info on the axle codes.

Also, take your VIN to any GM Parts Counter. If the parts guy is in a good mood (and has time) he can punch it into their computer database and it will spit out more info than you will ever want to know!

 

I forgot to mention that I checked the steering wheel on my TA yesterday--it's about 2 1/2 turns from L to R lock. Mine has the close ratio steering so that might give you some idea if yours is the same.

 

ill look, at the moment im trying to put in my hooker cat back....