ill be getting a mint shape 85 IROC-Z soon i havent got the vin number, but so far from what i know about it by looking it has

t tops
305 TPI
auto tanny
power windows
over head console
air conditioning
fog lights
the car is black with a red/maroon interior

it may also have a couple other optins such as power seat and locks but i did not look that close. is there anything special about these cars? from what i have read they got an updated rear end and there was some kind of i think G92 package for them in this year. whats all of that about? this is all new to me i am used to my 83Z that i am selling for this car becuase its in alot better shape then my current Z body/rust wise. my 83 Z is starting to show cancer that i dont want to deal with, and the 85 has no rust at all. its just very dirty from being parked for 4 years and only has 93xxx miles on it. i know its still alot but its not in the hundreds yet and again it has no rust at all any ware that i can see. i looked very closely for about an hour over the whole car for rust because i wanted to buy one that was structialy ready for sub frame connecters a paint job and a real engine under the hood and other add ons.

also what kind of an exaust did the 85 IROC-Z get fromt he factory was it a good one or was it restrictive (dual cats ??) lol what type of exuast did it get in 85

I believe the 85 LB9 got a better cam than some of the later LB9 auto cars. 85 is also the first year of the IROC package and TPI.

yes i read that the 85 tpi engine put out more horse then the 86 version, but the 86 version put out more torque do to a different cam. im pretty sure that the 85 version put out 215 hp and the 86 version dropped to 190hp, but produced more torque im not sure about other years i didnt look ahead that far.

Ok first please try to throw in a period now and then. It makes things much easier for everyone to read.

There isn't really anything that makes an 85 special. It did have a better cam than 86, but the ECM is worse. So it's a toss up really as to what year is better. I really can't think of anything that makes an 85 better than any other year. Given the choice of a car from 85 to 87 I'd take the 87. Given the choice of a car from 85 to 90 I'd take the 90. They tend to get better as the years go on.

its an iroc need we say more?

easiest way to check if its rare is check production numbers on this site

I'd have to agree with cdartz that the later models are better. For instance a later model would have disc brakes at the rear as standard!

The only advantage of an 85 over a later year iroc is that in the uk, 85 is the last year where the emmisions tests consist of standing 10 feet of the back of the car with it running and you get a pass if you can actually see the car..... bearing in mind that my one is bright yellow!!

Well okay that is a bit of an over simplification but its about what they do....

Si.

That is not necessarily the case, I have a 1990 Iroc convertible and I have drum brakes in the back. I believe that disk brake rears were an option throughout the 5 year production run and not standard equipement.

It's special because it was the first year for the TPI engine(the big news), AND it was the first year for the IROC model, which had 16" rims(also a first) and a heavier-duty suspension that included Bilstein shocks.

The exhaust is 3" stainless steel through a single cat to the resonator, with dual pipes out of the resonator. That was the normal set-up for the optional V-8s, which came out with the '83 L69 HO engine, which was the fastest of all of them! Ignore the '83 hp rating, lol--that was bogus to get it on the road.

In fact, the LB9 engine is the same high compression L69 fitted with TPI instead of a carb. Hp took a dip in '86, as someone pointed out, but it was back up in '87.

Everything else about the car is pretty normal stuff.

The '85 model IS the year that's most likely to be remembered from the '80s. Well, that, and 1982, when the thirdgen single-handedly revived the American auto industry, lol!

Exhaust wasn't 3", it was 2.75" as were all 3rd gens. Only exception being the Firehawk. And my 84 HO had aluminunized exhaust, wasn't stainless.

85 was a good year for the F-Body. Performance was definitely starting to come around with the new TPI. Wa the best performing 3rd gen to date.

Lots of fun back then, also the last year the 305 beat the Mustang

You're right about 2.75"--except the '83 HO. That was definitely 3" stainless, and probably why I was confused about the following years.

That was the first engine with the wider exhaust, and probably helped it go faster than its "190" hp rating should've allowed. The "word" was that the '83 HO actually made 240 hp. It came out very late and was specifically to kick the Mustang's butt, lol! And it sure did!

I had a friend with an '83 Mustang GT, so naturally, I had to get the '83 HO, lol. It was my baby until it was stolen.

I just found this site today, well, yesterday now. Living in SoCal, where everyone's idea of a performance car is a Civic with decals all over it and a whiny exhaust, LOL, I'm having so much fun reading and posting with REAL performance car owners!

Not to argue, but no way did the 83 have that much power. It ran low 15's completely stock when it was new. Much closer to the 190 rating it got. It would have been a mid 14 sec car with that kind of power, and it wasn't.

85 TPI was the best year only cracking high 14's with a 215 rating and much more torque. That is until the 350 came out in 87.

Hi again.

My test data shows 6.7 to 60 and 15 flat @ 93 in the 1/4 with a top speed of 134. It was rated at 190 hp, but was really 200. There was a "signature" model that made 240hp, but I doubt it was ever officially tested. I only knew the GM exec who drove one.

But looking back at the data, I'm wrong about the 3" pipe. It's also 2.75". Sorry about that. It's been a long time, lol.

[QUOTE]Originally posted by TTA 1387
[B]Exhaust wasn't 3", it was 2.75" as were all 3rd gens.

Check the thread and pics:

https://www.thirdgen.org/techbb2/sho...hreadid=215739

LOL, the stock L69 intermediate pipe (2.75) was bigger than the after market cat back I was previously using on the stock LG4!

JamesC

[QUOTE]Originally posted by JamesC
[B] From cat back, 2.75" was the best any 3rd gen got. Same with the LT1 4th gens. Only exception being the Firehawk.

Not talking about y-pipe as obviously the HO cars(carb and TPI) got bigger ones.

LG4 was even smaller, but note the difference between the after market and the stock L69.

I believe you're correct: 2.75 was the best.

JamesC

The thing that sucks is, the 85 TPI is different from 86+... I don't think much is interchangeable, right?