beaelvsin

I'm new to this forum. I'm looking for an IROC Z to use as a DD, cruiser, and an ocassional autocross/track day. Which year, engine/trans and model type (hardtop, t top, convertible) is best suitable particularly in terms of the autocross/track day? I understand that the IROC cars went through quite an evolution over the years and there's quite a bit out there available for purchase.

FRMULA88

Obviously The newer the better.

Ideally a 1992 Hardtop, TPI CAR, 305 5 speed, or 350 Automatic
either one should be with the WS6 performance suspension. These are the best choices to start with.


Stay away from older base model cars (TBI, V6, etc.) unless your plans involve upgrading the entire drivetrain & suspension.


There is an exception:

You could find s 87-92 Firebird Formula with the WS6 suspension, BUT it may have the less powerful 305 TBI engine

All things being equal the handling will be the same as the TPI models and you can do so some upgrades to the engine.

For their era these were great handling American cars especially with the WS6 suspension, only the Corvette handled better from the factory.

Remember some of these cars will be over 25 years old, and will need some TLC to get them back into top handling shape (tires, ***** joints, struts, etc.)

Have fun and good luck !

beaelvsin

Thanks, FRMULA88. That's exactly what I needed to know.

FRMULA88

You will also find plenty of 305 TPI automatic cars too.

I hate to admit 3rd gens with manuals were not made in huge numbers.


I know when I bought mine in 1994 I gave up the search for a 5 speed car in my area, there was no interweb back then to make the search easier.


It is an easy enough swap to do .. but for my purposes the auto was clearly the better choice.

plum92_camaro

I agree with everything but the stay away from the base model TBI/305 (LO3) part. I use my car like the OP describes (DD, cruiser, autoX, HPDE)and it does very well. There are too many variables to clearly say "get a 305tpi/t5 or 5.7tpi/A4 car".
If you are set on getting a true IROC or Z28, then by all means get one, I would. If you are planning to mod the car over time (which you most likely will when you replace the old worn out stuff a lot of these cars have) then why not consider an RS/base model? They mod just as easily as any other 3rdgen. You can always change the badges when the mods live up to the name. My 92 RS and i'm sure many others came with everything you could get in a Z28 except the wonder bar and TPI. The wonder bar was $50 and the looks i get when people find out they got beat by a base 305 with less than 200hp is priceless.

If you plan to do some drag racing with the car too then get a 5.7tpi car and swap in a t56 (i prefer a manual). Otherwise please keep in mind that in autoX, horsepower means nothing. Its all about driver, suspension, and grip. The track record holder here set it with a 90hp subaru with full suspension and slicks. The guy barely even brakes for corners. The bigger the tracks (longer straightways, where the "drag racing" happens) you want/need more power but for small tracks like autoX a TBI, even a V6 (best balanced models) with suspension mods can dominate and be replaced with an LS or whatever down the road.

Food for thought. Good luck!

plum92_camaro

BTW, i have t-tops and no issues yet. i have UMI SFC but haven't installed them yet. They will be in before the LS1/t56 swap is done. Having t-tops is not a death sentence for a autoX/RR thirdgen but just like a hardtop thirdgen, SFC's, a STB and/or a cage would be a good idea.

IrocRoadRacer

Get a 1989 IROC with the L98, and mount up a T56 with a 3:90 gear 9 bolt. The 1989 IROC doesn't have the annoying airbag and cold start injector.

Racinfreak84

STill looking for an IROC?

http://www.ebay.com/itm/251578476901

That's mine, has a youtube video with it.

Needs struts/shocks, rear gears, and maybe a higher capacity radiator and you're set. I'd also suggest welding in subframe connectors. I'm moving cross country again for the 4th time in 4 years. I'm done moving 4 vehicles. Excellent car. I've had it since 2002. Before then my great uncles since it was new.

355 340hp complete gm rebuilt/refurbished 350 that was bored .30 over. Great for autocross.

Homer23

The best IROC would be one with a T5 trans and the TPI engines with the performance suspension package. If you happen to get one that doesn't have a wonderbar, buy a factory one. If you want to be competitive in autocross, be deliberate and selective in your modifications because one suspension part replacement can put you into a fully prepared class that may require a stripped out race car to be competitive. So slow down with the mods, but make sure you get Bilstein sport or Koni yellow shocks and struts, or something more hardcore than those. Also plan on getting at least bolt in subframe connectors. I wouldn't look at automatics personally because they're not as fun for DD and they don't offer enough performance during autocrosses and track days.

The hardtop is best because the chassis is stiffer than the others and you don't have to worry about extra maintenance with water leaking. A convertible is the worst choice because for track days, most of them will require you to have a 4pt roll bar or a hardtop, and I don't think there is a hardtop for Camaros or Firebirds, not to mention the extra weight.