Hi guys. I recently became aware of this whole board via some friends of mine on thirdgen.org. This looks like a good forum for me to be on and I am hopeful to learn as much as I can by reading some of the forums. I will make sure to search for the info I have questions on, and I will always keep things tech related.

I've had my 1987 IROC for 21 years now and it was my high school car. Years later after I made it look real nice, I got bit by the quest for more performance. The car is indeed a true real-deal street car that I use for autocross, short course road racing, drag racing, car shows, and general street duty. I do not own a trailer and street drive it wherever I go. My parts selection is based on those factors, so I have quite the balancing act to do when it comes to picking parts.

I have competed in the Optima Batteries Search for the Ultimate Street Car series in 2016 and also in 2017 (both at New Jersey Motorsports park)
I have also competed in the UMI Performance Autocross challenge in 2019 and 2020.
I also have done a handful of other autocross events in NJ and PA as well.


I enjoy the heck out of the car, but I know it will never be competitive in any specific CAM-T class or competition. For me, it is all about building/driving the car to find its potential, and then learning what I can do to take it a step further.


As mentioned, its an 1987 IROC-Z. It has a 406 small block chevy with a dart block, dart heads, callies rotating assembly, full roller valvetrain, and I use the holley sniper efi. I know the automatic trans is not optimal, but it is what is staying in the car. it consists of a ProBuilt Automatics 700R4 built with their tiop level package, and a 9.5" Edge Racing 3,400 converter. A 3" driveshaft from Dennys, and a Moser 12 bolt rear axle with 33 spline axles nad a tru Track. It currently has 3.55 gears, but In February it will get a gear change from 3.55 to 3.91 gears. Also, the engine was built with nitrous in mind and it will indeed be getting a 150-200 wet shot soon.

Front:
I have the C4 HD 13" brake package up with Hawks HPS pads. UMI A-arms up front with Koni Yellow struts and UMI upper strut mounts. OEM sway bar with poly mounts. Replacement Moog springs and a 2" drop-spindle setup. Replaced everything to the steering system with new components and had the original IROC-Z steering box re-built this past winter so it is very on-point. Wheels are 18x8" with a Nitto 555 255/40/18 tire that I would love to replace.

Rear:
UMI adjustable lower control arms, UMI panhard bar, Founders performance upper panhard bar. OEM swaybar with poly mounts. Koni yellow rear shocks. Moog springs with 3/4 coil cut off. C4 rear brake conversion so 12" rotor with powerstop pads. 18x10" wheel with a 285/40/18 nitto 55 tire. Also looking to replace these in the spring.


Here are some photos:



















here is a link to some of my photo albums of events and my car's build over recent years:
https://www.flickr.com/photos/iroczman15/albums



I also have a youtube channel, and while I do not do any editing or creative video work, I do have some videos of my autocross runs over recent years. if you search through the "My videos" section. My username is the same as it is here IROCZman15

I am also on www.thirdgen.org using this username and I have a couple of long "build" threads and some racing info there along with photos, datalogs, videos, and tech info.

Glad to be a member here and looking forward to what I can learn after I spend some time reading.

Welcome, we met at an SCCA event.

That is one beautiful engine compartment...

Welcome! It's always nice to see a carb and distributor in a 3rd gen!

I never figured out what exactly killed my 700R4 at an autocross besides "heat" from doing 26 runs in only a couple hours. It had a shift kit and allegedly had a "Corvette servo" (which all 4th Gen automatics have I guess). I can't remember how many total runs it had, maybe 75? One track day with two drivers as well. But I never put the car up on stands and let it run through the gears a bunch of times after it sat for 8 years (which, at the time, I didn't know you were supposed to do to automatics after they sit that long). Basically what I'm getting at is how you keep the automatic from killing itself when things get hot. Is it just the quality of the ProBuilt trans and the upgraded components or do you have a better cooler than the stock setup that runs through the radiator end tank? How does a high stall converter like you have help or hurt? I feel like a high stall converter would run hot in an AX/RR environment. I don't have an automatic anymore, but if I wind up with another one one day I'm curious. I don't feel automatics negatively affect autocross times except for maybe maintenance throttle in corners being too overzealous due to the torque multiplication of a torque converter. But a high-stall one won't do that as much below the stall speed.

While the quality of the build is important, the high stall converter makes lots of heat in AX. You need lots of cooler and possibly an electric fan on the cooler, and, if you are using the cooler in the radiator, it must pass through it first, then to the external cooler, THEN back to the trans. I ran a 700 in the Corvette with 2 drivers, my motor and a 4800 stall converter with no issues, but I put a huge cooler on it.
The converter is really determined by the cam, car weight and rear gear. Like most things its a combination of parts that make horsepower.
In my case, you had to LFB and keep the engine around 4500 to get smooth throttle transitions. My co-driver found out on more than one occasion the smashing the throttle from idle at the Apex resulted in lots of smoke and the need for excessive steering input... your results may vary...

IROCZman 15, I see you have a trans temp gauge; I'm sure that helps. We had no idea how hot the transmission was when we killed it.

Was your car originally a 350 TPI? If so you won't need bigger sway bars since it's an '87.

I really should have had more converter due to my cam. IROCZman's car with a matched converter is probably less of a part throttle and idle nightmare than mine was with the stock converter. That had been driving me INSANE since 1995!

Oh and a NASCAR motor like Racerdad's isn't built for an automatic for sure; I can see why you went all the way up to 4800 on the stall!

Wow, cool, glad to see so many replies. Thanks for the compliments too.
-sorry for the wall of text that follows, I just wanted to answer some questions and give some more details.


Hey, slowTA. Was it at the Meadowlands event or Warminster that we met? Also, I'm not sure if it is a typo.... but do you actually live in Kenvil, NJ?? as in Roxbury Township?? If so, thats crazy!! That's the town I currently live in and have lived in for 8 years now. How wild is it that the first person who responds to my member-intro post actually lives in my hometown? What do you drive? I am sure we have seen eachother locally.

RacerDad: It is actually the Holley Sniper EFI system, which is built to look like a carburetor, but is a throttle body style fuel injection. The car used to be a tuned port TPI setup on the 305 engine. I also used to spray a 100 and 150 nitrous shot at it and it all held together after close to 30 bottle of nitrous in 5 years time. My personality just loves the old-school look of a simple engine bay and a gen1 small block chevy was all I was interested in putting in the car. I know people have amazing success with the LS1, LS3, LSX platform, but I wanted to open the hood and just see a high-horsepower small block chevy without the coil packs, or tons of wiring. I did want fuel injection and the ability to tune, and to datalog, so I went with the Holley Sniper EFI and the hyperspark ignition to match it. it all works great. I'm a novice at tuning and reading datalogs, but its only been 1 year now and I hope to keep learning. The engine made 531 horsepower at 6,000 rpm and 513 ft/lbs of torque at 4,800 on an engine dyno in February 2020.


As for the converter and the trans temps, I had this decision to make back in 2016 when on the way home from competing at the Optima batteries USCA event down in south jersey, I guess the trans was super hot and I was loaded down with several hundred pounds of tools during the 3.5 hour drive home.. after racing several sessions of the road-course segment that day....I melted the stock transmission and converter down. It made it home, but the trans was hurt bad! I debated the t56 swap, but knew I kinda wanted to keep this car an auto. I had extensive talks with Dana who owns ProBuilt Automatics and we agreed that building the trans with his top level kit would be the way to go, because even back in 2016 I knew I would be soon installing a 500+hp engine and spraying it with a 200 shot of nitrous. He redesigned his website recently and also his prices are now higher. I think I paid about $2,700 for it a few years ago. https://probuiltautomatics.com/shop/ols/pro...elite-1988-1993
- the converter was selected to be a blend of all motorsports worlds that I am in...launching at a drag race or a ripper on the street, plus not having to rev it to the moon in an autocross event. Drag race guys tell me I should use at least a 4,000 converter; yet it would be better to use a lower rpm converter for autocross. When the trans melted down I put in the trans temp gauge, so that I would never overhead a trans again. The trans temp sensor is in-line on the return line which most people say is the best location for it (not in the pan or trans case or outlet line) My temps are always surprisingly super cold/low! Even during the MSNE autocross event I did mid summer 2020 when we did 7 back to back passes, the trans temp only peaked at 180-185. Normal driving, usual drag racing,and usual autocross the temp is usually 140 or so. I have the fluid exit the transmission, pass through the bottom of the aluminum radiator (champion 2 row rad with puller fans) and then the fluid goes to a medium sized B&M style cooler mounted behind the front nose and exposed to air passing over it. I do not have a fan on this B&M cooler. I also run an in-line magnetic filter for the trans fluid which I check every year.
- one BIG piece of advice that Dana gave me is to add in 3-4 quarts of CAT (caterpillar) Automatic Transmission fluid. Its properties are super helpful for the internals of the auto-transmissions especially in road race cars and whatnot. He highly recommends this, so I use 4 quarts of CAT fluid. he also says that for road racing cars or drag racing to overfill the trans fluid by 1/2 to 3/4 of a quart of fluid because of the G-forces and the extra fluid will help keep the pump from sucking up air.

Yes, the car was originally a TPI car, but with a 305. I used to remember some of the important RPO codes....but I do know that the front sway bar is a 32 or 34mm and the rear is 23mm. It has the IROC bars, thats for sure. I run the polyurethane greasable mounts and polyurethane swaybar end-links which I shortened the spacer up front to get the bar to sit level (after the 2" drop springs went in) I do take the front sway bar out for drag racing, but keep it in for street driving and autocross. I've contemplated going bigger, but I am not entirely sure I need to spend the money on bigger bars.

I am switching out my 3.55 rear gears for a 3.91 gearset in a few weeks time...but I think the biggest improvement I want to make to the car related to autocross for 2021 is to find some money to get a better set of tires. My 300 treadwear Nitto 555 tires are 6+ years old and not great in the corners compared to these guys on BFG rivals and whatnot. Tires want to slide around a lot, its a delicate dance at times. With my wheel sizes, I don't have too many tire options, but I do see that Falken has made a new tire ( RT660) and I am waiting to see how people like it. The tire also has to look right on the wheel and fit the wheel well of the car right too since these wheels and tires are my show car and street car wheels. I use drag radials and skinnies at the dragstrip.

glad to join up to the site!

As far as the RPO codes go, the big swaybars (36mm solid F, 24mm rear) and springs (750 front specific to the 350 but 107 rear like everything else) are built into the L98 in '87 so there is no G92 that year on the 350 cars -- it is built-in G92. Can't remember if the 305 TPI cars had to spec G92. Anyway 32-34mm front are still pretty big since we don't know where your spring rates are at and 23mm in the rear is plenty big if not too big. Depends on setup. You're probably pretty close already and you're getting to the point where you know the car well.

Awesome car! Always cool to see a clean 3rd gen. I also agree with keeping cars multipurpose even though I tow my car to the track more for convenience, it is still a registered and inspected daily. It just doesn't seem as fun if I can't drive my track car to work!

Have you ever made it down to VIR? There's a great group that I run with there (mustang group ironically, but really cool). There an event next month but too cold for me, I'll be there in April though.

We met at Giant stadium, you have a bunch of pics of my Firebird in one of the links you posted. I lived in Kenvil up to 2016, then moved to Budd Lake... that means it's been a LOONGG time since I've updated my profile here! My car is only street driven to get gas and the odd test drive, I can't remember the last local car show I've been to. I think I only went to the IHOP car show down the street from me twice the 7 years I lived there! LOL, 2020 hasn't made me any more social either!

GC; yea that makes sense. I'm pretty used to these sway bars and at this point I think I am leaving them as is for a while. But what you are saying does make sense to me

mike: cool. yea. Even if I ever do get a trailer, the main concept of this car will always be a street car. perhaps I will have another car one day that is a track beast, but just not this one. I have not made it down to Virgina for any racing events. Maybe one day I can!

slow: Ah! thats right! we did meet at the Giants Stadium event, I think that was 2018. In fact I think during the early morning drive there we were both on route 80 east side by side for a little bit. Glad to re-meet ya then.

That's how I am. I don't like mods that take a perfectly fine street car and make them evil on the street. Having been around race cars, it's better to just admit you want a race car and buy one separately. Especially since used race cars (that aren't done wrong) can be such a good value. Of course for me that comes with a truck and trailer bill though since my truck is a 4cyl 1st Gen Colorado.

yup. same here. I have a goal every year to put at least 3,000 miles on the car. Been meeting this goal for the past 9 years in a row. It only takes half an hour to get it autocross ready and probably about 2 hours to get it ready for the dragstrip. otherwise its fantastic to drive on the street. I do want to have a different car that is purpose built for racing, but that will be some time into the future. As you mentioned, then I also need a trailer, a second set of tools for the trailer, a bigger budget, etc. Luckily I have a truck, but it is my daily driver so I don't want to kill it constantly towing .

Anyways, just wanted to introduce myself here and I am sure I will have some questions to research and ask the group.

Nice 3rd gen! I see you were at UMI, I have been there the past 2 years at their "regular" event, not the Optima or KOTM. I live in central PA so I'm at all the CPR region events, I'm the solo chair.

yup. I have only done the "regular" UMI events.... The one known as UMI AUTOCROSS CHALLENEGE. The Optima events I have done were at NJMP and also were not the newly created Optima Batteries events at UMI Motorsports Park. sounds confusing when I type it! haha. what were you driving at the UMI events?

Welcome aboard
Car looking great

Welcome! That is one cleeeeeean looking engine compartment!!!

thanks guys! I took a lot of time doing the engine compartment this past winter; I enjoyed doing it though




it was like this as of last January!

I do my best to keep it clean, but I have no problem hammering down with the car on the tracks and using the car as a performer.
I am not a shop owner or anything, just simply a guy with a hobby.














currently the rear axle (moser 12 bolt) is out from the car and tomorrow I am pulling out the 3.55 gearset and changing over to a 3.91 gearset. With the car being a multi-use car, I still want more brutal acceleration on the dragstrip and street and these gears will do it. It might cause me to have to be a bit more easy on the throttle pedal when coming out of the turns during autocross, but to me the 3.91 gearset was the right move. I will find out soon!

Is that an Astro van or Jeep Cherokee XJ steering shaft conversion? Looks different from stock. If so, do you like it?

I'm curious about the steering shaft too... but one of my pet peeves about this car is when people don't paint under the upper strut mounts. Hopefully the alignment doesn't need to change! I measured from the strut nut to the firewall and fender to get them back it the right spot and the car has been aligned a few times since then too.

yes, the steering shaft is an Astro van unit that was refreshed and built by a fellow Thirdgen guy names Matt Walter. He has a small company selling raceparts, but I had met him in Carlisle back in 2015 at the GM nationals where he was selling them, so I bought one on the spot. It is awesome. No deflection from the stock style rubber components. Just u-joint shaft.
https://walter-racecraft.myshopify.com/
or
https://walter-racecraft.myshopify.com/coll...d-78-87-gbodies


In hindsight, I totally should have painted under the strut tower mounts. I kick myself when I think that I had no sound reason not to, aside form that I was very happy where the car's alignment was at the time. After everything was painted, I decided to pull the strut mounts and spray paint them black because they looked dull next to the fresh new red paint. I know that I could have and should have painted underneath them.