OK some might think this is dumb but I gotta ask anyway...what is the top safe speed of an '86 IROC with front 1LE's (if it makes a difference) and 17x9.5 ZR-1 wheels with SPD wheel spacers to fit? I need larger wheels on my car and I have a decent suspension...all poly bushings, lakewood LCA's and panhard rod, 4thgen rear with 3.42's, girdle and posi, all new steering system and beefy swaybars, chopped front springs, 4thgen 1LE rear springs and I'm considering swapping the 17x9.5 ZR-1's on the rear with real 17x11 ZR1 wheels so I can run something more like a P315-35ZR17. My goal is a top speed of 180 mph...ultimate goal of 200mph. When I said road racing top speed WAS a consideration!!! I figure an extra 30 mph over a stock L98 was doable...

Anyway, my main concern is one of the damn things popping off at that speed...at 180mph, it's all over...I'm not concerned with 200 mph since I know there is alot of aerodynamic drag and I'll never really use it but anyway, any thoughts on wheel spacers? I had to press out the stock studs and press in new ones to keep the same thread on the lug nuts as the rear...

Don't burn me. It's a GOAL!

 

why don't you ask SPD?

 

I would say if you're that serious about obtaining those kind of speeds I would buy wheels with the proper backspacing. Why take the chance?

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1985 ASCD Ram Air Trans Am
Readers Ride at https://www.thirdgen.org/rides/index...ew&rideid=1067

-=ICON Motorsports=-

" I get drunk, I race cars and I fondle women. But... I have weekends off and I am my own boss"

 

I felt like I should ask around since SPD is not a large company...I doubt that there is any high-speed testing behind those spacers...

If I could find someone who makes those wheels or similar ones (don't like crap) in custom offsets I would probably do that and sell the ones I have B4 I take a run. Now all I gotta do is find somewhere to do it

 

notto burst your buble, but i had a friend that had a 383 stroker, 671, and i think maby NOS, but anyway the fastest he could go was either 178 or 187 mph, this is due to the aerodynamics of the car, that acually push the car closer to the ground. but what happened was when he went that fast, everything would scrape against the ground, not to mention what would happen if he hit a bump. also you have to get like 2.73 gears to go that fast, or i think you will top off, but im not exactly sure. If you wanna go 200 buy a corvette and take a trip to lingenfilter, they will get you to 226 mph i think.

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90 RS 305 tbi, 4 3/4" cowl Hood, Edelbrock TES headers, Flowmaster exhaust, Crane roller cam, comp roller rockers, vortec heads/intake, ported tbi, w/new injectors, MSD probillet Distributer/ coil, 1 inch tbi spacer, air foil, 14x4 k&n flat base air cleaner, Rebuilt 700r4 w/ B&M shift kit, B&M Megashifter, 3.23 posi, 2 12 RF's with mtx amp, top of line alpine cd player, soon to have 90-91 gfx, z-28 wing, new paintjob, rims, and all new lowered suspension. MSD probillet distributer/ coil,

 

Naw, I got a T-56, 3.42's and an internally balanced 383 stroker...I'm more concerned about 180 than anything else, 200 mph is kinda pushing it but top speed isn't my game...the way I see it, the faster you car can go, the faster you can expect it when driving half that speed (duh)...I know the boxy front end kinda sucks over 160 'cuz of aerodynamic drag so I'm not expecting much above that...but if a stock L98 can go almost 150...

 

almost 150???? hehehehe

 

One thing TA's have over IROC's better aero!
BTW it only takes 600 hp to go 200 mph in a TA.

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86 T/A 5.0 A4 & 2.77 gear
15.62 @ 86 mph
93 Civic 1.6L
13.5 @ 100 mph

 

the fastest camaro is a 82 camaro with basically a stock body other than a 1" lowering and no mirrors. I don't know what kind of engine it had but it went like 236 mph. I saw it in a hot rod magizine(not sure which one) that just shows that our cars are built for high speeds. Corvettes are not the only cars that can go fast.

 

I'm not sure about what spacers you are speaking of? My vett was an 87 and i put the 89 17inch wheels on and i needed spacers. They make spacers so you can put the 17's on the vetts that came with the 16inch rims. The spacers are around 2inches thick and made of some really strong alloy combo. They bolt on with special lug nuts and are said to be very safe. You can get them from Auburn Corvetts for about $250

 

There was a GTA in there once that went 300 MPH. The body was all stock right down to the rear spoiler.

 

There is no way I would try to do any
Hi performance driving with spacers on
any car its not worth taking a chance on
your life.Just get the proper offset rims.
I know thats what you want to here but its
good advice.

 

I thought about it...looks as if I don't have as much $$$ as I need to complete the IROC the way I wanted so I'm going to look at an LT1 drivetrain to drop in with some warming over with parts I already have. I'll keep the rest of the car setup like it is and pop in my ZZ9 and all unless the deal falls through, either way I'll drop in a 350 and see how it works. I figured if I were to really try for those speeds I'd try to find a early C4 TPI vette or hardtop GTA 5-speed to drop a 6 speed 383 combo in, for stability. At least that way I could play with my Z, then replace my carbed 305 in the T/A with a 350 TPI, then get another toy.

It's not my life I'm worried about, it's the other people who may happen to be caught up in that mess. Alot of people don't understand that the faster you go, the margin of error decreases dramatically...at 180 mph it's long gone so you gotta understand that at that speed the slightest driver error will kill you...

that and I don't need to be giving thirdgenners a bad rep, even though I'm a good driver

 

These FAST Trans Ams are all the likely handy work of Gale Banks and crew.