A while back i picked up a 86 iroc out of a pasture and as im pulling the car apart i figure out it has a 9 bolt rear disk. But records only show that the fake 350's came with the BW. Could the car be one that was suppose to have gotten the 350 but got the 305 instead?

 

The BW rear was offered in the Firebird as early as 85. Normally I would expect to find a 10 bolt under an 86 Camaro, but it's not all that unlikely that some may have been built that way. I'd check the RPO codes to see if the gear ratio listed in the RPO's matches the ratio in the rear end.

I'd be confident in saying that the rear end has nothing to do with the rumored 86 L98 cars... It's a lot more likely that someone wanted better gears or rear discs so they swapped the rear.

 

if was any other car i would agree with you on the swap. But this car was a 1 owner and driven by an older gentleman before it was put out to waste away. Im going to find the rpo codes and see.

 

plus it would be kind of cool if the car was the select few to recieve the 350 but after they changed their mind it got the 305 instead. Its got every option for an iroc.

 

You can search and read up on 86 L98 cars, but I'll save you the time. GM probably didn't build anywhere close to 50 of them. The real number is probably less then 10. Those cars if even built were almost certainly destroyed when GM was done with them. It's not like GM had them on the assembly line, couldn't get the 350 approved, and just threw a 305 in them instead to sell them through the dealers. Check the VIN number... If the 8th digit is anything other then an 8, it was never a 350.

 

Hello johnson7454!!

Beware of the 1 owner/dealer demo story line!!

I own a "1 owner" (me) dealer demo 1987 IROC with a swapped out BW 9 bolt with a 3:27 gear ratio!!!

My RPO codes tell me my car was built with a BW 9 bolt with the 3:45 ratio, but I bought it (unkowingly at the time) with a swapped out rear end!!!

Car was built 02/87, I bought it 04/88, and it was registered to two dealers before I bought it!!! I know this is fact, as I had a vehicle title history search done!!

The car had some painted on numbers on the rear end, that I noticed about two months after I bought it while getting some service done, and was told by the dealer service tech, that the numbers looked like junk yard markings!!

Maybe your one owner car has the same sort of history as mine!!

Why the rear end was swapped, and who did it, remains a mystery, but I can give some pretty good guesses!!!

 

 

you missed my point. I never said this car was a l98 car nor do i believe they ever made the 86 l98. Bascially what i meant is that this car probably got a left over rear end and that rear end ended up being a 9 bolt. Which wasnt even suppose to be offered until 88. The vin shows it is a 305 car. Im not trying to start a 86 l98 thread. I guess i should have worded my statment different. But it still doesnt stop certain cars being set-up for certain engines and then a change is made. Just doesnt make any sense for the car to have a 9 bolt before it was offered for the camaros.

 

i agree but i didnt buy this car for restoration. Its a part out for my other iroc. That is something strange though for a dealer to do a swap. But that is 88 where this one is a 86. Ive actually got all the paper work from where the guy bought it. Wasnt a dealer demo and he bought it just a few months after production. Now im not saying its the stock rear but everything sure does point in that direction. The rear is untouched. Still got the dealer decal and stock brake pads.

 

maybe what i meant is that the 9 bolt in 86 could have been meant for the l98 but got stuck under a high option 305 instead.

 

No, I got your point... But what I'm saying is that the BW 9 bolt was already on the assembly line. As early as 1985 GM was dropping the 9 bolt into the Trans Am. The 86 L98 Iroc never really got that far. It's not like the plug was pulled at the last minute leaving a pile of parts sitting there that they had to burn up.

Again, what I'd suggest is verifying what you really have. Doublecheck the VIN and the SPID and see if the car even came with the rear end stock. It's possible the tech data is incorrect, it wouldn't be the first time. But without the documentation to support that the part wasn't changed, there's no way to know if it was original or if someone changed the rear after the fact.

 

First check the date coding in the axle housing and you'll know if that part was even made in 1986. If it was a 1986 axle housing, check further to see if the gear ratio matches the RPO for the gears, you said earlier you were going to check the RPO codes. So what have you found the RPO codes to be as you said you were going to do in post #3? I can't hardly stand the anticipation of what you'll find. Please don't keep me waiting any longer for the news. Please post it tomorrow if possible. I've been following this with great interest.

 

Hello johnson7454!!

What is the code on the "dealer decal" on the diff cover?