no it's not tuned port but it's 4 bbl but i thought all irocs were 305 h/o.

 

Not all IROCs have the 305 ho. My 86 had TPI on it with the standard 305. If its a 4 bbl then it may have been modified by someone. If your the only owner then it may have a q-jet but I thought the last ones were put on in 85?

 

Carbs were used through the 1987 model year. TPI started as an option in the 1985 year model.

The only "HO" models were carb'd 305's which were the VIN G L69 models, primarily in the 1983 - 1985 model years, with only a very few made in the 1986 model year. Those that have a 1986 HO generally know it without a doubt.

An IROC, Z28, etc., appearance package is no guarantee of a "high performance" engine.

 

check your RPO's they are on the inside passenger side of the center console, if not you have to run your vin which is on the windshield, inside the passenger side fender , trunk etc.

RPO List

B4Z IROC PACKAGE
1FP87 Camaro Z28 Sport Coupe, 8-cylinder

You can still have an LG4 and have an Iroc, just really smogged Iroc.

 

In that rpo list, it shows only 2 available codes that start with 'G', I was wondering if that was a complete listing of the codes? I have an 88 and I am wondering if I have posi, I have 1 'G' code listed on my sticker, but I cant tell if it's a g80 or not. The other 'G' code says it's for z28 only, I have a mpfi 2.8 v6 (non z28 obviously). The sticker is damaged where the code listing is, so I can only see that it is a code that starts with a 'G'

Sorry, not trying to steal the thread.

 

im pretty sure all 88' sixers are open

 

Open?

 

open differential, not posi only one wheel spins you could convert it for a couple hundred but with a 2.8 it would have to be for safety reasons.

 

There are a lot more 'g' codes: http://www.nastyz28.com/rpomenu.html

My '87 2.8, has 'GU6' = 3.42 rear axle ratio

 

My Iroc came with an LG4, 700r4, aluminum rear drums, and a 2.73 open differential ... It now has 355 and 3.73/eaton posi.. Just upgrade!