Phx89Iroc

Hi everyone, i have been wanting a convertable iroc for a long time and finally got one. I was told it was a 350 5.7, but after looking up the vin it said it was a 305. I thoght i got scammed so i started doinng more research, and i also see it has a sticker right behind front wheels saing tpi 5.7 liter, and under the hood somone wrote in paint marker 5.7L then i finally noticed on the door a sticker from ASC saying the car was modified in 1988 and still fits general motors regulations. Different sites online said that this was a common thing to do, to modify the engine to a 5.7 by this company asc.

What i am wondering is why was this done instead of just buying from fatory as 5.7, did bigger engine convertable not exist in 1989 models, and is the asc modification just as good? Is there any difference between the factory and the conversions?

Im just learning about my iroc, i had an 88 RS before with a 6cyl tpi so know the basics.

305sbc

iTrader: (3)

Look on the rear of your engine block on the driver-side just below your distributor. There should be a "5.0" or "5.7" cast into the block about an inch away from where the block meets the transmission bell-housing.

I think the factory chose not to install the 5.7 in certain option cars because they were not as confident warrantying such combinations.

In most aspects the 5.7 is identical to the 5.0 engine, and the casting mark I mentioned is the easiest way I know to determine the difference externally.

Phx89Iroc

would it still say 5.7 if it started out as a 5.0, and then was converted as i menion?

RedneckNo4

If you unplug the IAC and look straight down there is a tab you might be able to read... that'll tell you as well, that seems much easier to me but its probably rusted over


yes it would

Phx89Iroc

what is the IAC? thanks (im still learning)

305sbc

iTrader: (3)

Yes it should because it will have to be a 5.7 block.
A 5.0 block cannot be converted to 5.7 liters. The engine has to be swapped.

Dante93GTZ

iTrader: (5)

First indicator of what it WAS is the simple fact that it's a convertible - No IROC Vert was offered with a 350, from the factory.

If you were told it's a 350, you can verify that by two things. #1: Behind the drivers side head, you will see the engine size, either 5.0 or 5.7. Sometimes it's hard to see, but its always there.

#2: If you can get under the car, you'll see 3 digits on the side of the block - If you can get us those numbers, that may tell us what size it is.

A couple things to consider - There is more to a 305 to 350 TPI swap than simply switching engines. You also have to consider the fuel injectors, and chip - Both were different between the two engines.

t-topsavage

The optional 5.0-liter V8 was standard in the IROC-Z. It now had throttle-body fuel injection and 5 more horsepower. 2 MFI V8 options were offered for the IROC-Z. They were a 5.0-liter H.O. (which put out 220 hp with a 5-speed manual gearbox and 195 hp with automatic transmission) and a 5.7-liter 230-hp edition that came only with a 4-speed automatic transmission.

Barely 1,000 Camaro convertibles had been produced during the 1987 model year, but the numbers rose to 5,620 in 1988 when the revived body style had its first full-year run.

RS models (7,038 sold) were available in limited areas (California, Texas, and Florida only).

All 1988 Camaros (except the IROC-Z with the 5.7 liter V8 which required automatic) could be had with either a 5-speed manual gearbox or 4-speed overdrive automatic transmission.

The mighty IROC-Z came only with the 5-speed manual transmission as it's standard transmission.

***** "Factory" Convertible or Not: *****

To recognize whether a 3rd-gen convertibles (sometimes referred to a "ragtop") is a "factory" or an aftermarket job, the best thing to do is to check VIN number. If the 6th digit is a number "2", that indicates a factory coupe and a later aftermarket conversion. If it was ordered as a convertible, the digit will be a number "3". Another clue is to look at the RPO code sticker that is located on the inside of the center console glove box (if the cover is original). Factory ragtops will have a code "CC1" (T-top coupe) as well as the code "Z08" ("Model Conversion, Convertible").

Note: There WERE Camaro IROC-Z Convertibles produced with the L98 350 engine (installed by ASC at time of coupe - Convertible conversion) however this was not a GM feature or option. As a result, you will NEVER find a 1988 Camaro IROC-Z Convertible with a "3" as the 6th digit (Convertible) AND "8" (L98 350-cid) as the 8th digit in the VIN number.

IROC-Z coupes could have a 350-cid and so the 6th digit would be "2". The customer could then have their coupe converted to a convertible which would mean it would have a 350-cid engine. However, only GM stamped the "3" on the VIN and so the 8th digit will NEVER be "8" and 6th digit a "3".

Oh and IAC is "Idle Air Control" solenoid.. If you take it out it has to be readjusted.. thats a bitch.

Phx89Iroc

Thanks for the info. I did look up the vin yesteday it did confirm that it was a factory convertable, with the 3 digit and not the 2. Im assuing that becuase it does have the asc sticker on the door saying it was modified, hopefully it's legit. Ill have to look up the code on the side of the block when i can get under it later this week.

RedneckNo4

the IAC is the Idle Air Control module, its on the throttle body (that's where the cables attach to at the front of the intake)
(if standing in front of the car looking into the engine compartment) on the left side on the bottom its a squarish 4 prong plug

VincentZ28

iTrader: (2)

All rag top cars are modified T-Top cars. The T-Top car were sent to a company to converted to rag tops because T-Top cars have special bracing in the body to keep it from tweaking. No factory F-Body convertable came off the assembly line.