I found a 1989 IROC for sale with a "5.7L 350" in it. the VIN digits match that description because of the 8 in the 8th digit - but under the hood it has the same TBI air cleaner & assembly as a 305 TBI third gen...

The car has the "5.7L Tuned Port Injection" badge on the back, rear drum (not G92), nice paint, nice interior, AT 4sp, t-tops, etc $4500 120k miles

In 1989 all the 350 iroc's came with TPI. Did someone swap the TPI > TBI? How can I know?

 

First welcome to TGO
In a F-Body the L98/B2L 350 only came with TPI in the US cars as far as I Know.I would check the block stampings on the passenger side block deck just in front of the head.This will give you the block code,build date and the sequential VIN for the car.There are casting numbers for the block and heads you can check at Mortec.
If the VIN eighth digit is an 8 then she is an original 350 car that has either been converted to TBI(for what ever reason).Or it's a 350 out of a Caprice/Impala/C-K pickup(I believe the code is LO5).

 

Under the hood, it has the alternator on the drivers side. So it basically looks like this, except not as shiny:





We can check the head casting number by removing a valve cover. OK - but how difficult is it to access the block code on the passenger side ledge? Can anyone confirm that the code is actually located there? Keep in mind that the alternator is on the drivers side for 1989. I don't think the seller is too excited about me showing up in his driveway with a bunch of tools. Are there any quick instructions for accessing this stamped code? (plz no crowbar jokes)

 

No third gen came with a 350 tbi only 305 tbi and if it was a 350 it had tpi so you can put that to rest.Now you have to figure out why someone would go through the trouble to switch it over from a tpi to a tbi,also you might want to make sure that that is the proper vin plate for that car people have been known to change them and get away with it since most people cant tell the difference between a rs and an iroc so be carefull if something doesnt seem right dont do i would hate to see you lose your car or have to deal with the cops at all i believe there is another guy on this site with a yellow camaro that went through the same problem so be carefull

 

Bump. Any advice or experience with this is appreciated. Anyone familiar with a third gen 350 w/TBI? Ever seen one or driven one? How was it. Do you have photos? And why is it TBI instead of the original TPI?

 

they couldve just changed the badging because some IROCs came with 305 and im not positive here but if i remember correctly some were even tbi and he could be trying to pass it as a 350 for more money but who knows.

 

The stamping should not be on the passenger side, but the driver's side. It will either say 5.0LG for a 305, or 5.7LG for a 350. Then you take the oil cap off and you might be able to see the casting numbers for the heads. 083's are iron 350 TPI heads.

Another thing to check, is look at the RPO code in the center console. I think there is a VIN there, so check that against the dash number. See if it says "L03" or "L98" in there. If that VIN doesnt match, there is one in the trunk area, but thats not important.

Regardless, I would pass on that deal. Even if it was a true 350 TPI thats too much money.

 

Dude...I had a friend who bought a late 80's Maro with a 4 barrel 305 and the guy told him it was a 350. The thing never felt like a 305...we always thought it was a 350...it was stick and the guy put an Edlebrock intake on it. It was real fun...well...when the first oil change came up my friend went and got all the tune up stuff for it and the oil filter and a few other things weren't the same...low and behold...305...still a fast car but it wasn't a 350. Dude's do that because they want to get more for it.