Anyone know how I can tell if the LB9 in my '87 IROC is the 190hp or 215hp version?

 

Assuming you have a factory convertible (6th digit in VIN is a "3"), you have the 215-hp version. That's because the higher output LB9 came with the 5-speed (which you have). The lower output was always mated to the automatic.

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Willie

Supercharged 1987 305 IROC-Z, Daily-Driver, Emissions-Legal.
12.57 @ 111 mph.
12.04 @ 114 mph (50-hp nitrous).
http://members.optushome.com/au/downunder1/rides/willie/willie.html

1987 "20th Anniversary Commemorative Edition" Z28 Convertible -- Super Chevy Show Class Winner, 1998.

 

i'm not a 100% sure about this, but i think it goes something like if you have the 3.08 axle ratio you have the 190hp one, and if you have the 3.42 you have the 215hp one..

i have a 91z28 convertible and it has the 205hp 305 lb9 engine with 3.08 gears.. the one with 3.42 had 230.. Mine has a 5spd manual too, which seems to go against what willie said in the previous post since i have the lower power engine..

[This message has been edited by Dan91Z (edited January 13, 2001).]

 

Dan,

My information is correct for 1987. The 305 TPI was rated at 190 hp with the automatic and 215 with the 5-speed. The assumption I made about the factory convertible was based on the fact that on the 1987 Z28 convertible, there were ONLY two drivetrain combinations available:

305 TPI with 5-speed &
305 carb with automatic.

On the Z28 (with or without the IROC-Z option) with the TPI/5-speed, the standard gear ratio was a 3.08. On Z28's with the IROC-Z option, you could order the G92 to get the 9-bolt rear axle with 3.45 gears.

Believe me, I know my '87's, especially convertibles.

Willie

 

Thanks Willie. I read over on IROC-Z.com that the 215hp version was only offered in the coupe, so I started to wonder. I do have the G80/G92 rear also.