Were they rated for 275 in all the years or no?

 

The LT1's were rated as follows:



1993-1995 w/Single cat. - 275hp

1996-1997 w/Dual cats. - 285hp

A couple late build 1995's also had dual cat's

 

Please note the above numbers are F-body only. The B-body LT1 was 260hp and the Y-body (Vette) was 305. There are also 1996/97 Firehawk and SS F-bodies running around at 300hp. Topped, of course, by the 330hp 1996 LT4 Y-body's.

 

LT1 vette was an even 300hp when it came out.

 

Sorrt I just thought since this was an f-body site thats all he cared about.

 

LT1's were underrated from the factory. Mine dynoed 251rwhp/296rwtq when it was stock, except for a cold air box.
Figure in a 20% driveline loss, since mine is an auto, and you get 313hp/370tq at the flywheel. I don't think a cold-air kit is good for 28hp. Maybe 8hp, so these cars are actually around 305hp, not 285.

 

What? GM understating the power output ratings? I've never heard of such a thing...