C3 engine differences
Thread Starter
6th Gear
Joined: Mar 2002
Posts: 6
Likes: 0
From: Miami FL
C3 engine differences
hello all. im new here, and im in the process of looking for a nice C3 vette to restore. i like the late 60's- early 70's look when they still had the chrome front bumper, but i read that between 69 and 75, the horsepower went down dramatically for the 350 engine. what caused this? lets suppose i get my hands on a 74 C3 with a 350, just how much is involved in getting about 300 flywheel hp out of it? thanks guys. by the way, NICE CARS!!!
Le Mans Master
Joined: Mar 2002
Posts: 7,456
Likes: 2
From: Coming home from Luckenbach Texas
Re: C3 engine differences (Donate52)
Two words: emissions controls. By 1975, the poor Vettes were choked with AIR pumps, restrictive catalytic converters, etc. If you live in an area where old cars like that still require testing, you're going to have trouble. But if not (and you don't mind making the Sierra Club mad), it's easy to increase HP . . . just remove the junk! I test drive a "desmogged" '75 with an L48, and she hauled along real good! :yesnod:
Race Director
Joined: Apr 1999
Posts: 15,143
Likes: 477
From: NM
Re: C3 engine differences (Donate52)
From 70-71 they reduced compression getting ready for unleaded gas and that caused a small drop. In 72 they changed the rating systems from the GROSS HP rating used prior to 72 to a NET HP system used in 72 and after. Same engines just different rating systems. But in 75 the cat converter and heavy emission controls came along and there went the hp for awhile.
tom...
tom...
Thread Starter
6th Gear
Joined: Mar 2002
Posts: 6
Likes: 0
From: Miami FL
Re: C3 engine differences (page62)
well here in FL we dont have any emissions testing. so lets say i had a '75 vette, by removing the air pump, cats, and boosting compression to around 10:1 i should see a nice increase in power, correct? thanks for the help!
