1975 L 48 Corvette Speed?
Race Director
Joined: Apr 2007
Posts: 14,062
Likes: 602
From: Henderson Nv-Rohnert Park/Sonoma C o. ca/born in NY Rockaway Beach.
Team Owner
Joined: Jan 2006
Posts: 37,637
Likes: 3,118
From: Crossville TN
It all depends on what axle gear ratio you have. A 'standard issue' '75 would likely have gone 110+ mph as shipped. With some tuning, it could probably get near 120. Either you have a gear ratio that won't allow you to reach higher speeds, your engine is 'sick' (or in poor tune), or you are not getting full opening of the carb secondaries.
Drifting
Joined: Oct 2010
Posts: 1,972
Likes: 6
From: Chester Virginia
I don't know what exhaust the '75 had but my '76 had a 2-1-2 exhaust going through a huge old pellet cat. converter. When I put straight duals on, each with a ceramic grid bullet high flow cat converter and flowmasters the engine gained 750 rpm and 5-10mph more at the top end of each gear though I haven't tried fourth top yet. Part of it was the better breathing with more than double the exhaust outflow compared to factory and part of it was the elimination of the old crapped up pellet cat converter. Power now is "uniform" through each gear from start to finish and it wasn't before. I suspect you either have a rear end that isn't something like a 3:36 or your cat converter if it has one is crapped up. If so, modernize the cat converter to a modern high flow one if you want to keep stock systems and I bet you see performance improvement too. I sure did.
Instructor
Joined: Feb 2007
Posts: 216
Likes: 0
From: Lynchburg VA
