Topic: 69 BB exhaust size
in Forum: C3 Fuel, Emission Control, and Exhaust Systems
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Maybe a newbie question....but I am!
Why is it that my 427 goes from 2 1/2 inch down to 2 inch from the manifolds?
Why wouldn't they, (Chev), open the whole thing up and make it 2 1/2 inch all the way to the back? Heck...it's a big block!
Also, I have new front and intermediate pipes coming from Corvette Central. Looks like the originals were clamped. Should I use clamps or is it ok to weld them and still be okay with the NCRS folks?
Thanks
Kev
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Duncanville, TX - USA
Joined: 11/8/2003
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Vette(s): #1-1974 L-48 4spd Cp Med Red Metallic/Black deluxe int w/AC/tilt/tele./p/w-p/b/
Am-Fm/map light National/Regional/Chapter NCRS "Top Flight"
#2-1985 Bright Red/Carmine Cp.L-98/auto
Member: NCRS, NCRS Texas, Corvette Legends of Texas
Most, if not all, low HP engines used the 2" exhaust. The higher HP engines went with the 2 1/5" exhaust, but all engines had the 2 1/5" manifold outlets.
If you plan on doing NCRS Judging, it's best to use the same type of fastening as original. Without looking at the AIM, I couldn't say which way yours was originally, but it's safe to say that the head/intermediate pipes were most likely clamped. Some years had mufflers welded to the rear pipes, some were clamped....same with the exhaust extensions/outlets....some welded, some clamped.
Joel Adams
C3VR Lifetime Member #56 
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"Money can't buy happiness -- but somehow it's more comforting to cry in a CORVETTE than in a Kia"
60 mph
26" tire
2.73 rear end
=2100 rpm
http://www.angelfire.com/fl/procrastination/rear.html
A 3.55 rear end would get you 2800 rpm.
As you go up or down the rear end ratio list, each step adds or subtracts about 200 rpm.
|UPDATED|9/25/2013 9:50:05 AM (AZT)|/UPDATED|
26" tire
2.73 rear end
=2100 rpm
http://www.angelfire.com/fl/procrastination/rear.html
A 3.55 rear end would get you 2800 rpm.
As you go up or down the rear end ratio list, each step adds or subtracts about 200 rpm.
|UPDATED|9/25/2013 9:50:05 AM (AZT)|/UPDATED|
in Forum: C3 Fuel, Emission Control, and Exhaust Systems
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