Header size for 427
Thread Starter
Instructor
Joined: Aug 2007
Posts: 144
Likes: 4
From: Chandler Arizona
Header size for 427
Hi everyone,
I am still getting parts for my build over the summer. The headers I have removed from the old 383 were headman headers with 1 5/8 primary and 3 inch collector.
The question I have is will the headers flow enough for a 427 that revs to 6k would I really see a difference going to 1 3/4?
If the old headers won't work what should I go with?
I am still getting parts for my build over the summer. The headers I have removed from the old 383 were headman headers with 1 5/8 primary and 3 inch collector.
The question I have is will the headers flow enough for a 427 that revs to 6k would I really see a difference going to 1 3/4?
If the old headers won't work what should I go with?
Le Mans Master
Joined: Sep 2013
Posts: 6,192
Likes: 750
From: near the thumb in the mitten
With an automatic and a street car probably OK, Stick, high stall, 4.10s IMO 1 3/4 or maybe larger. The cylinder head port size and camshaft profile have a lot to do with tube size and length. large ports big cam with lots of rpm normally require larger tubes.
Thread Starter
Instructor
Joined: Aug 2007
Posts: 144
Likes: 4
From: Chandler Arizona
The head ports are 220cc intake and 67cc exhaust
and this is the cam:
Hydraulic Roller
Duration @ .050'' Lift: 240° Intake / 248° Exhaust
Lift: .577'' Intake / .577'' Exhaust
Lobe Separation: 112°
Here is the engine specs
http://www.jegs.com/i/Blueprint+Engi...272CT/10002/-1
After doing research on my end, I am looking at hooker 2149 headers
http://www.summitracing.com/parts/ho...model/corvette
The only downside I see to them is needing a header flange gasket, any thoughts?
I can't seem to find 1 7/8 headers that would work for the C4 that have the AIR system.
Also how badly would keeping the 2.5 inch corsa cat back hurt performance?
Sorry about all the questions I want to make sure the car is planned and built right.
and this is the cam:
Hydraulic Roller
Duration @ .050'' Lift: 240° Intake / 248° Exhaust
Lift: .577'' Intake / .577'' Exhaust
Lobe Separation: 112°
Here is the engine specs
http://www.jegs.com/i/Blueprint+Engi...272CT/10002/-1
After doing research on my end, I am looking at hooker 2149 headers
http://www.summitracing.com/parts/ho...model/corvette
The only downside I see to them is needing a header flange gasket, any thoughts?
I can't seem to find 1 7/8 headers that would work for the C4 that have the AIR system.
Also how badly would keeping the 2.5 inch corsa cat back hurt performance?
Sorry about all the questions I want to make sure the car is planned and built right.
