Head Explanation.....
Thread Starter
Melting Slicks
Joined: Feb 2006
Posts: 3,400
Likes: 3
From: Sarasota Florida
Head Explanation.....
Can someone give me an in depth explanation on what Stage 1, Stage2, Stage 2.5 and Stage 3 heads mean or what is the difference between them?
Thanks
Thanks
Tech Contributor
Joined: Apr 2007
Posts: 10,924
Likes: 78
From: Forney Texas
It depends on who's doing the work. It's become a buzzword really, but the higher you go in stages, the more is done to the heads. More port work, bigger valves, etc. You need to match the head to your performance desires. A heads/cam/headers 346 for instance won't like a totally hogged out port for instance. It will be very lazy but put up good high rpm #'s. Not much torque under the curve though. A smaller, higher velocity port however, will make excellent torque and have better all around performance for a 346, so choose wisely. 
Race Director
Joined: Oct 2002
Posts: 16,477
Likes: 26
From: Gone
CI 6-7-8-9-10 Veteran
St. Jude Donor '03
Typically...
Stg 1 = a simple porting job with stock sized valves.
Stg 2 = more porting + larger dia. valves
Stg 3 - more heavily ported, even larger valves, and usually optimized for a larger dia. cyl. bore.
Anything with a .5 is just marketing hype that for comparison sake can be rounded off to it's base number....but this nomenclature does vary by manufacturer.
Stg 1 = a simple porting job with stock sized valves.
Stg 2 = more porting + larger dia. valves
Stg 3 - more heavily ported, even larger valves, and usually optimized for a larger dia. cyl. bore.
Anything with a .5 is just marketing hype that for comparison sake can be rounded off to it's base number....but this nomenclature does vary by manufacturer.
