2003 ZO6 Corvette
Thread Starter
Heel & Toe
Joined: Aug 2015
Posts: 24
Likes: 0
From: Carmel Valley CA
2003 ZO6 Corvette
As I am a new member, but not new to owning Corvettes, I'd like to ask if anyone done any performance work that meets California Emission and what did you do??
Thanks Joel
Thanks Joel
Melting Slicks
Joined: Nov 2008
Posts: 2,185
Likes: 641
From: Garland TX
If you are wanting to do headers then you are pretty much stuck doing shortys. Did BBK shortys on mine and I don't care what anyone on this forum says. There is a huge night and day difference.
Le Mans Master
Joined: Aug 2005
Posts: 5,375
Likes: 328
From: CA.
St. Jude Donor '13-'14-'15
Yes depends on your goals and car's use----
Most all SC and turbo kits are all Calif CARB legal these days--With minimal street boost like 6 PSI you can net another 100 RWHP---
Long tubes are illegal period in calif-- so shortys are the only option
LT's can net another 20-25 RWHP as shortys only about 10-15 RWHP
NOW if you don't want to go the boosted route then you are left with cam/hds modding
To pass calif smog a cam has to be as such---No more than .225 in duration at .050
lift doesn't matter and an LSA no smaller than a 114---Typically these cams will still net like 35-40 RWHP----add better heads maybe 15-20 RWHP--shortys like 15 RWHP
so you end up with an added 75 RWHP instead of the 100 using boost but for about 1/2 the cost---
Most all SC and turbo kits are all Calif CARB legal these days--With minimal street boost like 6 PSI you can net another 100 RWHP---
Long tubes are illegal period in calif-- so shortys are the only option
LT's can net another 20-25 RWHP as shortys only about 10-15 RWHP
NOW if you don't want to go the boosted route then you are left with cam/hds modding
To pass calif smog a cam has to be as such---No more than .225 in duration at .050
lift doesn't matter and an LSA no smaller than a 114---Typically these cams will still net like 35-40 RWHP----add better heads maybe 15-20 RWHP--shortys like 15 RWHP
so you end up with an added 75 RWHP instead of the 100 using boost but for about 1/2 the cost---
Acct Suspended APR 2026 by request
Joined: Dec 2010
Posts: 10,367
Likes: 1,272
2020 Corvette of the Year Finalist (performance mods)
C5 of Year Winner (performance mods) 2019
but you are stuck with that 75hp, with a blower you can add a whole lot more if you wanted to... at times I wish I was one of those guys who could add an intake and exhaust and call it quits but unfortunately I'm not wired that way... my z still had me snoring in the low 400 range and a blower woke my car up... but it boils down to how much power you really want and the op will know himself better than any of us so he can make that call
Thread Starter
Heel & Toe
Joined: Aug 2015
Posts: 24
Likes: 0
From: Carmel Valley CA
Upgrades 2003 ZO6
Thank you all very much for your comments. It was very helpful and leads me to make a few choices on upgrades for my car. I've always liked and worked on cars from my high school days to know at age 67.
I also have a fully restored 1965 Mustang Convertible, which now has a 351 Windsor engine and a 5 speed Tremic. Thanks again for all your input
I also have a fully restored 1965 Mustang Convertible, which now has a 351 Windsor engine and a 5 speed Tremic. Thanks again for all your input
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