Well,

I went searching and found this on a Camaro site-

346236 1975-87 454 Open 113.0cc

2.06" Intake, 1.72" Exhaust

And, I found this on Roadsters.com:

346236 454 1975-1978 Open chamber ("peanut" ports)

Looks like they are not the best for performance-I'd see if I could find some 049's or 781's-