The only issue with the 1.6’s on the exhaust is you’ll cut through the induction hardening of the casting and need to install exhaust seat inserts for unleaded fuel........ for what would amount to what I consider a very minimal gain in that combo.
No need for 1.6 exh on this one.
The 1.5 with a little work will flow 150 CFM
It's easier, less work to get 200cfm with a 1.78
This is a very mild build.imo cam will be done @4800 to 5000rpm, maybe.
With as cast heads it 'might' make 260-270 hp. It's not just the cam, that cam is actually good for about 300'ish in a 318 with some bowl work... or basically if it had heads that went 210cfm around .500 with the expected.100-.400 cfm flow up to that peak.
