I wouldnt call those practice for a 340/360 head because the ports are diff. Ssr is much more 'know how' than a 318 head.
You can hardly fk up a 318 head. Why i dont charge but 250.00 to make them go 200-210cfm w/stock 1.78 and 144 exh..the $600 dollar special for a full reman 'stock parts' and port job on a 318/273 set.
Just get the x heads and we can walk you through a safe approach to pick up the flow. Mine go
[email protected] intake and 199 exh