Horse power guess

ir3333 said
stock '73 340 has better heads,more cubes and bigger cam and was about 240 hp
you may be in that ballpark.

But 73 would be net hp
I seems when people talk about modified engines it's in terms of gross hp.

I'd say depends on your ported heads. I'll give around 300 hp @ 5000 and 380 lbs-ft @ 3500