Here is a nice example of a 355cid SB with big heads that makes great power on pump gas.
And amazing power on nitrous.
Yes big heads work on 350's. The tunnel ram is simple, powerfull and way cool.
(do not use small CFM carbs) use 650+ holleys or 750 edelbrocks
Substitute the Lunati solid cam in the article for a similar duration solid roller cam and you are there.
(260in 268 ex @.050" 108LSA) will run very well on and off nitrous.
10:1 to 10.5:1 is just right.
Chevrolet Small Block - Engine Buildup - Tunnel Ram, Nitrous - Hot Rod