340 with 302 cast head for pickup

I know about the crap gas and the high compression we had the same bottom end in our 68 dart with ported X heads milled 90 thao with a solid lift mopar performance cam and crane 1.7 roller rockers. It thundered and moved real good but a little to much for this truck. I told him about adding bigger valves to the 318 heads when we were having them done because that's what I was going to do with them and build a 318 and put them in my 88 dakoda. I was going to use a least the 360 valves 188 or 196 's I think but I got nowhere and he was paying.
It going to have built 904

It not going to be driven everyday but probably often. He not really worried about fuel milage because he has a bmw motorcycle that he rides almost every day.

Do you know what compression it would be I'm thinking like 11.5 to 1 I will post up more when I'm not on my phone