I lived in the SF Bay Area until I was 29, then moved to Wyoming where there is no smog check. I thought if you run a diesel in California you had to have a state certified shop verify that it was a diesel because people were reporting their vehicles as diesel fueled so they could (illegally) avoid smog check and register their cars with modified gas engines that wouldn't pass smog. Or is Fresno area not a smog check area?
To put my two cents in: I'd say go with the 454. Keep it simple and easy. I have a 454 in my square that was desmogged before I got it. I run the SM465 and 4.10 gears. Its all stock except for an Edelbrock AVS2 650 cfm carb and open element air cleaner. Runs great, lots of power even for being wore out and I suspect it has burnt valves. The SM465 is not a fast shifting tranny, so don't expect to be doing speed shifts, but there is a trade off. It is a tough tranny and considered bullet proof. With 4.10 gears and stock tire sizes I'm usually in top gear around 25 MPH unless I'm under load. Once I'm in top gear I can floor it and the secondaries open up it really takes off. Hauls ass for an old beater truck.