Is this the correct book for small blocks?

The way I see it, a nice spring upgrade can be had @ Hughesengines which includes new retainers and locks for the stock valves. The heads are capable as we know through the MP create engine program to produce 400+ HP with a 230@050 Hyd roller cam. The 300/360 was a box stock engine that was given a 750, MP dual plane, 1-3/4 headers and MP’s electronic ignition system. This engine was known to produce just over 300hp.

So the OP needs to do nothing more than that above.
The purchase of new springs is a minor inexpensive amount and personally I’d never bother with all the LS swap for a driver/cruiser.

Should the owner want more power, new valve springs, retainers if needed and locks will replace the OEM material to suite the new cam. Even a small increase in duration will improve power very well. Let’s just use the MP purple cam, the “757” w/211@050 intake duration is at least a 10* jump in duration that will not have any side effects of a larger cam like the need of an improved torque converter, more gear or compression needed.

This cam will improve the RPM ability another 500 rpm without batting an eye and I’ll guess improve Tq. & HP by at least 10, maybe 15 hp.

He did state earlier that a big lumpy cam is not wanted nor is 400 hp. Just a driver and a cruiser. With Hwy gears he should be able to see 20 mpg. A great help in mileage and off the line performance would be a OD trans.

If you have been in or driven a stripped down 2000 Durango, they’re pretty good for a heavy truck. (That’s vs a cars weight.)
This is what I have pirated from my Daughter (and added the above parts, a RPM instead of an MP intake) after she wreck it. I use this engine in my ‘79 Magnum with a (currently) 727 & 3.55 gears rolling on Cooper Cobra, 245/60/15’s. An O.D. transmission will come later.