Cam advice for more torque from 340

You have to:
1. Get the cam in and timed where you want it. Button up the front and put a bolt in the crank snout so you can turn it.
2. Put in one pair of lifters for one cylinder (with prelube on the lifter faces and lobes; I would recommend moly type cam lube):
3. Put on head in place, with a 1/4" thick layer of clay over the valve pockets on the piston, with the head gasket, and just lightly snug the head bolts
4. Assemble the rockers on that side for the 2 valves you are testing

Now rotate the engine slowly though 1 full cycle. If it wants to come to a hard stop, don't force it, but I don't think that will happen.

One tricky aspect: Assuming you have hydraulic lifters, then having the springs in place on the head will cause the the lifters to over compress if they are new and have no oil inside of them. The lifter piston will just compress down into the lifter body, and then the valves will not fully open so you have to find away to get some oil in the lifters so the lifter's internal pistons don't just compress down into the lifter body, but not too much oil so that they lock the lifter pistons in the full up position.

Or you take off the valve springs on that test cylinder and put in some light hardware store springs for the test, But if you don't have the tools to take the springs out, you can't do that.