Do you have a bare block that you can use for mockup?
It really helps if you can use a bare block. You would need a pipe or tube that fits snugly on the pump shaft. Make some bushings to center the pipe in the front and rear mains.
You will want to have the oil pan, THAT YOU INTEND ON RUNNING, installed on the block. Since you are using a 4-point mount, install it (and timing cover) on the blocck.
The pump shaft drives the location of the engine, NOT the stringers. If you are using a standard 1310 driveshaft, the engine should be 8-13/16" from the snap ring on the front of the pump shaft to the crankshaft flange. If you are running a flywheel instead of a flexplate, account for the additional thickness. Without shortening the driveshaft, you can be slightly further forward, but no further back. Ideally, you want 1/8" to 3/16" clearance between the snapring, on the front of the pump shaft, and the end of the driveshaft slip yoke.
Ideally, the pump should be centered in the hull. Locate the engine block left-to-right, on the pipe, between the pump shaft and the tip of the bow.
Level the engine side-to-side relative to the gunwales. The stringers are never straight or even. Don't bother trying to locate off the stringers. You want the engine to appear straight and level when looking at the boat as a whole.
The height of the block is primarily driven by angle of the pump shaft. Try to keep the main journals inline with the pump shaft. If you have interference between the oil pan and the front 6 bolts of the jet intake, raise the entire engine slightly, so that the pump shaft and main journals are still parallel. If you the engine looks like it is at an extreme angle where it might affect the floats in the carburetor, you can drop the front of the engine 1 to 1-1/2 degrees to help level the carburetor. Be mindful that this doesn't create excessive angle at the crankshaft. As the front of the engine rotates down, the crankshaft flange goes up.
Once you have the block where you want it, adjust the feet of the 4-point mount to meet the stringers. Look everything over three or four times. I always like to have a second set of eyes check my setup before making it forever. Take care drilling through the stringers.
Post pictures and ask questions if you are confused about anything.
Cheers,
Joe