My .02...
the 4 bolt issue, it is my understanding that the 4 bolt blocks were only on the "boss 351". They didnt have them in 70.
The blocks are the same, just not drilled/tapped.
If its a 4v 70' it should be the "M" code 300hp motor. (that is what mine is)
For oiling, run a line from the oil pressure sending unit port just above the filter around to the oil pressure sending unit port above the rear main.
If you are going to run a mechanical cam then you can use the moroso oil restrictors, but DO NOT use them with a hydraulic cam.
IMHO the best intake made for the cleveland is WITHOUT question (for a street car) the Blue Thunder intake. Its spendy, but it is to a Cleveland, what the performer rpm is to the mouse motor.
The weak point in the C' for turning rpms is the Intake valves. The stockers were two piece, if you turn em hard, the head breaks off and gets swallowed. BOOM! Buy some manleys, or millodons, or whoever you trust, and forget about it.... she'll spin 7K ALL DAY LONG and be happy.
The weak point of the breathing is the HORRIBLE short side radius of the exhaust ports. This can be helped by MPG Head Service "port plates", or by filling the bottom of the bort with brass, or by getting a good exhaust biased cam like the Lunati "Bracket Master". Get a good, no, I mean good! exhaust system, nice headers, x-pipe, and some low backpressure mufflers and this will also help. Don't skimp here, it's just not worth it.
Just my ops.... not fact, just what I feel to be true. Hope it helps.
Dave-