To ensure optimal engine performance, all cylinders should have a minimum reading of 140 lbs per square inch (PSI) during a compression test. The variation between the highest and lowest readings among all cylinders should not exceed 15 PSI. A larger discrepancy indicates a potential problem that can lead to a rough idle and poor engine performance.
8:1.
A compression test.
4.000x3.750 with 8.5:1 compression
A compression test will determine which cylinder(s) are at fault.
There are a lot of variables when checking compression...basically the idea is to have all cylinders within 15 lbs of each other. Double check your readings.
the same way all modern combustion engines work with fuel ,compression, and ignition
Yes, they should fit ok. 305 heads should bump up the compression a little.
If the oil and water galleys match up, and it bolts to the block fine you should be good. You will probably get a very high compression ratio from this set up.. I had a small block .305 and I switched out the stock 64cc heads for a pair of 49cc heads I got a much higher compression and gain in hp. You really need to analyze the heads and block in question and surf the forums for a better answer.
The cylinder that you are checking must have the piston travel up and down 4 times are more.
Small block
It is a small block
It varies from 145 to 370, depending on a lot of variables including compression ratio, cam profile, and head design.