Originally posted by techinspector1
In my experience, cooler water temps (160*F) will reduce the tendency of the motor to spark knock, however this is a band-aid fix in my opinion. The most important aspect of engine building to preclude spark knock is the quench dimension (piston crown to cylinder head measurement at TDC). I've witnessed example after example of iron head street motors running at up to 11:1 on pump gas with tight (0.035"- 0.040") quench and cams with delayed intake closing points. With lightweight components and reasonable RPM limits, I think this dimension could be tightened up even further.

On that quench dimension, most chevy SB's are at a deck height of 9.025 - 9.035 in deck height, so allmost any piston sits down in the bore .o25 of an inch, then you have your compressed composition gasket at .o38. So therefor if you add .038+.025 you get a whopping .063 clearance between the top of the chamber and the piston top. So I am reasonig after maesurig the same piston rod assembly on all 4 corners of the block get your dimensions and if the clearances check out, deck the block down to 9.000 deck height and any piston top slightly proud of the deck, say up to .008 of an inch leaves .030 clearance and a little safety margin for eventual wear and piston rock. I figure that with the 462 heads with a chamber capacity of 64 cc's will give an approximate c.r. of 10.25 - 1 with a 350 + .030 (4.030 bore ). Okay so how much more can that quench dimension be closed up ?

Cams, I have degeed 3 different cams with different lifts and durations, and have made a note of what height the piston is ascending in the bore when the intake valve closes, it measures out that the more duration the cam has, the intake valve closes with the piston further up the bore, Now if the cam is advanced say 4 degrees the piston will be slightly lower in the bore when intake valve cloure occurs, this will of course have an effect on dynamic cylinder pressure. The other thing I have noticed is cam lobe seperation angle. The llarger the dispacement of your SBC the tighter you can run the CLS angle, for example 350 - 108 degres, 383 - 106 D, and a 400 say 104 D.

To get all this, it took a lot of internet reading and even more degree wheel turning with different cam duration and stroke combinations to understand the relationship between cam and compression ratios and where you want the power in the egine rev range.