Posted similar question to another board and got the below feedback. Does this jive with the gospel of Techinspector and Denny? i've been reading and searching and reading some more. Looking for closure on this. Help!!


""OK. With an IVC of 66 and the above specs:

SCR-9.62
DCR-7.62
Dynamic cranking pressure: 149 psi

Should be fine running 87 octane. Just be sure the IVC is in fact 66.

I used a quench of .04 (.01 deck, .030 gasket).

SCR by itself does not mean anything. DCR is calculated by using the intake valve closing point. The earlier the intake valve closes on the compression stroke of the engine, the more air gets compressed so you have a higher DCR.

Smaller cams will close the intake valve earlier and larger cams will close the intake valve later. Had you used a bigger cam with a larger IVC your DCR would be below 7.5 and you would need to increase your SCR to get it above 7.5. That's why I said SCR by itself does not mean anything.

Your DCR should be between 7.5 and 8.5. Yours is at 7.62 which is at the bottom of the recommended range. The higher you go with your DCR the higher the octane must be.""