timing question

[fryedaddy]

i have a bbm headed 428 close to 11-1,.245 at 50 flat tappet,etc. question i may have asked before because i can be forgetful. i have my timing set at 33 as suggested buy the forum.i just filled up on 110 fuel.for max performance would i leave the timing alone or add or take away? or is there no relationship between octane and timing.

[plovett]

Do you have a way to measure the results?  ET or something else? Butt dyno?

My guess is that your are fine. I would still experiment in small increments, like +/- 2 degrees if you can measure the results in any way at all.  I think most of the time for most situations the optimum total ignition timing is fairly constant for a cylinder head.  Most people will say that for a given cylinder head the total ignition timing will not change much.  I have seen anomalous results, though.  I think low compression and high octane favors more ignition timing.  Since you have 11:1 compression I doubt your optimum timing will be off much from the norm.

For example, I once had a low compression (9.3:1)  FE with Edelbrock heads and race gas (I don't remember the octane) on the dyno.  It liked a lot of total timing.  Usually Edelbrocks like 37-38 degrees.   We went to 41 and even 45 degrees and gained power before I said whoa.   

BBM guys can take over now.

pl

[Faron]

Ive  done a few Dists for Blair Patrick and he has NEVER asked for more than 36 total on BBM Heads , as long as your certain your timing marks are Correct ( Ati's are of 7 degrees ) id try bumping to 36 , but doubt more will help BUT , a few extra and more octane than a combo needs can sometimes want MORE Total