Valve rattle?Detnation?Spark blowout?Bad gas?

[91lxcoupe]

I got a problem. When my car gets in the higher rpms, I hear what sounds like valve rattle or something. The valve rattle noise wasn't there when my car was n/a a month ago and started when I added the blower. I thought it was spark blowout so I installed a HI-6 and LX92 coil today. I had a HI-6S and PS91 at first. I thought this would fix it but its still doing it. I'm running 93 octane gas, Autolite 3923's gapped at .030, HI-6 ignition box and LX92 coil, 11 degrees timing and the chip is controlling the rest, SCT tune which I'm not fully satisfied about. Anyone else had this problem or any advice on pin pointing the problem. My tuner is in New Orleans so it may be a while before I can back to him.
Thanks

[MikeyMustang]

Try adding some race gas like unleaded 104 and see if the "rattle" goes away....if so you might want to back down the timming some more or get it retunned

Mike

[91lxcoupe]

Thanks Mike for the reply. I'll give it a try if I can find some.

[speedytang]

Detonation for sure. Now the question is what was the total timing at wot with boost using the chip. Chips are really not the best setup with boost because it has no boost reference. I would remove the chip if you using bigger injectors or a fmu and set the timing at 19 degrees with the timing jumper on the distributor removed and give it a try.