[Zak]

Anyone has an idea if it's OK to raise the compression ratio from 10:1 to 10.5:1 in a naturally aspirated 347 cid small block that has an aluminum head, 30# injectors and sees only premium gas (even 98 octane most of the times)?

I also don't know how much should I set my initial ignition timing. I'll be using MSD ignition controller & HVC coil.

I wanna mill the deck .005" and the World Windsor Sr .005" (this should reduce the combustion chamber volume by 1 cc approx) and to use a thinner head gasket. I'll use a Fel-Pro of .038" compressed thickness instead of my current Cometic .045"

[chvyeter]

You'll have no problems unless you start getting around 12.1

[1slo5.0]

10:5:1 should be ok with 93 octane. Anything more will detonate and you might not here it but it will surely show up on a dyno graph.

[Zak]

Thanks for your info, guys..

After some thinking, I'll stick to my original 10:1 plan cuz if I wanna go to 10.5:1 I'll need to do a lot of machine work on the block deck, cylinder heads and intake manifolds.. perhaps need to notch pistons too.