question on phenolic spacers

I have a 1" Open Spacer under the 850 TQ on the 340 in my '74 Duster. Seems a little "hotter" on take off, and picked up some better throttle response. Butt-Dyno measurements :D 3.23's and 28x10-14" tires. I can burn the tires for a block (or until the next redlight, whichever comes first). I try not to though, 14" tires are getting hard to find.

and I've got a 1/2" Open Spacer on my '84 Dodge D50, with a 273 and a 800 TQ. Couldn't run a 1" because my filter almost rubs the hood at the moment. That baby will spin the tires like you wouldn't believe... 4.10's and 40x17-15" tires.