how much does a throttle body spacer help? and how much will the port and polish help? what sort of gains? on a 2.2ohv cavalier. cause i want to see if it will help out as much as i think it will before i do it.

10.5 second 1/8mile
est hp=130
est tq=135

Won't help out Much esp. on a OHV engine- As for a Port and Polish done right with supporting mods you could see good gains over stock-

TB spacer does nothing! Do the port-and-polish; let your engine breath freely!

I don't think a throttle body spacer gives that much of a performance gain. Port and polish the cylinder head and using a larger throttle body would be a better choice. Leave the intake ports somewhat rough for fuel atomization (120 grit cartridge rolls), but make the exhast ports from the underside of the valve past the valve guide to the exhaust port opening smooth (220/320 grit cartridge rolls). Don't go past the valve guide area on the intake valves. Radius the sharp corners on the cylinder head to eliminate stress risers. You might want to radius the oil passages inside the cylinder head as well. You could also CC the combustion chambers for equal volume if you want to get that critical. Don't forget the valve job (at least a 3 angle valve job, but a 5 angle one is even better) to take advantage of your hard work/investment in porting/polishing the cylinder head.