I read that the ideal compression for my 420a should be 9.6:1. So, when I buy pistons for my car, they should be 9.6:1, correct? Or is there a better set up for nitrous? I want to buy a zex kit and run the 55 shot on stock internals then by pistons and rods and run the 75 shot. Also can you do a bigger shot on the zex kits than a 75 shot? Thanx

its all in how well you tune it (air/fuel/spark)

If I were you I would stick with stock 9.6 or go with 10.5 compression with the 10.5 your gonna have atleast a better fuel pump. and will probably have to run mid-higer grade gasoline

If it was me and I was going to build my own motor I would use 10.5 or maybe even higher cause there is no sense in just building a stock motor again, Id go crazy }( muuhhhaaaaaa. id upgrade fuel system to more along the lines of a turbo car, (better/bigger fuel pump, larger injectors or the 8 injector setup with the extra 4 kicking on with a big shot of nitrous }(

ok the higher the compression, the better for nitrous right? Ok, I am not that good about internal motor stuff again. As for the fuel syste,, I plan on upgrading the pump, injectors, rail, get a adjustable fpr and maybe a safc. So, 10.5:1 would be better? Thanx, another other suggestions or tips guys?

how much of a shot are you going to be running?
if above 150 shot might want to ceramic coat the pistons to be safe
10.5:1 would be optimal

you should get a EGT and a/f guage to monitor the system and use a wet system

i have a fuel rail that has a port on it for fuel to a nitrous system. might be nice for ya to have.

Bill