Does anyone have an idea of how much compression I can run in a 355 4bolt sbc if I choose to use nitrous. I'd only be looking for about a 100-150 shot on top of a 10.5:1 500 hp engine w/an HSR. Is that safe?

 

You will be fine with aluminum heads. and pump gas just pull some timing out and step the plugs down a heat range or even two steps down make sure you have good fuel pressure and dont run extended tip plugs also gap them .035 to .030.And to answer your ? I have seen 15-1 motors running two fogger set ups.

 

i dont have an exact answer but i have been using nitrous for awhile now and with what you have i prolly wouldnt go any higher then 11:1 but i believe you should be ok and safe to run up to a 12:1 ratio

 

Im actually running GMPP Iron heads (I guess the paint job worked). Do you think thatd still be ok? Thanks for the quick responses.

 

yeah i still think you should be fine. just private message me if you have any other questions about setting up your nitrous.

 

ok. Thanks a lot.

 

no problem bro, have fun but be safe

 

Whatever you can get away with NA with _NO_ detonation should be OK with spray

 

You'll be using what, 94 octane NA then? 10.5:1 on iron heads?
Then you probably want race fuel with the spray.

 

With iron heads you will be at the raged edge. I would mix or do as I have done in the past put in a seperate fuel system for the nitrous and run good fuel when you spray it.