what is the best sized spacer for the non-rev'ed up motor?
 

Im intrested in Motrodize(sp) spacer. What is the best size.

5/16:)

Yah I talked to Tony recently before buying my 5/16" isothermal spacer. He told me that the 1/2" spacer produced more PEAK HP, but the 5/16" produced more area under the curve, which meant a more linear power gain. The latter is what I wanted, so I went with the 5/16". I got my kit from Performance Nissan. Andy and Kenny were pretty cool to talk to and I would recommend this place.

Study the plenum - plenum spacer shoot-out charts posted here. Then make a decision.

i studied and im still suck....

The 1/2 spacer makes more peak torque than the 5/16 spacer.
The 5/16 spacer makes more torque in the low and mid range.
So your decision is where do you want more punch?

then the question begs, do you even understand what you're studying?

if not, it might be a good idea to get some automotive knowledge before modding some more.

Can you use your engine cover with the 5/16" spacer?

yup. I did