http://hamiltonfuelinjection.com/products/6-pressure-regulator-springs.aspx These are the commonly found springs. Hamilton is a reliable source from what I understand.

I would tend to agree with you, and you've convinced me to order the 18PSI spring as well. I'll start at that point and change to the 28 PSI spring only if needed.

You'll have to excuse my...

It is a bone stock L31 so the .414" Intake cam and I forget the exhaust lift, its in the .428" range I believe. RPM range at 70 MPH will be somewhere around 1900-2000 until I change gears out at a...

Here is what I'll be running.

Stock L31 GMPP Long Block
Edelbrock 7116 Performer RPM Intake Manifold
ACDelco EP341 Fuel Pump
Holley 670CFM throttle body w/stock 61# injectors with 28PSI...