I installed new 65pph injectors yesterday. Bumped timing 4 degrees. Fuel pressure at 7psi idle and 15 WOT with vAFPR. Removed vacuum delay valve from vacuum line for vAFPR. Noticeably more power now in all ranges.
My heavy truck likes these 65's more than the stock 55's.
Very pleased. SC

 

Super chevy:

Where did you get the injectors,what is the part #(GM), and how much were they. I am thinking of doing the same thing to my truck.

Thanks

 

I got them off eBay for $120 brand new in the boxes.
I think the part numbers were 17112493, colors were yellow/brown.
gmpartsdirect.com has them for $83 each.
SC

 

how do you measure the fuel pressure? Also, i know the stock FPR is not adjustable, but is it vacuum controlled?

 

You have to use a fuel pressure gauge. To do that, you need to buy one of the fuel pressure test kits at like Autozone or O'Reillys that are for tbi applications. I got mine at Autozone for I think $39. The kit has a "T" style adapter that you attach to the fuel line. Then you attach the gauge hose to the T and read fuel pressure at idle and WOT.
The stock fuel pressure regulator is not adjustable. You can make it that way, or buy an adjustable one from the aftermarket.
The best solution to fuel pressure adjustment in my opinion, though, is to use the vacuum adjustable fuel pressure regulator or vAFPR.
To find out where to buy and how to set up the vAFPR, do a search on it for the tbi board and read all the links, and buy a Haynes manual or similar for your vehicle that shows how to disassemble and reassemble the tbi and how to check fuel pressure, etc ,etc.
Hope this helps, SC