HELP!!! Starting problems

[ntmaster]

I am pulling my hair out here people, need help getting this running.
Ok here goes, just rebuilt the top end on 1971 911T. Reset cam timing to 2.5mm, valve adjustments to .010mm. Installed new points, cap, rotor, wires and plugs. Rebuilt both Zenith carbs and set air-fuel needles to 2.5 turns. Has new fuel filters in tank and before carbs. Fuel pump is at 5psi and flow is 1qt. in 15 seconds. Have spark at coil and and plug wires ends. Cylinders compression are 125psi to 135psi.
Am I missing something, its seems to want to start for about 3-5 secs and then dies. It won't stay running. It did run just before I tore it down for the rebuild.
Any and all help will be much appreciated.

[Lapkritis]

Do you have a fuel pressure gauge on the carbs that you can watch when it stalls?

[ntmaster]

I can install one, just have to add a T-barb to connect it.

[Lapkritis]

That's a good place to start. Fire, fuel, air and timing. Sounds like you have confirmed all but fuel. Might be simple matter of fuel pump quitting while running but not cranking... relay.

[ntmaster]

will give it a shot tomorrow and post results. Thx

[K Sykes]

One other possibility. Could your distributor be off by a tooth? I had mine off by one tooth and had similar symptoms..

[ntmaster]

Did the tests on the CDI and fuel pump, they turned out to be fine. While testing the fuel pump, pulled the line and checked for flow and let it go into number 2 cylinders carb. Tried starting again after putting everything back together and fuel shot out of carb, which told me timing issue.
Doh, When I took apart the engine I separated the parts left and right side. Seems while cleaning up the bench the cams were moved. I unknowningly installed the cams on the wrong sides. Was able to remove the cams while engine was still in car and swapped them, got it all back together and to no surprise it started. So a word to all those rebuilding, never trust that your parts will remain in the same place you put them. Check your part numbers before installing them. Lesson learned. Thanks to all that responsed, helped me in diagnosing the problem.