First weekend out...loosing power.

[gasserx]

I ran at a 1/8 mile race this weekend (first time out with the fed).This track is an un-preped old airfield. 
Had a bad testrun on saturday, and nothing seemed to go our way. We found the problems and had at least 10 hours of wrenching and trying to find parts before we got to bed that day. On sunday mornings startup we seemed to have finally fixed everything and the engine sounded real good. Decided for a new testrun...
Engine felt great on the burnout, and also until a little bit over half way on the 1/8... then it startet to flat out and partially die. Kept it alive gently for a while, then it died just before i was about to pullover to the return. Timeslip: 6.9 and 98mph.

We got it back and checked everything, but could not find a reason. Went through ignition, nozzles/fuellines/pillholders..  Started it up in the pits a little bit later, and still sounded like a champ, so we decided to do another testrun. But same story again, everything good on burnout and halfway...then engine starts to flat out, then finally die just before pulling over, almost on the same spot.
350 sbc with Hilborn stack injection.

Any idea what this can be? I have a feeling the magneto is playing with us..

[BK]

Fuel tank venting issue? If you have foam in you fuel tank get rid of it.

[dreracecar]

The test for proper venting is to( empty tank) is to cap the outlet and to fill to the top with water and put the fill cab back on. Remove outlet cap and watch the fuel stream, if the colume is solid and without interuption the vents are fine, if the flow is intemitent  then the vent is either too small or blocked. most common issue of blockage is when a "pig tail" vent is used and not a "cork screw" style.
The best venting system for a dragster tank ( long and not tall) is by venting it front to back and a "T" in the middle (the direction of the "T" outlet is not critical) Under acceleration and the fuel rushes to the back, the tank vents from the front, and in deceleration vents from the back. Venting from the middle can be hit and miss when the tank is full on the burnout

[masracingtd1167]

A couple of things How big is your vent ? Your inlet hose should be no 12 . Check your inlet hose for kinks .i would think that if it was the mag it would show up at low rpm 's . What is your plug gap too much gap can cause issues . Check your barrel valve with a leakage tester at idle 18 to 20 percent should be a good place to start and also check leakage at full throttle to make sure it is not closing off .Keep us posted. Bill

[gasserx]

I will fix pigtail just in case. I use 12 line from tank to pump.
But i think maybe i have a mag with weights - i thought i had a fixed one, and we set it to 38...at what rpm would it reach max with weights?