[wmhjr]

Originally Posted by Rokker

Clill, it´s hard to say. I´ve had some small signs of it happening but never as much as this, never just dying on me. Except for one time I was street racing with a friend, I had a a/f gauge at the time and it was def leaning out.
Filled up the tank, and it was good.

My tank ventilation consists of a 2mm drilled hole in the cap. For some reason the old one was blocked so I just cut it off. I´ve been thinking I should drill and tap a hole for a barb hose connection in the filler tube.
What would be sufficient ? wil -10an be enough ?

I know I seem like an idiot posting this, but it´s better to be honest and get help than faking how fantastic my car is. I´m not really this stupid
but the car has so many issues to take care of, and is an ongoing project with taking one step at the time. The fuel system have for the street worked ok. I don´t like fixing stuff that isn´t broken. Now it is "broken" and it´s time to fix this for good, and never look back.

I appreciate the help guys, and steer me right if I´m being stubborn on stuff:-) I like to think I´m Frank Sinatra sometimes and do it my way.

First, I'll try not to comment on the "street racing".....

I wouldn't be too crazy about just a 2mm hole drilled in your cap for vent. Remember that from the factory, the OEM type barb was much larger than that and it was for cars with very small diameter fuel supply and relatively small demands as compared to what you need. So, it sounds marginal even with a much less demanding motor. With what you have, a 2mm hole is probably not even close to being enough. If you're going to end up sumping your tank (which again, I would probably not do if I were you - the replacement sending unit provides some additional advantages) then I would also at a minimum put a decent sized connection on your tank for vent. To me, the better option if you're going to keep that tank would be to just get the darned replacement sender/pickup, which will have both feed and return/vent connections on it. That being said, you don't need anywhere near -10AN for vent. -4 or -6 would be perfectly fine.

That being said, I'm not sure if you can really attribute the issue to lack of sufficient vent, only because if that were the case the problem ought to be a bit worse with the tank pretty well full rather than pretty well empty. The lower the fuel level in the tank, the more vapor volume as opposed to fuel volume and the less impact I would think vent would have just as a guess. I could be completely wrong though. And no matter what, the vent issue should be corrected anyway.