hi there sounds like you got the same problem i had when i got my l18 back it too has twin 45s and there back fired untill i put a holley blue fuel pump and regulator in and ran it on a dyno for a couple of hours,
the problem was that the starter jet were too big and the mains were too small this problem made it back fire shot fuel out of the webers.
i recken just change the jets and maybe the chokes too and you will be fine

Yeah cheaper optoin will be the pump worth a try.

I have always been told run a regulator. I dont know if this is myth or not, but I am yet to meet anyone saying that the needles in thier webers came off because of no regulator

I got one because i was told by Weber datto guru and others that it is needed. I just followed wise words.

i'm running with twin 40 webers and no regulator ... have no issues and haven't in the past ?? even on an old motor with with twin 40 dellortos had no issues without a regulator ?? when i had the current motor rebuilt and the original fuel pump put back on it had a severe over fueling problem, they couldn't come up with a reason for the pump doing it .... the guys tuning it fiddled around stuck on a new pump and no issue since ... the new pump's been run with twin su's and twin 40's, both on dynos with CO count and al the rest done .... no issues and running spot on ........ try a new pump maybe

I use a holley RED... its a 1-7psi ajustable regulator.

ok, ill get right on 2 the regulator this weekend, wats involved in hooking 1 up?, somebody give me an idea, . Its weird how its just started happeing.i wish the shop had just chucked the reg on in the first place. also wat sort of regulator do i need 2 buy, i was told the otehr day but forgot the name. thanks 4 all ya help guys, much appreciated.

IT should be fine.. I have known people with webers to run without Regulators for years and not throw the weber needles off. Its just to be safer than sorry, could be costly doing damage to the webers. Just dont Rev to high to much until you get the regulator. because the PSI off the Stock fuel pump works off the cam lobe more RPM more fuel pressure. I have heard the stock mech fuel pumps are good for 13psi.

Main problem i can see is the needle vavles overloading, float bowl over filling and causing a fire man, have you got another pump to try?

its the stock fuel pump, and no im not running a regulator, but i will be getting 1 this weekend. my main question is, will it be safe 2 drive , as i need the ute 2 morrow

Sounds like you must have always had a slight leak somewhere and now it sealed it has a 6-7psi pressure that it mite have been like the whole time with a leak. You have a regulator right?.. will just have to set it to 2 or 3psi

What fuel pump are you running?