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Discussion Starter · #1 ·
It's no secret that our tri-five chevy's are notorious for giving fuel showers.

Correct me if I'm wrong, but it seems modern fuel pumps that pump unleaded gas expect the sort of back pressure only evident in modern filler neck configurations in order to know when to stop filling.

I've seen on this and many other vintage car forums the suggestion to weld or braze a modern filler tube that includes the unleaded fuel restrictor with the flap to the end of the old style filler neck and voila! it will work great. BUT... I haven't EVER seen one in action or heard that it works or even seen a picture of one. Should I assume that all those that have tried it were killed instantly??

I've heard that there were aftermarket products that were available at your oreilly/autozone/pep boys, but none of them do anymore. My mechanic described ones that looked like "ninja throwing stars" and I found this...

http://www.pciinc.com/index.php/gas/fill/pipe/restrictors/?osCsid=e7f3485af9d406dffe95019066c34750

Which looks a lot like what he describes... Anyone try one of these? Did it work?

Does putting a modern top on our tri-five stock filler neck eliminate spit-back because of the particular back-pressure characteristics of the unleaded restrictor? Has anyone out there actually done this and not been killed or otherwise embarrassed so much he couldn't talk about it?

I can't believe all of us are just going to accept that we will have to fill our fuel tanks "by ear". Someone must have done this - I'd love to see pictures.

Thanks in advance!!
 

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There have been other threads on this topic. I usually get a little "spill back" but very little as I have been filling this car forever, and I go real slow near the top.
 

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Trifive Automotive Electrical Wiring Expert
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A 57 has a vent tube to allow air to escape from the tank when filling, which helps on a 57. A 56 is probably the worse, with the long fill pipe and no vent. I had a 55 for 15 years and never had a problem filling the tank, since it has a short fill pipe.
 

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Fuel blow back at filler

In my 55 I installed a modern small hole filler top and non vented cap off a chev pick up . [2006 the wrecker guy told me ] I cut the top section off about 3inches down, just above the necked down area.The new neck at the top was the same size as the 55 at 2inches O.D.. I cut the stock neck to fit allowing for some wiggle room between the two to make sure I could get the right angle for the tank joint. . The top has a nice tab that can be adapted with a small extension to fit the stock angle at the body mnt tab in the 55. I joined the two pieces with 2 inch fuel hose and clamps. if you see a vent conn in the new pipe just at the necked down area this vent could easily be adapted to a vent set up in the filler cavity to ensure no blow back. I cut the vent port out as I installed an LS3 E ROD kit and put in the evap system and I needed a closed fuel system which contains a valve for expansion and suction . The modern non vent cap could be drilled for a vented situation if you don't install the vent line mod.. I do not have blow back now. but with the stock system it happened almost every time if I didn't pay attention. I hope this doesn't make this sound like a hassle because the neck mods were the easy part of the evap system installation. CHEERS TERRY
 

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Discussion Starter · #6 ·
batshannon, that sounds like the trick. I'll snoop around for a 2006 chevy pickup and see what I can find. Especially easy for me since I don't need the sealed tank for the evap system. I don't see why it wouldn't work. I'd just love to use the pump handle latch and top off my tank without having to listen to the fill and all the anxiety of spraying gas everywhere.

Thanks!
 
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