I’m upgrading my fuel system and need to upsize my fuel lines to 3/8” all the way from the tank. I have an 83 gsl so the connectors are brazed to the tank. Is there a way to upsize these or should I keep searching for a gsl-se tank?

 

By upgrading what do you mean? Just a replacement of the old crusty line for a carburetor ? New fuel injection? I used a Holley in tank retrofit (12-136) with the Hydramat, which should help prevent starvation. Look it up the product is kinda cool if you are not familiar. Unfortunately the fuel pump is too small for my application, or so I have been told. If you are not running a turbo the 255L pump would likely be fine.

to plug the old lines I cut the excess off and tapped the holes and used stainless screws and sealed with a fuel safe epoxy. If I could weld or braise I would have. But Im certain I have it sealed well.

 

You could cut off the undersized fuel lines and braze in the appropriately sized ones. You can also drill the strainer basket to the larger 3/8" size. I've done this twice, with good results.

 

If you're making less than 400hp, the stock lines are sufficient.

If you're making over that, you should really consider a surge tank type system, because you really do not want to suck air in the fuel pump and even the GSL-SE tank will do that under some conditions. If you do this, as a bonus, the 8mm lines will be sufficient to feed the tank.

I don't think the GSL-SE tank will fit an '83. There are rear floor differences between '81-83 and '84-85, something with the spare tire or chassis longitudinals. I forget. But it sucked for me because I had a spare '85 tank and I had an '81 that needed a tank...