I am currently designing a fuel line system for my 91 firebird the stock lines are just rusted and junk. I’m not sure really at the moment if i am going to put in another TPI engine in the car or not. If I stay with TPI it will get a 350 to replace the 305 but i am leaning more toward a good 2nd hand ls, I really want the LS3 witch iirc is a 6.2L. Any ways back to my topic, I need help with i am not very how should I say it tech speech savvy when it comes to reading up on mechanics stuff. So will try to just ask what I need to know.

1. Steel or braided rubber hose i am not shooting for a lot of mods basicly staying with stock engines only changing what I have to for either one stated above, I imagine steel would be best but will the rubber flexible stuff work in the interest of saving money.

2. The stock fittings, Are the TPI and LS fittings the same or is there some sort of reference chart to look at with the different gm fittings.

3. The stock system has 4 lines supply return vapor and EVAP canister, I have seen ls swaps with only one line that’s got a tee off early in the line for the return can this type of setup with with both engines or would the TPI need both supply and return to the engine bay.

4. Cost I don’t want to dump 1000's in a fuel system so what pump's will work with both I assume the pressure regulator can adjust for high and low pressure.

I guess what i am getting at is I really need to build a low cost system that can work with either engine I want to install. I know that is a tall order that’s why i am asking people in the field please don’t think i am just an idiot thanks for looking.

 

You're not going to save money with braided rubber over steel line.

I used aluminum tubing for my swaps. Easy to form and flare, seals well compared to steel.

A tee return only works with a 4th gen LS tank swap because it has a relief valve in the return at the tank to control pressure to the engine. Another choice is to use an early LS Vette filter which has a regulator (relief valve) built into the return port of the filter. I've used both, not much advantage to the 4th gen tank other than the pump is up to the task. Takes more modification to run it than a Vette filter or another regulator.

You can use a return-type regulator that is adjustable up to 58 psi of the LS system. Costs more, but if you're fabricating the fuel lines anyway, you can use standard AN fittings up to the reg.

I'm using a Walbro 255 3rd gen in-tank replacement in my 3rd gen LS swap. Never had an issue with it since 2010. Others have used a TPI pump, which is fine with a stock LS assuming the pump is in good condition.

 

Ok thanks for the reply, now what size aluminum tubing is recommended for an ls fuel system. I looked and ya its a lot cheaper then the OEM kits.

 

Sorry, missed your last question. I just used 3/8" on my LS swaps, including one that produced 415 RWHP (which I switched to 1/2" when I switched it to E85 and swapped intakes - now makes 435 RWHP).