Fuel Line Sizing

[86Cutlass383SR]

First I'd like to say I have done some searching on this and didn't quite find an application simular enough to mine to get a definative answer. Most are running a lot more HP than I'll ever be at.

Hopefully this weekend I'll start getting my tank in the 86 Cutlass swapped out and get some fuel lines ran. I'm running a 4.3l Monte Carlo baffled tank setup with a Cutlass neck and the stock 4.3 in-tank pump replaced with a 255 Walbro f-body pump. Stock lines sizes are 3/8" main, 5/16" return, and 1/4" vent.

My injection unit is a stock-type 89 TPI with Accel SuperRam plenum/runners and the matching Accel base. 30# SVO injectors and a Holley adj press regulator will be added. The stock sized lines for the TPI will be retained.

The engine all this will be hooked to will be a 383 for mainly daily driving and of course some *spirited* playing. Estimated engine output will be slightly under the 500hp/500 tq (flywheel) range. No nitrous or power adder will be run.

Now for my question. Since I'm completely replacing the main, return, and vent lines in this car should I install the stock size 3/8", 5/16", 1/4" lines or move up to 3/8" for both the main and return? I'd like to just do this once and not have to worry about sizing and pressure issues later.

Thanks

[86Cutlass383SR]

Anybody? At what horsepower point should you start increasing line sizes?

[MCMLXIX]

Doug,
Check out this thread...

https://www.pro-touring.com/forum/sh...fuel+line+size

[86Cutlass383SR]

While doing my searches, I did come across that thread. I read it and read it. On one hand I kinda grasp the concept of what they're talking about but it still makes my head

That is the reason I ask this quetion hoping I could get a simpler, non-technical answer. I'm not an engineer. I was kinda hoping I could get something along the lines of: With an estimated 500 hp/tq you could run xxx main and yyy return and be just fine... or something like: with 500 hp/tq you really need to run xxx for both main and return...

No flames intended for anyone. It's just that some of us out here can't wrap my/our head around flow dynamics, etc. We need simple answers to some questions. I am one of those guys.

I guess my question was just too simple. And they always said the stupid question was the one that wasn't asked... sorry