Decided to replace all the hard lines and had a question around sizing. I checked all the usual sites to find the best deal and noticed Z-Car had both stock and upsized for the supply and returns. I ended up going with a direct buy from classic tube and Cliff is making me what I think are the upsized ones I saw on Z Car. Before I commit, checking in with the crew here to give me some final advice. I went with 3/8 for supply, 5/16 for return, 1/4 for vapor all in the OE plated look. I'm still running SU round top and a mechanical fuel pump but down the road looking to go with triples so that's why I figured I would upsize. How do these sizes sound and am I going to run into any trouble with my existing setup? Engine I am assuming is still stock from previous owner, just rebuilt nicely.

Oh and while I'm at it, advice on replacing them? My plan is to do all the hard lines for fuel, brake, clutch while I'm replacing the standard exhaust with headers and new pipes. Hoping I can wiggle my way through it all without removing much else of the undercarriage.

That's larger tubing than stock so you won't have any problems. Stock supply is 5/16 and on the 240's return is two pipe sizes smaller I believe. The 260's and 280's got a larger return that's one pipe size smaller than supply. My L28ET runs well with the stock 5/16" supply and 1/4" return.

Hard lines and electrical harnesses are the first things that go in when Z is put together. Fuel lines snake from very front to beyond the rear suspension. Portions of the rear suspension are not that difficult to get out of the way.

Edited 59 minutes ago59 min by cgsheen1

I hope you have access to a lift, if not get the car as high as you can and from previous experience have someone to assist. I have the same set on my car. They are close but far from perfect. It’s tight underneath there. Biggest problem I ran into was getting them past the undercarriage near the rear passenger wheel where they shoot straight up and over. It can be done obviously. Wish I had done it on a lift it would have made it a lot easier. Also it’s going to arrive in a tall box where you have to use a tubing tool to straighten out the long straight lines. They will come marked at each point of the run. Purchased mine on Amazon.

Edited 55 minutes ago55 min by Yarb