My fuel system will -6an be Enough???
 

long story short I have a 3rd gen camaro with an LQ9 bored 30 over with flat top pistons Ls3 heads, BTR valve train and push rods and a sloppy stage 2 cam with an LSA supercharger, All will be mated to a T56 6speed trans. My power goals are 650 to 750+hp and I have a Walbro 450 in tank and I plan on ordering a set of 1000cc injectors but I'm not really sure on the fuel hose size I should run as a feed and a return. any experienced advice will help thanks.

https://www.lmengines.com/fuel-line-calculators/

With this flow and just a -6 an the speed of the fuel at the injector could be to fast if you don't split before the fuel rails and run them parallel.

8 feed PTFE. 6 is fine for return however going 8 feed 8 return is simpler because connections will always interchange and keeping spares on hand you know they will fit whatever line may need them.

thanks you for your input guys I really appreciate it!

-6 will easily cover 750hp.

But -8 will cover for almost anything in the future

And as above, it's handy to keep sizes the same rather than buying 2 of all different sizes.