Hey guys! I have a holley 600 right now with vacuum secondaries. Single feed. Looking to go bigger possibly. Unfortunately I cant afford to test them all. I have read a ton of threads but havent found a build just like mine to make a choice. I apologize. I have a vortec 350 with a high rise dual plane intake, 2.02, 1.94 valves and valve job. Lt4 hotcam and long tube headers. Roller rockers as well. Making A little over 400hp. Th350 trans I'm looking either to go 670 or 750 for another carb. I'm looking at Holley 670 or Holley 750. I know holley may not be liked by all but I am a fan. Let me know what you guys think!