I have an older holley/racing beat intake system for my street ported 4port 13B. I noticed in the new racing beat catalog they are now selling the same kit with a holley 600 carb. So I picked up a old used holley 600 #1850 your standard square bore vacuum secondaries carb. Question #1 My holley 550 has #61 in the primaries. Should I use a bigger fuel jet with the 600? Anyone tore apart their new R.B holley 600 and noticed what size jets they come with. Also I'am going to buy all my rebuild parts through Summit, and I noticed in their catalog you can spec out different vacuum sizes on the power valve. Guessing lower vacuum number translate into quicker opening secondary jets. Does anyone have any experience on this or should I just use the one that comes in the rebuild kit. I think that one would be more calibrated for a V-8. Rx7 Carl I hope you read this, as you seem to know just about everything on carbs. Thanks

 

Making a holley work out of the box wont be easy. Just look at how many threads on the subject there are. Since you have a RB 550, you have the opportunity to reverse engineer it so you can make your 600 work. Truthfully, I dont think your gonna see much of an improvement except at hi rpms going from 550 to 600. But anyway, the powervalve is set to open at a specific vacuum, use what RB used in your 550. The number is right on it. As an idea, why not just swap out the center sections of the carbs? Then work on tuning it.