I have a holley 600 VS. I recently got a spring kit for the secondarys and an advance curve kit for my distribtor. I changed the secondarys spring the other day and got the car running good. I put the advance curve kit in today, it gave me a ton of bottom end but the motor seemed like it was bogging and did not want to rev above 3000 RPM when driving. I went to a heavier spring in the carb and it helped but it still doesn't feel like it has any top end. I have had every spring in the carb from short yellow to black and none helped. I tried going lighter and heavier in the distributor and it didn't change a whole lot. Is this a problem caused by my timing or my carb.

 

WELL maybe BOTH, but my suggestion is work on ONE thing at a tiem get the timing sorted out (initial and total or "top-end") then work on the carb...

Also a 600VS seems a bit small to me on a 9.?:1 355 SBC, sure it will run and probalby have GREAT response but may be limited on the "screaming" top end by the CFM of the carb...

just my .02

 

Try to take off the air cleaner. And it might be caused by the timing advance. Not sure just a thought. Hope this might help.

 

I'll see if I can sort this stuff out tomorow. Orignally with the stock settings the motor pulled hard at higher rpms but was a bit of a dog on the low end. Thats why I got the spring kits to see if I could help this. I think it just needs some more fine tuning. I think most of the problem is with the timing. I did not want to play with it this weekend because I didnt have access to a timing light. Which I will have tomorow. I'll post how it turns out.

 

I got my timing set but I still have no top end. I am pretty sure my problem is in the secondary side of my carb. I used a paper clip to see if they were opening and they only opend about half way while driving. The motor pulls great till about 2800 rpm then has no power after that and doesn't want to rev any higher. I checked to see if the secondarys have fuel and they do. If I accelerate slowly it seems to do better. I am kind of puzzeled why this is happening. I tried with no air cleaner and it made no difference. I tried lighter springs and heavier springs none helped. I also tried removing the check ball to see if that made a difference and that also did not help. Does anyone have any ideas?

 

Your fuel pump may not be keeping up with the demand. Have you attempted to put a fuel pressure gauge on it? It should maintain about 4-6 psi at all times.

 

I don't have a feul pressure gauge but my fuel pump is a holley 60 gph pump.