I made this post on the Turbo Forums in 2006:
"A turbo kit company in Washington State offered a boost activated power valve with the only modification to the valve being they removed the spring from the normal location (by cutting the coils and pulling them off the valve, not turning the brass threaded adjuster). This power valve was new.
They then made a simple bracket that attached to the jets where the jets screwed in to the metering block.
They then took a second used power valve and unscrewed the brass threaded adjuster, removed the power valve spring and mounted the spring so that the spring pressure kept the power valve closed normally. When under boost pressure in the power valve cavity pushed the Power valve open against the used spring pressure/ bracket resistance. Tuning the opening point was easy as the used power valves come in lots of sizes 2.5",3.5", 4.5" etc, all the way to a 12.5" PV.
Very simple really."
A reply by one of the Turbo Forum Members:
"Ha, ha, ha. That is exactly what I came up with but totally without the knowledge of this company that you spoke of. I did make a bracket that was bolted down using the regular jets and it also had a small boss that I just tacked on so that the spring from the PV would be centered on the brass head of the regular PV and as you mentioned, just take off the regular spring on a regular PV. This is effective to some degree but with the pressures in the carb bowl and in the PV well, it equalizes too good that the valve doesn't open as far as it is desired to. I now have a metering block that has a channel in it that is boost referencing to the PV in the well but I also am blocking off that little boost hole in the carb body so that there is absolutely no vaccum at all, just boost. Also if you look at a 650/750 carb body, there's enough meat so that you can actually drill and install a tube there to boost reference the PV that way too but using the metering block is/was easier."
So as mentioned earlier there has been much effort on trying to get the fuel curve correct and adding the fuel at the right time to a Holley carb.
I will post up a couple of simple PV Bracket Puctures (to hold the Power Valve shut) and then a link to an old Hot Rod Article that used Kevin from CSU's Carb and how his Blow Thru carb was assembled to make 1000 hp.
Here is the link to the article.
http://www.hotrod.com/articles/watch...wer-blow-carb/
That being said, I was at a Dyno session at Steve Morris Dyno, (they were doing a carb shoot-out) on a BB Chevy and saw both the CSU Guy (Kevin) and his CSU Carb and the C&S Guy (Roger's) Blow-thru carb make over 2000 HP during testing.
Tom V.
ps For a while years ago Kevin (from CSU) was posting on the PY Board.
Tom V.