C2:67/300HP Holley- Staged Power Valve?

[Gerard F.]

I'm getting ready to put my replacement 3810 back together after replating the parts. The carb kit I ordered for a 3810, came with a staged power valve, which is different from the original single stage power valve in the 4743 block.

What difference in performance or ecomony would I get with the staged valve vs the single stage. As a geezer, I'm interested in economy in highway driving, but I still, on occasion, like to pass a Honda at 90.

Clem, are you there.

Jerry Fuccillo
#42179

[Clem Z.]

to quote the holley catalog

two stage PV ARE NOT RECOMMENDED for performance applications

[Gerard F.]

One more question

Clem,

I checked my Holley Carb Handbook and chucked the staged valve and put in a #65 power valve. I guess with the staged valve, it would run lean and hot, if I passed a Honda at 90.

But here's the other question- Check ball in the Secondary Thottle diaphragm or or not? The Handbook (for all and newer Holleys) indicates a check ball in the diaphragm housing and the kit includes one. The Holley Illustrated Parts and Specs Manual shows one in the diagram, but doesn't list a part number in the variable parts and specifications section for a 3810A. My 67 GM overhaul manual has no mention of a check ball in the vacuum secondary diaphragm housing.

So what gives. Was the check ball some later addition or modification?

Jerry Fuccillo
#42179

[Clem Z.]

Re: One more question

that i can not tell you for sure. most all of holleys aftermarket vacuum secondary performance carb come without the ball check valve. i would try it without it and see if you get a bog when the secondaries open and if you do and you have the correct spring install the ball.

[Wayne K.]

Re: C2:67/300HP Holley- Staged Power Valve?

Jerry,

3810, no check ball. Also to check if secondaries not only open but how far they open make a telltale out of a twistem. Wrap the twistem equal length around the drivers side of the secondary throttle shaft twisting it full length so that it is tight on the shaft but will slip as the shaft turns. Lay the twisted end on the throttle body (pointed to front of car). Manually open the primaries all the way and while holding them open manually open the secondaries.
You will see how the telltale works. If the secondaries open all the way the telltale will be straight up when the throttle shaft returns to the closed position. If not opening fully it will be somewhere between straight up and the starting position.

Wayne

[Clem Z.]

there is a easier way to tell wide open throttle

just put a small dab of grease on the throttle body where the secondary throttle linkage stop hits at WOT,make a pass and see if the grease has a mark in it. if not you have not reached WOT on the secondary and you need a lighter spring

[Wayne K.]

Re: there is a easier way to tell wide open thrott

Clem,

Your method works too but I came up with the twistem idea as it was easy to implement and told me how far and if at all the secondaries were opening. In my case I was only getting 1/2 benefit from the secondaries so I did change the spring as you have suggested. Besides, the little women made me clean my ears that day so I was low on grease.

[Gerard F.]

Thanks for the advice

Is there a color code to the spring. The book said purple, but I think they sent me green. I 'll have to take it apart again to check.

Also is there a way to bench test for flow and leaks on a holley.

Jerry Fuccillo
#42179

[Wayne K.]

Re: Thanks for the advice

Jerry,

The springs are color coded. The 3810 should have a purple one. I had to go to a lighter spring to get full opening on my L-79. I don't remember the color code range.

Wayne

[Clem Z.]

the holley catalog lists the RPM opening

for the different color springs with different engine size