Vacuum Talk - The 1947 - Present Chevrolet & GMC Truck Message Board Network

MylilBowTie · 12-16-2003, 12:52 AM

I have 21in HG at idle (850rpm) on my vacuum gauge. If I pull the PCV all it does is lower the idle. It doesn't kill the engine or anything. I have a performer intake, and 1406 edelbrock carb. I messed with the mixture screws to get the 21in HG on the gauge. Shouldn't it die? Carb is not running rich, if anything it might be on the lean side. I can put my hand over the carb and it will die.

The pcv deal has got me confused. Its not just the pcv it also does this if the port behind the carb on the intake is open also.

**swervin ervin** · 12-16-2003, 12:58 AM

No. It will act just as you stated. Remember, it's sucking even when it's in the valve cover. If you can kill the engine when you cap your hand over the carb, you have no vacuum leaks. 21" of vacuum is great. I can tell very quickly, you have a stock cam.

I have to strain to get 15 or 16.

All the ports on the carb won't have vacuum at idle, some are what they call ported. This means they have vacuum above idle.

MylilBowTie · 12-16-2003, 01:12 AM

I used to have all the "hot rod" little goodies. But I have headed to a little more sensible side on the engine parts. I love the 270 magnum cam (13-14 in HG) I had but it was killing my gas mileage and transmission parts. So now I got a different regular performer intake, 1406, your LM1 cam and lifters (thank you), my hooker headers, and I kicked the th350 I had to the curb lol. I gotta th400 in it now and working on getting a driveshaft. The swap wasn't that bad but the driveshaft length and that hasnt been fun. So needless to say I still havent been able to drive it yet.

12-16-2003, 12:52 AM	#1
MylilBowTie Right turn Clyde Join Date: Nov 2002 Location: Cincinnati, Ohio Posts: 2,911	Vacuum Talk I have 21in HG at idle (850rpm) on my vacuum gauge. If I pull the PCV all it does is lower the idle. It doesn't kill the engine or anything. I have a performer intake, and 1406 edelbrock carb. I messed with the mixture screws to get the 21in HG on the gauge. Shouldn't it die? Carb is not running rich, if anything it might be on the lean side. I can put my hand over the carb and it will die. The pcv deal has got me confused. Its not just the pcv it also does this if the port behind the carb on the intake is open also. __________________ 1974 C25 LWB: 454 4bbl Carb / TH400 / 3.73 1992 Camaro RS 305 TBI

12-16-2003, 12:58 AM	#2
swervin ervin You get what you pay for Join Date: Dec 1999 Location: Cherryville, NC Posts: 4,798	No. It will act just as you stated. Remember, it's sucking even when it's in the valve cover. If you can kill the engine when you cap your hand over the carb, you have no vacuum leaks. 21" of vacuum is great. I can tell very quickly, you have a stock cam. I have to strain to get 15 or 16. All the ports on the carb won't have vacuum at idle, some are what they call ported. This means they have vacuum above idle. __________________ Mike 1985 Chevy C-10

12-16-2003, 01:12 AM	#3
MylilBowTie Right turn Clyde Join Date: Nov 2002 Location: Cincinnati, Ohio Posts: 2,911	I used to have all the "hot rod" little goodies. But I have headed to a little more sensible side on the engine parts. I love the 270 magnum cam (13-14 in HG) I had but it was killing my gas mileage and transmission parts. So now I got a different regular performer intake, 1406, your LM1 cam and lifters (thank you), my hooker headers, and I kicked the th350 I had to the curb lol. I gotta th400 in it now and working on getting a driveshaft. The swap wasn't that bad but the driveshaft length and that hasnt been fun. So needless to say I still havent been able to drive it yet. __________________ 1974 C25 LWB: 454 4bbl Carb / TH400 / 3.73 1992 Camaro RS 305 TBI



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