vac line question - The 1947 - Present Chevrolet & GMC Truck Message Board Network

76bonanza · 10-10-2005, 05:37 PM

Right now my vaccum lines are as follows rear of manifold fitting with two nipples one going to tranny (th400) one capped. Off back of carb(holly 3310) A tee one going to power brakes one to pcv. Question can I move the pcv to the other one coming off manifold? Remove the tee and run brakes straight of carb?

Thanks

cableguy0 · 10-10-2005, 06:26 PM

the brakes and pcv should not be teed off together in any case. the 3310 only has 1 large vac port on it. what i ended up doing to solve the problem was to get a 4 hole 1 inch spacer with a vac fitting in the back of it to the booster and the fitting on the carb for the pcv

76bonanza · 10-10-2005, 06:45 PM

But can I run the pcv on the manifold fitting?

cableguy0 · 10-10-2005, 06:49 PM

you could always swap the 2 post fitting for a single outlet fitting with a bigger nipple on it. the pcv hose needs to be the size it is. too small and it wont work like it should. as long as you can accomidate the hose size you will be fine. you would be better off however running the brake booster off of the fitting in the manifold and the pcv on the carb. the carb will more evenly distribute the crankcase gases so that not one cylinder gets loaded down

bejay · 10-11-2005, 06:39 AM

the pcv is a controlled vacum leak, if you put it on the rear manifold fitting it will lean out number 8 cylinder to the point it will not even hit at low idle speeds that is why it should be hooked to the carb.
hooking your brake booster to the rear manifold fitting would be your best option and would provide more vacum to the booster than the way its installed now teed in with pcv valve.

**truckdude239** · 10-11-2005, 08:50 AM

wow i glad i looked at this because my pvc is hooked to the manifold lol was like that when i got the truck

76bonanza · 10-11-2005, 07:11 PM

ok so best set up is tranny and brakes off intake and pcv off carb. the fitting that screws into the intake were can you find those? I never see them for sale anywere looking for some different ones.

Thanks

10-10-2005, 05:37 PM	#1
76bonanza Senior Member Join Date: Mar 2003 Location: St robert Mo Posts: 2,001	vac line question Right now my vaccum lines are as follows rear of manifold fitting with two nipples one going to tranny (th400) one capped. Off back of carb(holly 3310) A tee one going to power brakes one to pcv. Question can I move the pcv to the other one coming off manifold? Remove the tee and run brakes straight of carb? Thanks __________________ 1968 c10 lowered 3" 4" 355/Th400 built by Hatfield racing in joplin MO

10-10-2005, 06:26 PM	#2
cableguy0 Senior Member Join Date: Apr 2000 Location: Delta,Pa Posts: 14,950	the brakes and pcv should not be teed off together in any case. the 3310 only has 1 large vac port on it. what i ended up doing to solve the problem was to get a 4 hole 1 inch spacer with a vac fitting in the back of it to the booster and the fitting on the carb for the pcv __________________ Owner of North Point Car Care in Dundalk Md. We specialize in custom exhaust on both modern and classic vehicles. We are a full service auto shop from classics to modern vehicles. Feel free to contact me with questions. I will give a 10% discount to any board member.

10-10-2005, 06:45 PM	#3
76bonanza Senior Member Join Date: Mar 2003 Location: St robert Mo Posts: 2,001	But can I run the pcv on the manifold fitting? __________________ 1968 c10 lowered 3" 4" 355/Th400 built by Hatfield racing in joplin MO

10-10-2005, 06:49 PM	#4
cableguy0 Senior Member Join Date: Apr 2000 Location: Delta,Pa Posts: 14,950	you could always swap the 2 post fitting for a single outlet fitting with a bigger nipple on it. the pcv hose needs to be the size it is. too small and it wont work like it should. as long as you can accomidate the hose size you will be fine. you would be better off however running the brake booster off of the fitting in the manifold and the pcv on the carb. the carb will more evenly distribute the crankcase gases so that not one cylinder gets loaded down __________________ Owner of North Point Car Care in Dundalk Md. We specialize in custom exhaust on both modern and classic vehicles. We are a full service auto shop from classics to modern vehicles. Feel free to contact me with questions. I will give a 10% discount to any board member.

10-11-2005, 07:11 PM	#7
76bonanza Senior Member Join Date: Mar 2003 Location: St robert Mo Posts: 2,001	ok so best set up is tranny and brakes off intake and pcv off carb. the fitting that screws into the intake were can you find those? I never see them for sale anywere looking for some different ones. Thanks __________________ 1968 c10 lowered 3" 4" 355/Th400 built by Hatfield racing in joplin MO

10-11-2005, 06:39 AM	#5
bejay Registered User Join Date: Aug 2005 Location: missouri Posts: 136	the pcv is a controlled vacum leak, if you put it on the rear manifold fitting it will lean out number 8 cylinder to the point it will not even hit at low idle speeds that is why it should be hooked to the carb. hooking your brake booster to the rear manifold fitting would be your best option and would provide more vacum to the booster than the way its installed now teed in with pcv valve.

10-11-2005, 08:50 AM	#6
truckdude239 Senior Member Join Date: Sep 2005 Location: Lewisville, Nc Posts: 10,228	wow i glad i looked at this because my pvc is hooked to the manifold lol was like that when i got the truck



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