Hot Rod Forum : Hotrodders Bulletin Board

Hot Rod Forum : Hotrodders Bulletin Board (
-   Hotrodding Basics (
-   -   A few ideas on manifold vacuum advance? (

chevy302builder18 10-19-2012 10:51 PM

A few ideas on manifold vacuum advance?
I havent came acrossed a intake vacuum fitting that allowed three vacuum lines to run off. what do you guys suggest for small block chevy stock manifold? also id like to add, my three way fitting broke, and i had to plug it off. im also thinking about installing a BIG vacuum ball in place of the older plastic vacuum canister

Greg T 10-20-2012 07:27 AM

Back of the carb, front of the carb, plastic T fittings...the possibilities are endless.


RWENUTS 10-20-2012 08:19 AM

Go to the junkyard and look on Ford intakes for multi-trees. Put one on your chevy. Instant HP. LOL!!

chevy302builder18 10-21-2012 02:35 PM


Originally Posted by RWENUTS (Post 1601115)
Go to the junkyard and look on Ford intakes for multi-trees. Put one on your chevy. Instant HP. LOL!!

Its not for horse power its for daily driver for now. vacuum problem that has my head spinning. Id just like to think there is a big difference between port vacuum and manifold vacuum in a sence that there is a "duration time" between both, not about how many inchs one can pull in vacuum. what im saying is one is closer to your intake runner on the head, and one isnt. just like longer runners in dual planes vs single plane open plenums.

Greg T 10-21-2012 09:20 PM

The only difference between ported vac and manifold vac is that ported is a signal pulled from above the throttle plates and manifold vac comes from below the throttle plates. Ported is (or should be) 0 at idle and increase with tip-in, whereas full manifold vac is highest at idle and deceleration.

cdminter59 10-22-2012 04:27 AM

Afew ideas on manifold vacuum advance
Here is a website with the fiitings you are looking for. Expensive fittings. 68-78 Corvette Intake Manifold Vacuum Fittings | Corvette Parts and Accessories Here is another site. East Coast Chevelle | Chevelle Restoration Car Parts

chevy302builder18 10-22-2012 11:39 PM

corvette fittings look like the ones im looking at. not bad for something that is exactly a direct replacement. I do have the plastic tees, and one way vacuum fittings to fit vacuum hoses together. i have deleted the charcoal canister for now since the main source of the leaks come from that. sacrifices for throttle response.. turn the dizzy shaft easier and more freely. but relative to the fact it has the same structural design as the old day dizzy coil in cap. i cleaned the sludge off the EFI dizzy coil in cap, took vacuum advance parts off the worn out one and made a clean break for a more up to date distributor so i know my distrubutor bearings arent worn. also looked at the distrubutors springs, the distrubor was the original with stretched out wieght springs. so i ended up breaking my vacuum manifold tee in the process of resurecting this engine with new distrubutor and vacuum checking. The Main concern was that the fitting also sent a vacuum to the transmission and this leak had made the engine back fire. so i just thought naturally it was the distrubutor. but when i un hooked the vacuum line going to the manifold from the tranny, it just broke while thinking it was the worn dizzy, or blown head gasket. I was furious but also happy my idea wasnt the head gasket being blown cause it didnt like idling. But this didnt make me not change out the distrubutors

All times are GMT -6. The time now is 04:42 PM.

Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0 PL2
vBulletin Security provided by vBSecurity v2.2.2 (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.
Copyright 1999 - 2012. All Rights Reserved.