i cant seem to find anything about this!

[Tempted]

Map can be ran off of any vacuum port on the TB. Not having a PCV also allows a build up of pressure and can cause rear main leaks and blowouts.

 

[MOBS]

Yeah, in theory only the diesels have the engine vacuum system to decrease oil seepage thru the gaskets....I never actually thought about the pcv doing that since it keeps a constant flow of air thru the engine. The pcv also only works at idle, loses vacuum when throttle opens.

 

[copernicusd]

so i could just put as t in and run the map off the front
what about sensor on side?
do i just get a plug off a 94 and cut mine and wire in the new one i guess

 

[Tempted]

Yes, you can just use a T and run the MAP off the front. Get a vac gauge and ensure you are pulling proper vac, otherwise the MAP isn't gonna let it run right anyway.

 

[MOBS]

I wonder if the vac from front port is the same as from rear? I've never actually checked that, always plugged **** off

 

[DRAGGIN95]

Map can be ran off of any vacuum port on the TB. Not having a PCV also allows a build up of pressure and can cause rear main leaks and blowouts.

Word, I have seen this happen, especialy in Nissan's and Volvo's with a steel thread in PCV valve, the chevy type that push in the valve cover will usually pop out of the valve cover with enough pressure but the thread in type won't so something is going to give somewhere!

 

[MOBS]

Actually the pcv on our tbi engines is an exit for the air already, tbi pulls air through it while rear connection allows filtered air to enter the crankcase. You can unhook the pcv and air will come out but not go back in, the rear port is 2-way, so it'll let any air in that's needed. I pulled both and threw valve filters on

 

[Tempted]

Word, I have seen this happen, especialy in Nissan's and Volvo's with a steel thread in PCV valve, the chevy type that push in the valve cover will usually pop out of the valve cover with enough pressure but the thread in type won't so something is going to give somewhere!

Subarus are bad about it too. Have a rear main blow, replace it only to have another blow due to a PCV failure. Happened in an 86 GL Wagon 4x4 I had.

 

[Tempted]

I wonder if the vac from front port is the same as from rear? I've never actually checked that, always plugged **** off

The vacuum is the same no matter where the port is. It isn't going to be any higher at one area than another.

 

[Massey]

OK I just skimmed this thread and I did not hear any one mention about the intake bolting up different. The Vortec heads only use 4 bolts per side where the TBI engines use 6. This means you are not going to get proper sealing in the middle of the intake, without using a designed for Vortech heads manifold. I dont know how big of an issue this is going to be with the engine but I imagine it could cause issues. The EGR for a vortec manifold is pulled from the front exhaust ports were the TBI manifold uses the center cross over port. The Vortec heads do not have a center cross over and the bolts that hold the manifold down are also verticle, not angled like the TBI manifold is.

Not all SBCs are the same there have been many changes over the years and not all parts are interchangeable. The Vortec blocks do not have a provision for a fuel pump nor do they have the lobe on the cam for the fuel pump. The fuel pump area is cast into the block still but the bossings are not machined.

Massey