250 Inline 6 - Offenhouser Intake Questions - The 1947 - Present Chevrolet & GMC Truck Message Board Network

jaxncurtis · 02-15-2021, 03:54 PM

Hoping someone can help me out with my new setup on my Inline 6 250 engine. Im adding the Offenhouser Intake and I cannot figure out what do with the two holes on the back of the intake?

I know it is not for Water as the Heat Plate is on the bottom which I have that covered. Just not sure what to do with these two holes pictured.

**litebulblsc** · 02-15-2021, 04:05 PM

Vacuum ports?

**DeadheadNM** · 02-15-2021, 04:57 PM

Bump to engine and drivetrain

Dead Parrot · 02-15-2021, 05:40 PM

2nd the vacuum port thought. If you don't need them, plug them.

vince1 · 02-17-2021, 03:45 AM

Brake booster, PCV?

**mattfranklin** · 02-17-2021, 08:07 PM

Or they may me to make it compatible with a later model that needed a temperature sensor or temperature activated vacuum switch for emissions.

And like the other guys have said... If you don't need them, plug.

BTW, it's really good looking manifold.

02-15-2021, 03:54 PM	#1
jaxncurtis Registered User Join Date: May 2017 Location: Gilbert, AZ Posts: 33	250 Inline 6 - Offenhouser Intake Questions Hoping someone can help me out with my new setup on my Inline 6 250 engine. Im adding the Offenhouser Intake and I cannot figure out what do with the two holes on the back of the intake? I know it is not for Water as the Heat Plate is on the bottom which I have that covered. Just not sure what to do with these two holes pictured. Attached Images

02-15-2021, 04:05 PM	#2
litebulblsc Senior Member Join Date: Aug 2006 Location: LaSalle Mi Posts: 498	Re: 250 Inline 6 - Offenhouser Intake Questions Vacuum ports?

02-15-2021, 04:57 PM	#3
DeadheadNM Carpe manana Join Date: Dec 2010 Location: Eau Claire, WI Posts: 12,278	Re: 250 Inline 6 - Offenhouser Intake Questions Bump to engine and drivetrain __________________ 1972 K5 CST Highlander Blazer: http://67-72chevytrucks.com/vboard/s...d.php?t=708547 1972 K20 Cheyenne Super: http://67-72chevytrucks.com/vboard/s...d.php?t=528308 Members met: ORANGBLAZ, 2003 silverado, MikeCofield, BB72CHEVKT, Duncan&Son, Sameyrasmea72, THENEWMEXICAN, HotRod C/10, brianthelion02, Sport/Truck, ryanroo, michael bustamante, Dirt's72, Already Gone, WestButteTruck, 57taskforce, Moreyel, painterljp, AASmedic, SoCoC10, Lumaestas, carbuff382, Chevyland

02-15-2021, 05:40 PM	#4
Dead Parrot Registered User Join Date: Aug 2012 Location: Oklahoma City, OK Posts: 2,472	Re: 250 Inline 6 - Offenhouser Intake Questions 2nd the vacuum port thought. If you don't need them, plug them.

02-17-2021, 03:45 AM	#5
vince1 Registered User Join Date: Jan 2013 Location: Calgary Alberta Posts: 1,164	Re: 250 Inline 6 - Offenhouser Intake Questions Brake booster, PCV?

02-17-2021, 08:07 PM	#6
mattfranklin Senior Member Join Date: Dec 2011 Location: Moraga, CA Posts: 799	Re: 250 Inline 6 - Offenhouser Intake Questions Or they may me to make it compatible with a later model that needed a temperature sensor or temperature activated vacuum switch for emissions. And like the other guys have said... If you don't need them, plug. BTW, it's really good looking manifold. __________________ (Very) Slow-Going Build Thread: Stock 1970 Short Step with Stock 1970 LT-1 http://67-72chevytrucks.com/vboard/s...d.php?t=567340



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