Author Topic: 79 t/a with olds 403 pcv valve questions  (Read 308 times)

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Offline Rapp17

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79 t/a with olds 403 pcv valve questions
« on: June 09, 2017, 09:25:02 PM »
Hello, sorry for being really new at this but I bought a 79 trans am to restore with my grandfather. We've gotten it running good so far and have done some upgrades to it but since I bought it it's always been smoking through the passanger side breather. It's got after market valve covers that the original owner put on it and has two breathers without a PCV valve. I was curious if someone could tell me how a pcv system hooks into the carb and what would be best for my valve covers since they're aftermarket. The carburator is also after market and is a Holley 1850-5. Also I do think it has some excessive blow by since it is a pretty high mileage engine and it's getting oil in the breathers so would a PCV valve cause it to burn up oil?
« Last Edit: June 09, 2017, 09:26:57 PM by Rapp17 »

Offline Rapp17

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Re: 79 t/a with olds 403 pcv valve questions
« Reply #1 on: June 10, 2017, 07:28:44 PM »
Here's a picture of my current setup if that helps any.

Offline NOT A TA

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Re: 79 t/a with olds 403 pcv valve questions
« Reply #2 on: June 11, 2017, 12:03:07 PM »
The 1850 should have  two 3/8" vacuum fittings in the baseplate. The one in the rear can be used for your brake power booster and the one in the front for your PCV.

IIRC the 403 had a tube for filtered air to enter the engine from the air cleaner assembly to the drivers side valve cover and a PCV valve in the pass side valve cover with a tube going to the carb base at the front.Air needs to flow through the engine, google "positive crankcase ventilation".

With only breathers and no PCV valve you will get hazy air coming out the breathers that makes a mess. Air should only go IN the engine from a breather and be pulled through the engine and to the carb through the PCV valve. Crankcase air should not come out of a breather.

Post a pic of each valve cover with breathers removed so we can see if you can install a PCV valve on one of them easily.
John Paige


Dear Not A TA,
This is Tin Indian's wife. Would you please stop posting pictures of your car? Especially ones with er, ummm, sidepipes. I'm dizzy already and have to get up early in the morning.  :-X

Offline Aus78Formula

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Re: 79 t/a with olds 403 pcv valve questions
« Reply #3 on: June 11, 2017, 01:31:30 PM »
Looks like the regular chrome Edelbrock covers painted blue. You need the grommet to suit that takes the PCV.

Offline Rapp17

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Re: 79 t/a with olds 403 pcv valve questions
« Reply #4 on: June 11, 2017, 10:55:24 PM »
I got to looking at it and sorta got the vacuum lines figured out. For whatever reason the pcv / brakebooster port on the carb is being used for the vacuum advance with a homemade adapter. The brake booster is routed to a port on the manifold. Here is a picture of that and of the valve covers with the breathers off. Sorry for how messy the engine bay is, we just replaced an intake manifold gasket that was leaking antifreeze at the front. I'm also in the process of putting in the original fan shroud and a new radiator since the old one was was not properly installed and really small.