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Discussion Starter #1
I have a 69 cat with a 351W 4bbl carb. I had alot of work done to the car recently, including getting the carburetor tuned. I have the cast aluminum walking cat valve covers and had a hard time finding the right size grommet that fits the larger size hole.

Well I got one today but I had to cap off the line to the carb because the vented cap had a smaller diameter tube and would not work. Now heres my problem, I started the car and got it warmed up real good. I noticed that the engine seemed to start lugging after awhile and the car would have went off if I hadn't got in and gave it some gas. I noticed that it was idling at around 600 to 700 rpm's. But it sounded more robust and throaty at about 1k rpm's, (the sound I remember when I first bought it).

My questions, what is the correct rpm for this engine, is 1k too much? Do I need to vent the crankcase fumes back to the carburetor and finally am I doing damage to the engine by capping off the line to the carburetor?

Thanks all, Martin.
 

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AT or manual trans? 700 or 900 I think.

The breather you have - was it a push in style? Many of those for whatever reason have an oriface the size of Texas on them! I know what you mean. I think they are designed more for race car type evac tubes than street wise sensible connections. The better ones are billet machined, but way more expensive - but give you more options on outlet size. Try to get one that is baffled internally too. I had trouble with many of them allowing oil to sucked in under high RPM's. I ended up using a PCV valve that reduced the diameter of the breather side to the correct size for the carb base. Then I covered it with stainless braid to match the rest of the hoses and it looked pretty decent. Mr Gasket makes a good selection of push in style gromets. The one that worked for me had a baffle design built into it where it passes through the valve cover. It helped to orient the opening away from the oil splashing around off the rockers/roof too.
 

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Discussion Starter #3
My car is a 3 speed automatic and yes the breather is the push in type. I saw some of the grommets with the built in baffles but none were big enough. Tomorrow I'll stop by a speed shop and see if they can help me out. I think I'll also adjust the idle to 900 rpm's like you suggested, the mechanic said 700 was right but I was used to the smooth throaty sound that the engine always made. I'm still trying to get rid of some of the clutter in my engine bay and I hate a dirty engine and this issue was making it an oily one.

Yesterday I left 2 16 foot tire trails at the entry/exit to my subdivision, now I can see the cats marks every time I leave or come home. Isn't life grand? Thanks for the help and suggestions, Martin.
 
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