Air cleaner to valve cover vent
 

So ... my valve cover vent pipe doesn't line up with the fitting on the air cleaner.

Couple of questions ... the vent pipe is from a 2 bbl air cleaner setup .... different than the four barrel? It seems a bit too tall.

Also ... how thick is the OEM carb gasket? The one I'm using is probably 3/16" thick .... I think it was supposed to be "just like the original" but you know how that goes. Was thinking if it's to thin and the fact that I'm using no carb to air cleaner gasket that it could lower the air cleaner enough to cause the problem ... but that would be a stretch ... about a 1/2" or more height different between the cleaner and the vent tube right now.

its gotta be those 5" tall gold MORROSO aluminum covers your using ???!!!! ....

come on now !

Im fairly sure 2 bbl and 4 bbl use the same vent tube in 68 69 swapped several out thru the years...

pictures always help my scatter brain ....

I'll post up a picture later today. Engine is a stock 68 400, carb is a 71 (704) Q-jet, air cleaner is "supposed" to be a 68 .... I drilled it for the 704 carb vent ... in such a way it leaves some room for adjusting the rotation of the cleaner base. Vent tube came from a ( I think) 73 2 bbl engine.

Wondering if ... heads shaved about .005, block decked about .005, carb gasket too thin, no air cleaner gasket ... might all add up to enough lower on the air cleaner base to make the tube not fit.

Only pic I can find on my phone at the moment that shows the tube.

I zero decked my block & shaved the heads just enough to make them flat. That dropped everything enough where I had to have my manifold cut for the ports & bolts to line up squarely again.
No problems at all with anything fitting afterwords.

It's just that now I have a Pontiac "small block" :D :D

http://forums.maxperformanceinc.com/...1&d=1591305246

Here are some photos ...

Is it possible 68 GTO valve covers are taller than a 1973 350?

Is a 704 Q-jet shorter than a 702

Is the OEM gasket a big honking thick thing?

http://forums.maxperformanceinc.com/...8&d=1591309556

http://forums.maxperformanceinc.com/...9&d=1591309560

http://forums.maxperformanceinc.com/...0&d=1591309565

Does your tube have a collar on it where is meets the valve cover grommet? Mine does not & can slide up and down quite a bit.

At least I think thats the case, I'll need to go look, but I am pretty sure it does not

Mine has the collar .... hmmm ... could that be the difference between a 73 pipe and a 68?

Went through my photos ... best one I have of what I have labeled "Absolutely Correct" untouched cars .... I see no collar on the tube.

Dang it. I mislead you. Mine does indeed have the collar! Sorry about that.

Does this help? 4-1/4" from the valve cover to the center of the tube.


https://forums.maxperformanceinc.com...1&d=1591312135

How tall is your air cleaner assembly?
it looks a fuzz shorter than mine based on the pictures I see. Maybe its just the angle.

Heres some photos of mine about 40 years ago.

https://forums.maxperformanceinc.com...9&d=1591319031

https://forums.maxperformanceinc.com...8&d=1591318999

https://forums.maxperformanceinc.com...7&d=1591318966

Dataway, I think you should be ok, have you tried attaching it to the air cleaner with the short rubber hose? Mine does not line up exactly but the combination of the rubber grommet in the valve cover and the short 1.5” rubber hose at the air cleaner allow for some play and adjustment.

In the attached pics you can see mine does not line up great, but is fine once attached. Also attached pic of my tube with reference rulers. Mine does have a raised collar as a stop at valve cover grommet. These are all original parts.

My air cleaner seems to be at roughly same height as Ragtop’s. Maybe slightly (1/4”) higher as the center of tube to top valve cover is 4.5”

I should mention that I have a pretty thin carb to manifold gasket. Was always going to ask what gasket style was originally used, & I kept forgetting about it. ;) you can see it in the pic above. I don't recall were I even got that one.

That’s probably the difference between ours....my gasket between intake and carb is 1/4” thick. I don’t know what is correct or proper gasket thickness. Can’t remember source or why I used 1/4” thick one.

I was wrong about the my reference photo ... upon huge magnification, yes it has the collar. I'll measure mine tonight and see where I stand.

Curious ... did a Firebird come with a different air cleaner base? I bought the air cleaner used, it was presented as a 68 part, now that I think about it, didn't specify if it was A body or F body origin.

Don't think it's a 68. The vacuum actuator on the snorkel doesn't have any lettering on a 68 air cleaner unless the valve was replaced. 69 and up have the Auto ThermAC lettering.

That is an absolutely stunning engine compartment 68ragtop!

RagTop ... mine is 3 7/8 to the center line of the cleaner base fitting, Yours appears to be 4 1/4.
So mine is close to 1/2 lower.

The top of my air cleaner to the same place you measured on the valve cover is 5 5/8"

OG68, I did change the actuator, came off a 73 air cleaner. Although, the one that was originally on it had lettering so a good chance it was a 69 or later, but not 704 carb style with the hole for the carb vent.

I'd be interested in a picture of the inside of the air cleaner base.

Crankcase vent pipe should be the same (other than a notched end inside the valve cover) for both years in reference and has like a 95 degree upward slope.

On a base I purchased for my '69 Firebird years ago, I had laid the air cleaner flat on the edge of a table and measured from the carb. ring to the table and it was like a 1/4" difference between that and my '70 GTO measurement. I think I used a veneer caliper and measuring from the top of the folded over ring to the table was like 0.95" (supposed '69) vs 0.70" ('70 GTO).

Will take some more pics today. One with a tape measure.

My pipe does not have the notched lower end by the way.

My total height appears to be the same 5 5/8 as 68Ragtop ... but the fitting appears to be lower.

KK68 ... and your total height looks about 1" higher than mine !

All my 69’s have the formes collar to hold the pipe at the valve cover grommet. Looked up the pipes inmy November 69 MPC...

All 68 V8 9790992
All 69-70 V8 except RA 9790992

I’m curious what changed in 69, air cleaners and valve covers all interchange between 68 and 69.