MGB 1977 MGB Intake

[kyreb1862]

I seem to remember reading once that you could cut out the intake section of a RB one piece manifold. If I did that, would the intake section still be usable with an exhaust header? I still have some ideas for the single carb set up but I want to be able to lose the cat and go with a less restrictive exhaust manifold.

 

[AlanT]

Sounds like you want an Austin Marina set-up. It uses a single sidedraft (CD175 of HIF6) and a dual downpipe ala MGB.

Alan T

 

[ccougill]

I've seen it done but I can't remember if it was necessary to fab a cover or not. Tony will chime in soon I hope

 

[kyreb1862]

Sounds like you want an Austin Marina set-up. It uses a single sidedraft (CD175 of HIF6) and a dual downpipe ala MGB.

Alan T

Where could I come up with such a set up?

 

[rick_ingram]

Actually, you can put an HIF6 on the existing MGB combo manifold. I ran one on my 1978 MGB for several years.;

Granted, exhaust flow was still forced to do some crazy escape patterns....but it was somewhat better performing than the ZS175...and made for a GREAT conversation piece.

 

[tony barnhill]

Yep, whack the intake off the exhaust & toss the exhaust...use the intake with either the ZS carb or one of the larger carbs (HS-6, I think)...use an early MGB exhaust or a Peco header....

 

[Bret]

Hmm? Ya know I was thinking about doing this too. The emissions legal EFI kit from Moss bypasses the EGR valve and that's the only reason to use the stock intake/exhaust manifold.

Not that emissions is a concern for John, but I could use a short header and attach a aftermarket catalytic converter. I believe Magnflow or someone like that makes what's called a "pre-cat" (for two stage or duel cat systems) that would work better than the original and less restrictive.

Shouldn't affect tail pipe emissions part of the test. But I wonder if it'd get flagged by the inspectors when they performed the under the bonnet inspection.

Might not be an issue. Especially given the fact that half the time the test tech's at the state run "Smog Test Only" stations can't even locate the cat on their own.

 

[kyreb1862]

Now I just got to get me a look at an Austin Marina intake manifold. I need to determine the mounting flange thickness on either the Austin Marina intake or the cut off MGB intake so I can determine what brand header I can use. Luckily emissions inspections are not something I have to deal with.