Hacked my intake. How much is too much?

[512 cad]

OK, so when I was putting together my cad motor(2200-5400 RPM powerband) a few years back I wanted to keep a stock looking intake(plus I was broke!) and everything I read said to hack out the plenum dividers.  I never could find anything more detailed than that.  So I hacked it all out to the same shape as an open center carb gasket.  I took everything out level with the bottom of the runners, smoothed off all the corners as much as I dared and as far in as I could reach.  Then I gasket matched it to my iron heads and blocked off the exhaust crossover.  I have half a dozen of these intakes, so I wasn't too scared to hack a lot out.  This was my first try at intake/head porting, so I wonder if I should have left part of it in?  Also I have a one inch, 4-hole spacer on it.  I haven't touched the spacer yet but thought I should taper and smooth it some.  Any thoughts?     

[omaha]

It is ok for the secondaries to "share" their space in the plenum but for best fuel mileage and response, the primary side should have some kind of divider. You could epoxy a divider back in to the manifold. I would use steel 1/8 plate and some good epoxy like Devcon steel epoxy OR Marine-tex epoxy. Have the divider come back all the way to the top EXCEPT in the area of the secondaries. This area should have a notch of about 1 to 1 1/2 inches down so the two sides can share at WOT. Make the notch about ~2
(maybe more) inches long just in the vacinity of the secondary butterflies. This is info that I have read about on this forum and in Jim Hand's book about Pontiac performance. I guess he did all his research either on the drag strip or on a dyno so I know it is valid.  (Jim's been around for a looong time). Good advice for anyone running a 2 plane intake on a big engine.  The actual dimansions of the notch may vary but you get what Im saying here.  BTW, marine tex epoxy is gasoline resistant.

[512 cad]

Thats what I was afraid of after reading some of the other posts here.  I have several intakes around so I will probably just hack another one and do some back to back testing when work slows down a bit.  Guess I need to research this Jim Hand guy, as pontiac stuff is pretty foreign to me.
Thanks! 

[omaha]

yes. the Jim Hand book is just "GOLDEN" when it comes to tuning and HP advice. The drag strip tuning advice is great. Most of the info can be relavant to all makes of engines except of course for the Pontiac specific stuff. By the way, he made his divider. Also, he made his own carb spacer (out of white pine no less!!) I guess you have to experiment with the size of the notch on the secondary. If you screw up, just fill it back in.

[Cliff Ruggles]

Best advice I can provide is to leave the divider in place.  Remove as much as you want in each plenum and between the primary and secondaries.

At most, put a small "divit" between the secondaries, or use a gasket that's open there.

We have observed HUGE power losses on the dyno (torque production) when the divider was cut down.

In actually use, the engine will often "stumble/hesitate/bog" going quickly to full throttle at low rpms as well.....Cliff

[512 cad]

Thanks!  You know, when I finished that intake I thought it looked too good to hide under a carb.  Guess I'll hang it on the wall in the shop.  When folks ask "What's that for?"  I'll take a swig of beer and belch.  then I'll just say "Sculptural Art".
512 cad
 

[512 cad]

Post Script:
Mabey some fancy art gallery will give me $50 for a messed up intake off of a $20 dollar car!