Modified stock intake
 

So I took a shot of modifying my stock iron intake. Tried to copy Cliffs intake pics. Traced out what I wanted and the took a Sawzall to the big pieces. Then took a electric die grinder and blended in the rest. Right side was easy but the left was much thicker and took some time. Using the same 1/2" spacer which has a notch already so I didn't remove any metal from the center divider. Just opened it from a 4 hole spacer to matching the intake.If it doesn't gain any HP at least its lighter now. Lol

Looks real good. Hmmm, i could use that Spacer.

Looks good. That's pretty much how I've done them with the notch in a short spacer etc...

With one small exception. I kept the front bores a little smaller to closely match the throttle bores of the Q-jet as per how Jim Hand did it. I think the theory was a little more velocity and better throttle response, but I haven't noticed much difference either way.

Smaller on the spacer?? The bores on the intake primaries are pretty much stock from about 12 to 3 oclock on the right and 12 to 9 on the left. And the secondary holes are stock in the back part. Pretty just went from the factory holes and blended the sides. If you look at the left primary you can tell the grinder never even touched that at all around 12 oclock position. Hopefully didnt lose much on the throttle response.

On the primaries I leave the thickness in the center divider with blending, pretty much like Jim Hand did it, and taper it in larger as it enters the plenum. The divider quickly tapers in to a skinny center divider between the secondaries. I do the same with a spacer. Shoot me an email and I'll send some pictures if you want to see it.

Not that it's a big deal. I've done them the way you have it too and don't notice any difference, it'll run perfectly fine like that.

What gasket are u using between this spacer and the carb

I use a thicker one between carb and spacer...like a 1/8th" or so. Then a thinner one between spacer and intake. I cut both of those to the shape of the spacer.

I need to go look and see what I have

Both gaskets started life as 4 holers, Used scissors and utility knife to make them look like thee intake opening.

Got your email Scott, I'll send you some pics tonight as soon as I figure out this computer.

Here's how I did mine. Looks like I should have spent more time in the plenum radiusing the corners.

The outside of it resembles a RA/HO at first glance. Sure is a lot lighter and runs cooler.

Dang, i have pent-up Cast Iron Intake performance anxieties. My 4234 which matches my R 96 A heads is Stock, and needs the Mahoney treatment. I am willing to settle for the above.

Looking at post 11. I wonder about leaving the top of the secondary, front to rear divider intact, and grinding a opening below it to connect the sides. Wondering if leaving some of that top F-R divider in place and contouring it for port velocity............have not seen one like that.....I have seen all of Jim Hands doings, for intake plenum mods...

That's what Jim Hand was doing on the front portion which I've done on a few as well.. I'm trying to get pics to Scott. Basically the width of that center divider in the front is left in place basically matching the throttle bores of the Q-jet, and then contoured into the plenum. One side needs a lot of grinding to contour it properly, the other side not so much. The idea was to keep port velocity up on the small primaries. I do the same thing with the spacers.

Mine ended up like this when I was putzing around with intakes…..note the 1” spacer

It couldn’t match the RPM on my combos…..had fun carving it up though!

Here's an SD Perf CNC modified intake to compare to.

Dennis

That's the one I was trying to copy. I did find online a pic of the jim hand modification that formula Jones was talking about. Only way to get that shape now would be to get another spacer and shape it to that which now would only be making a 1/2 " ledge.

The SD intake is a copy of Cliff's iron intake. Cliff had posted several times, pictures of his original modified intake.

So I'll throw this out -the factory must have had a reason for 4 holes especially going all the way down the deep plenum-and Chevy had several 3 hole factory intakes. Why?

I sent pictures to Scott how I've done a few of them, which is the old Jim Hand way. I've also done them like the Cliff Ruggle way which Dave as SD has copied for Cliff.

I think what has happened over the years is the Jim Hand way morphed into the Cliff Ruggle way and now the Cliff version is the widely accepted (more recent) way of doing it.

Either one works about identical from what I've been able to tell from my own personal use.