I am just wondering if any one is cutting the clover leaf out of the top of a 4500 Indy intake. At this point I cannot afford to send it out to be professionally done but i am more than willing to do it myself if there is an improvement.

Any real world experience would be good,

451 cubic inch b engine that will be run on the throttle stop in super street.

Thank you

Yes. Remove it. Makes a big difference at 512 cubes on a Low deck! Removed it myself and re-blended everything.

I also see that you cut back the dividers. Looks really good!

I can't leave anything alone.

Which version of the Indy 400-3, early or late?
Individual injector bosses or two per boss?

Mine has the two bosses on each pad.

Removed mine as well. I used an angle grinder to cut the meaty parts back and then blended the rest with my foredom porting tool.

I have no back to back tests or anything, but everyone I've talked to that makes power w/ them said to get rid of it...so I did just that on my Indy 426-4 hemi manifold and the 440-3 on my wedge. The old 426-3 manifold I used to have that was ported by Indy for Mike Daurity's KOS car also had the cloverleaf removed.

I have no hard data either, but Wilsons suggested i remove the cloverleaf and put a 4 hole tapered spacer on top so i did. With a couple other improvements i did pick up 3.5 tenths and 3.5mph next time out.

Anyone have data on how much this mod only helps? It can be dyno numbers. or ET.

I ran mine back to back, before and after porting....It was worth .07 in the 1/8th on my 512 low deck. I think its especially important on the low deck intake. I think that intake has less plenum than the RB intake.

My 470 picked up a significant amount of power after Wilson ported the Indy intake. As cast, the Indy intake was very rough and the port sizes were inconsistent. I also did not like the way the plenum looked but I'm not a porting expert so I didn't touch it. Wilson removed most of the cloverleaf and then lengthened two of the dividers by welding on extensions.

I've own both styles,, the later one with a common boss doesn't have the dividers protruding into the plenum as much as the earlier ones is what I remember.
I haven't done any work on the dividers on any of the 400-3 or 440-3 intakes I've used, I did notice the differences though
I'm sure Indy didn't make those changes for no reasons, especially after seeing what Wilson did to Andy late style Indy 400-3 intake

Mine had them on it, as its only 2 years old....I removed them and the Indy logo. Again, I couldn't help myself.

Mine appears to be the same intake as Andys minus the Wilson Touch!!!!!!!

I have had it for years so I am assuming it is the old style. Am I correct?

No, his is a new style with the single oval EFI boss connecting across on both runners, the early ones had two raised individual bosses, one on each runner

Thanks Cab. I guess mine is the new one then.

I really appreciate the comments. I am thinking there is going to be some aluminum filings in my future.

Years ago, I saw an intake flange matching the throats above it on its upper surface, but it had only the bottom of the flange flared/radiused out (using the largest curve for the thickness of material) but each corner was radiused away from itself - toward the other corners.
Why?
Did it work?

Well its offical! I am pot committed now. Put cut off wheel to aluminum amd the clover leafs are gone. Going to be an interesting project!

Completely cutting ALL runner dividers IS NOT the way to correctly modify this manifold. However, some lengths could use adjustment. This is a manifold that worked really well AND it fixed the distribution issues inherent. I was only 'allowed' an evening to work on this so, it isn't 'done' ...I'd have cut away some of the clover at the flange among a few additional asthetic improvements. ( another 2-3 hours work?)