Are you running one to one carb linkage or factory progressive type? If progressive, the medium risers and low risers employed the balance hose. ( I don’t know about high risers).
Some aftermarket vac pods do not have nipples. I don’t run a connecting hose on my set up. ( no nipples, pods have opening rate adjustment screws).
I confirm both secondaries open. I run one to one linkage.

I run 1 to 1 linkage. Took it out this evening and had a contact switch mounted at each carb secondary link. Hit it in a 2nd gear roll and both indicator lights lit up at same time. They were set to make contact at about half open. Loved it and it pulled hard lighting up the drag radials!

Why not add a stroker crank assembly to the block you have...like 445. Power and torque where you can use on the street in a light Cobra....scary FUN !

I have to come here to try and get good info on the characteristics of the tunnel wedge intake design. I have my custom made intake of same design but made to fit
the 9.5 deck Windsor engines of 351 thru 440 cube stroker versions...mine being 427.

Now what I have going on is the intake is very cold natured on startup even on an 85 degree day.  With the idle and cruise A/F at 13.4 to 14 at normal 180 F temp it runs fine with great response running off front carb in a progressive linkage setup on a pair of Holley 770 CFM carbs with vac. secondary.

On first startup I have to keep RPM in the 1800- 2000 range to keep it running at a 14.9 range...higher RPM the richer it is. Anything below 1500 and it sputters at 16 A/F ratio. As it comes up to temp it will settle down at it's 1000 rpm idle at a 13.4 A/F. Drive  it and then after a 20 minute shutdown with engine still warm  you still have to keep the RPM up to 1500 for a decent fast idle and then it will settle down to it's normal running. No chokes on the carbs. I tried a manual Holley made  choke and it did do the job but the pivoting cable lock and flex from even a solid cable did not let the choke blade fully open...too much slop.

Now on a cold startup I plug in my engine coolant heater which I used on my other intake during chilly temps to heat the intake and that helps. Other than this it pulls like crazy above 4000 RPM!
Note....carb jetting is now 76 Primary and 84 in Secondary both carbs.  Stock .075 IAB and stock R-3310 idle fuel jet. Idle screws  1 turn out all around.

Do you guys that run the FE 427 Tunnel Wedge intake on the street have same issues or is mine a strange case? Thanks for any help!

Well I was impressed with the results and that's all that matters! Was my idea to have it made.

One of the guys did a dyno compare on his hot street 418W. Victor Jr. with 830 Holley vs. the Tunnel Wedge with a pair of Holley 465 carbs.  The Tunnel Wedge was bolted on
right out the box with no port matching or other work. 1 inch 4 hole spacers on the intake and heads were AFR 205 I believe.  Took some jetting changes to try and get the cylinder A/F as close as possible as O2 sensors for each header pipe. The Tunnel Wedge was ahead by 30 HP and 11 Torque at 6400 RPM !

Back in the 70's we would slide a new cam in and add a can of the GM Break-in oil additive and NEVER had a problem. Installed many cams back then of different makes and with my brother's 426 Hemi we installed the Racer Brown STX-22  Super/Stock cam and lifters using the race springs of that time....solid flat tappet and no issues at all ! Back then no mention for a light break-in springs and it all worked fine.  Must be that everyone wants crazy ramp velocity which requires much stiffer springs for that extra power?

Before making changes to the intake, you need to know how much the heads flow, and how much the manifold runners flow.  If the manifold flows 110% or more of the head flow, then it is unnecessary to modify the intake for street usage.  Making the radius larger will only slow down the velocity in the runner because it shortens the runner's effective taper.  Joe-JDC

Thanks for the info on the top radius Joe!  After I posted this question I found some info that making it larger will slow the air speed in runner a bit. This intake is cast for the 351W 9.5 deck engines and I will run it on my tried and true 427W which has about same bore/ stroke as a 428. Heads are TFS 225 HP and flow 330/258 at .600 lift. Cam is a 241/249 .600 HR and has been running great for 15 years now. Valve springs by Pac replaced 6 years ago.

Would it help flow into runner if this radius area is larger than  the 1/4 inch radius as cast?  Will be running a 1 inch 4 hole merge type spacer also.