Didn't realize I still had a BT on the shelf to answer your questions.  Here are a couple of pictures.  On the BT, the pad is not at the same angle as the Mummert DP or SP, and the front of the intake is nearly 1/2" different from the rear. Joe-JDC

JDC

Thanks, I will allow for about 2’’ more height and measure my current clearance.

The carb pad is ~1¾” higher on the Mummert single plane intake when compared to the Mummert dual plane intake.  The carb pads heights are close to being the same on both the Mummert and Blue Thunder aluminum dual plane 4V intakes.

Lorena, Texas (South of Waco)

How much taller is the Mummert single carb intake than than Blue Thunder?

The intakes are single plane for 4150 style Holley, and single plane with Dominator carb pad.  The intake manifold on the right( in the picture above) is a single plane 4150 that I ported after I got back from the 2019 EMC for testing on the 303Y where it made about 12 extra horsepower.  I wanted to test it on my 375 Y, and I have been waiting on the opportunity.  There is a big difference in horsepower on a well built engine over the dual plane intakes.  There was a 13 hp difference in the 4150 style carbs, and 30 hp difference on the 4150 single plane with the Dominator and super sucker on the 375Y.  With the single plane Dominator and tunnel ram, there was a 35 hp difference on the 375 Y.  

JDC

Very tasty intakes.
what are the differences on the three intakes shown together and how can I get one.
John if your viewing this please send me a PM or email rcphillips20@gmail.com prices and availability 

Check the posts below this where the answers are listed.  Single 4V makes 613 hp.   Joe-JDC

Here's the link.  
SINGLE 4V INTAKE MAKES 613 HORSEPOWER ! (y-blocksforever.com)  


JDC

Very interesting stuff!... So, do we get the answer to JDC's question, as to which combination gave the most H.P & or Torque readings?..  Or is this possibly going to be released in Y-Block Magazine first ?.. 


Paul

Thanks for the in-depth answer. Very thorough.

       A  L  A  N   F  R  A  K  E  S   ~  Tulsa, OK    

These heads are angle milled .125", and when received from JM, the exhaust side was not milled back to the same angle as a stock head causing the header to hit the oil filter and block.  I added the 1/2" spacer to move the header out further, and also give the exhaust port some taper to speed up the exhaust flow into the header.  Ted milled the exhaust side of the head back to the correct angle for me before this rebuild, and I chose to keep the plate there to help the exhaust port.  It was allowed in the Vintage Class at EMC, so I chose to make use of every "trick" to up the horsepower, if possible.  Moving the header away from the sparkplug wires is also a good thing.  Joe-JDC

JDC