early 4.6l B-series head question???


Aug 2, 2006
I have a 93' Lincoln mark VIII 4.6L with the B-series heads. My question is this, do you need to run the intake manifold runner control, used to separate the primary and secondary runners. can you eliminate it or will it affect performance in any way. reason being intakes for this motor i have found to insanely priced. and am going to give making my own a shot. and for calculation reasons need to know if i need the imrc plates.

any info would be greatly appreciated

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Aug 2, 2006
i have also made stainless steel plates for the valve covers to convert it to coil on plug and ideas on what would be the best coil to run


Founding Member
Dec 11, 2001
Olathe KS
I would say yes, you need to keep the plate. The idea of the different runners is to better tune the intake for a wider operating range. This allows the engine to operate on one runner during low speed operation for better low rpm torque and around town manners, and still allows another runner to open up and feed the engine more air the upper rpm range. Often, the runners are a different diameter or length to tune for a certain operating band. Shorter and fatter primaries favor the high revs, while skinnier and longer primaries favor the lower rpm range.

Looks like the B heads have two intake ports for each cylinder cast into the head itself. Sure, you could build a manifold to eliminate the plates and dual runners, but this would likely hurt the low and mid range torque quite a bit.


Aug 2, 2006
yeah that's what i was wondering. to give an idea the car is going to be turbo-ed. know i don't how much that changes the factor due to the turbo forcing the air and the engine not being n/a. i had also in my searches found that ford racing makes a delete plate. it is the same width so on and so forth just says removes the shaft and blades. cause i am trying to gain all the info to compile into one basic design for the intake.

thanks for all the help
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