Engine How to solve Mustang GT40 plenum cleareance problems when using tall valve covers

JTRSMC

Member
Oct 13, 2022
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Madison AL
Hello mustang tech comunity.
I need some technical assistance in finding the right tall valve cover that gives me clearance over my scorpion roller rockers but is not too tall that causes too much interference with the plenum.
I know they GT40 plenum spacers but I have a engine brace and I do not want to go too high with the spacer. I see 1" and .5" available.
There is one more thing I need to stay within 100 budget on the valve covers.
I am seeing customer fabricated aluminum valve covers. Does anyone know if these would work in my application?
Pictures attached
 

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There have been 3/8" spacers available for the GT40 lower, which would be a good option if it fits with your strut tower brace. If your are in an "off road application", removing the large 2" EGR spacer and going with a 3/8",1/2". or 1.0" EGR Delete spacer will move the throttle linkage toward the plenum and add more valve cover clearance. The MC Machine throttle bracket is very helpful for linkage clearance and adjustability too.
 
I run these


I had to remove the baffle and grind down a few casting bosses to clear my Crane Gold rockers.


I run a 3/8" spacer to clear them. Nothing else needed. I ran the Explorer upper plenum first, before switched to the 93 cobra plenum. Both had same clearance. Fits with my STB, stock hood and A/C and everything else, as you can see. Hood blanket clears, and I’m running energy suspension poly engine mounts. K-member is in factory location (not lowered)

Here’s a 3/8” spacer

1670423651451.png
 
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Just to add.

I clear these rockers with those covers 149CA1BA-DF87-4473-B205-77F5AF51D7E6.jpeg

Clearance is tight but it does make it with a 3/8” spacer. This was with the explorer upper.
482E17FD-19C9-4293-BE26-F9D4846BE478.jpeg E55BE322-BB90-4C08-8090-C526698DBCE7.jpeg

Here’s back when I had the explorer upper before I changed my mind and went Cobra

402CB660-E998-4907-AF13-31984B45AB28.jpeg
 
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There have been 3/8" spacers available for the GT40 lower, which would be a good option if it fits with your strut tower brace. If your are in an "off road application", removing the large 2" EGR spacer and going with a 3/8",1/2". or 1.0" EGR Delete spacer will move the throttle linkage toward the plenum and add more valve cover clearance. The MC Machine throttle bracket is very helpful for linkage clearance and adjustability too.
Thank you I have found the same 3/8 phenolic spacers on ebay. I am not in a offroad application so I cannot remove egr spacer not only that but i have the vacuum ports hitting on the other side. I do believe the 1" spacer will clear the valve covers. I will be checking on that soon. I am not sure about the MC Machine throttle bracket.
 
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Wow I really like your valve covers and engine arrangement. So you had to modify them to fit. I would probably have to do the same with my scorpion rockers.
I want to try one more option. I came accross these on ebay recently. They are custom fabricated valve cover that are only 3-3/8" high and they are guaranteed to fit over my scorpion rockers without modification.
Here is the link:
kcid=16&mkevt=1&mkrid=711-127632-2357-0&ssspo=I7IN4M5aT7u&sssrc=2349624&ssuid=pzD0SapnTHq&var=&widget_ver=artemis&media=MORE
The seller mentioned that using the valve covers with a 5.0L EFI a spacer may be needed.

So I am thinking a 3/8" to 1/2" spacer may work.
If not I will go with what you. Sounds like everything will fit the same as your set up.
 
I have the same Ford Racing valve covers as M5L5. I'm using Scorpion low profile 1.6RRs and a Cobra intake. I didn't need to clearance the valve covers or remove the baffles to clear the RRs. I also do NOT run a plenum spacer. All I did to get the intake to clear was slot the throttle bracket screw hole a little so I could slide it up to clear the valve covers.
 
Oh wow ok. Well I didn't know they even made low profile 1.6RRs. I think I stuck using a 3/8" or 1/2" spacer. I did receive the new custom fabricated valve covers and they fir great. Here are some pictures.
 

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The ones in the pic? They just look like button head allen bolts with a washer.

I used ARP 12-point bolts on mine.

I believe they are 1/4-20 thread but do not know the appropriate lenght off the top of my head.

If you wanted studs, you can just get 1/4-20 studs and then nice nuts.

I get all my hardware off mcmaster-carr.
 
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A local option if you have a Home Depot or Lowe’s:

1/4-20 x 1-1/2” stainless socket set screw


1/4-20 stainless hex nut


1/4 stainless flat washer


You get the idea. Can grab it all locally and it works very well on both my cars.
 
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A local option if you have a Home Depot or Lowe’s:

1/4-20 x 1-1/2” stainless socket set screw


1/4-20 stainless hex nut


1/4 stainless flat washer


You get the idea. Can grab it all locally and it works very well on both my cars.
thank you!