Ford V8 Discussion Discussion relating to getting the most out of your Ford-based V8 Miata's engine

GT40 Intake question

Old 01-09-2018, 05:40 PM
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Default GT40 Intake question

If I have vacuum for the brake booster and fuel pressure regulator, can I just block off the other vacuum lines? I am not going to run an EGR or any emissions stuff.
Picture A is where I get my brake booster and FPR vacuum, and the drivers side picture has one of the lines I need to cut and plug.
Attached Thumbnails GT40 Intake question-picture-.jpg   GT40 Intake question-drivers-side-vacuum.jpg  
Old 01-10-2018, 05:25 AM
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I had to plug a few on mine, so you should be good.
Old 01-10-2018, 08:15 AM
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That set-up will never fit under a stock hood of a Miata. My advice would be to ditch the fancy valve covers and upper intake spacer unless you are planning to run a huge hood scoop, and I know about huge hood scoops.
Old 01-10-2018, 08:28 AM
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I have a feeling that you are going to have to get creative when trying to attach the heater hoses at the firewall because of those valve covers.
Old 01-10-2018, 08:37 AM
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To answer your question, yes, you can cap off the unused vacuum ports. As far as the one that you have circled (and the other one supplying the PCV) I would cut those off/ remove them and install threaded plugs and pick up my PCV vacuum elsewhere.
Old 01-10-2018, 12:55 PM
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I have Ford Racing covers and explorer intake. I had my lower machined down per Martins suggestion and also have my subframe shimmed down 1/8. I had to use EGR spacers to move my TB out to clear the valve covers. Still have not tried closing hood, that is coming up on the to do list. I had to plug the ports on the intake as well.
Old 01-10-2018, 01:13 PM
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Originally Posted by tbone heller
That set-up will never fit under a stock hood of a Miata. My advice would be to ditch the fancy valve covers and upper intake spacer unless you are planning to run a huge hood scoop, and I know about huge hood scoops.
I'm not worried about the hood, you can check my build thread the car is not a sleeper. The valve covers were necessary to clear the rocker arms on the AFR heads.
Old 01-11-2018, 08:09 AM
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Originally Posted by othersalem
The valve covers were necessary to clear the rocker arms on the AFR heads.
Ford Racing roller rockers will fit under a stock valve cover from a 1987-1993 Mustang.
Old 01-14-2018, 09:06 PM
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Hi,

TBone is correct. This wont fit and I have just been through it myself to know

Yes you can simply remove those fittings and plug up the intake with a screw in bung for the front port and a good silicone sealer for the rear fitting.

There are other rocker covers that you can use (as suggested by TBone) but there is also a great cast alloy type from trickflow for the ford 5.0l, which are lower profile than the ford racing set you have now (which look to be the tall version) AND they clear a studded rocker setup. I am using these now in my build.
No spacer is required between the upper and lower intakes to get this to work.

You will still likely have clearance challenges but the removal of the spacer gets you 3/8-1/2 in closer to where you need to be.

Also TPS switch may be the biggest headache from a clearance perspective. Well it was for me








The heater hose and Air cone line clearance
Old 01-15-2018, 05:47 AM
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To add, I have the shorter finned FR valve covers, not the tall ones in your pics.
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