Trick Flow Series R to Box R Upper Intake Road Block

Habu135 · Mar 31, 2026

I'm in the process of swapping out a Trick Flow R Series upper intake (bottom photo) with a Trick Flow Box R upper intake (top photo). During installation I quickly realized that my Accufab adjustable fuel pressure regulator (FPR) is hitting the back passenger's side of the new Box R intake. It appears I need to relocate my FPR which will also trigger a requirement for new fuel rails. I'd appreciate anyone sharing with me what parts are needed for this swap as well as any other suggestions you have. Thanks

TOOLOW91 · Apr 1, 2026

Habu135 said:
I'm in the process of swapping out a Trick Flow R Series upper intake (bottom photo) with a Trick Flow Box R upper intake (top photo). During installation I quickly realized that my Accufab adjustable fuel pressure regulator (FPR) is hitting the back passenger's side of the new Box R intake. It appears I need to relocate my FPR which will also trigger a requirement for new fuel rails. I'd appreciate anyone sharing with me what parts are needed for this swap as well as any other suggestions you have. Thanks

Being you have an r already , I think you’re going to pick up hp with the upper only in the way higher rpm range and I’m not sure the juice is worth the squeeze

rednotch · Apr 1, 2026

Some have used a stock style adjustable with stock rails and a little clearance work. Standard sells a stock style adjustable for around $40 on rock auto lmr bands it on there site as 5.0resto and up charges it... Slow 5oh on corral used to have pics up but looks like they died with photobucket. https://www.corral.net/threads/ford...n-aod.1739866/?post_id=13632522#post-13632522

Habu135 · Apr 1, 2026

TOOLOW91 said:
Being you have an r already , I think you’re going to pick up hp with the upper only in the way higher rpm range and I’m not sure the juice is worth the squeeze

I already bought the Box R. This intake should finalize (no, really) the mechanical modifications to the engine.

Habu135 · Apr 1, 2026

rednotch said:
Some have used a stock style adjustable with stock rails and a little clearance work. Standard sells a stock style adjustable for around $40 on rock auto lmr bands it on there site as 5.0resto and up charges it... Slow 5oh on corral used to have pics up but looks like they died with photobucket. https://www.corral.net/threads/ford...n-aod.1739866/?post_id=13632522#post-13632522

I already have an adjustable FPR, it's just that it doesn't clear the new Box R style intake. This isn't really an uncommon mod. I'm wondering what others have done specifically to resolve this clearance issue.

rednotch · Apr 1, 2026

Read the link.. the stock style regulator are smaller than after market...

Habu135 · Apr 1, 2026

rednotch said:
Read the link.. the stock style regulator are smaller than after market...

I see in post #29 the author states that he bought a Ford adjustable FPR due to the tightness. It's a PR557 on Rock Auto and LMR. Doesn't appear to have a vacuum line.

rednotch · Apr 1, 2026

The top slotted section is the vaccum line connection its just a stock style adjustable unit vs the much larger ones like kirban bbk areomotive etc.. But with a little clearance work it will fit a box upper and stock rails...

Habu135 · Apr 1, 2026

rednotch said:
The top slotted section is the vaccum line connection its just a stock style adjustable unit vs the much larger ones like kirban bbk areomotive etc.. But with a little clearance work it will fit a box upper and stock rails...

Well. that's exactly what I need. What "little clearance work" is needed?

TOOLOW91 · Apr 1, 2026

Habu135 said:
I see in post #29 the author states that he bought a Ford adjustable FPR due to the tightness. It's a PR557 on Rock Auto and LMR. Doesn't appear to have a vacuum line.

I would go this route if it’ll work rather than the whole rail setup .

Habu135 · Apr 1, 2026

TOOLOW91 said:
I would go this route if it’ll work rather than the whole rail setup .

TOOLOW91,

I'll be following your install, specifically how you ran your vacuum lines to the vacuum tree. I'm curious though where you purchased a replacement vacuum line from your fuel pressure regulator. I'll likely need a longer length of tubing.

TOOLOW91 · Apr 1, 2026

Habu135 said:
TOOLOW91,

I'll be following your install, specifically how you ran your vacuum lines to the vacuum tree. I'm curious though where you purchased a replacement vacuum line from your fuel pressure regulator. I'll likely need a longer length of tubing.

I have regular rubber vaccum hose from the parts store. Runs from the back fitting around my intake to my strut tower to my regulator. Just ts off to the blow off valve as well.

Habu135 · Apr 1, 2026

TOOLOW91 said:
I have regular rubber vaccum hose from the parts store. Runs from the back fitting around my intake to my strut tower to my regulator. Just ts off to the blow off valve as well.

And it appears the two other vacuum lines from the driver's side intake run to the vacuum tree and what some other attachment there on the firewall? What is that for that middle line?

TOOLOW91 · Apr 1, 2026

Habu135 said:
And it appears the two other vacuum lines from the driver's side intake run to the vacuum tree and what some other attachment there on the firewall? What is that for that middle line?

Big one feeds the tree to send vaccum to everything - HVAC / Boost gauge/ meth controller

Dedicated line to map sensor for the Holley ( I have had Holley efi on this car since 2017 or 18)

Other one goes to the regulator / Blow off valve

Habu135 · Apr 1, 2026

This one goes to a blow off valve? It looks like it connects from the firewall above that green square to the rear port on the Box R.

TOOLOW91 · Apr 1, 2026

Habu135 said:
This one goes to a blow off valve? It looks like it connects from the firewall above that green square to the rear port on the Box R.

That’s the dedicated line to the map sensor

Habu135 · Apr 1, 2026

I don't see how this is going to work with the oem style adjustable fuel pressure regulator. The height comparison is almost the same and the Accufab is rubbing as is with an approximate 3/8" gap before the upper and lower mate up. I can't raise the upper intake via a spacer because it won't fit under the hood and I can't see any way to make either fuel pressure regulator work because they're simply too tall.

Habu135 · Apr 1, 2026

rednotch said:
The top slotted section is the vaccum line connection its just a stock style adjustable unit vs the much larger ones like kirban bbk areomotive etc.. But with a little clearance work it will fit a box upper and stock rails...

What clearance work will permit this oem style fuel pressure regulator to fit under the Box R?

Take a look at post #17. I'm out of ideas how this could work without a huge spacer between the upper and lower intakes which would then require a cowl induction hood.

TOOLOW91 · Apr 1, 2026

You can either grind into that upper some - or tweak that fuel line regulator pad down some with a BFH

TOOLOW91 · Apr 2, 2026

This guy did what I said - they said they cut the plate I guess for a relief and then bent the plate down and it fit

Trick Flow Series R to Box R Upper Intake Road Block

Habu135

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Habu135

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