Progress Thread 1998 Gt Navi Swap, With A Tremec Tr3650


Active User
Jan 22, 2018
I started this build with the idea from a co-worker. When my 4.6 2v blew, I knew I was gonna go more displacement with a 5.4 .
So my co-worker says to me one afternoon why not a 5.4 dohc?
After researching it just a bit I found that the 5.4 2v isn't much of an upgrade over stock, also there's so many out there already. So with the notion of being different but still bad ass and budget minded as I work for a living as Technician who supports a family with limited Mustang $ per say.
With a lot of convincing and sweet talking the wife she agreed for me to build up my car however I wanted with a 5k limit.
So I personally found a donor at a bone yard got it home, tore it down to find timing chain guides were wiped out as well as the first crank journals and bearings.
With that a full build was in order, it's .040 over, balanced bottom end, heads shaved .020 , 3 angle precision valve job, ported and polished by yours truly.
Stock cams were ok and reused. Lifters,valve springs, all new motorcraft.
I'm expecting to make over 400 to the flywheel no problem provided a custom tune.

What I had to buy in addition to make this swap work with mostly junkyard good used parts.

Exhaust manifolds are 98 cobra
Lower intake is 2001 Navigator
Upper intake is 2017 Singletary Customs
Flywheel is 2001 Cobra
Fuel rail is from a 2001 expedition
18" fuel line extensions Singletary Customs

Parts I could still use.........
Gt off road x pipe. I cut the lh side approximately 1 ft from the o2 sensor and was able to wiggle it up to the 5.4 but not without it nearly touching the body just above k member. So I heated and beated until a finger fit behind it.
Stock k member reused with 1/2" spacers a literally made by stacking washers and purchasing longer bolts from Ace Hardware.
I used all Navigator accessory drive except the power steering pump for that I just swapped the pulley to the GT pump with the hopes of one day adding a blower of some sorts I wanted the 8 ribbed belt and my 4.6 would chirp the belt in between shifts......not should chirp not belts...........

The intake I thought would be my biggest hurdle after viewing what they cost to clear a decent looking hood. I just couldn't bring myself to spend that kinda cash when I was confident I could build my own for a fraction of the cost. I kinda used the MMR design aspect in combo with the Navigator lower half. I used 3/16 steel for a base plate and for the throttle body adapter plate, the top and sides are if 18 gauge steel. It took about 16 hrs to build and prep for install. When I was done I have literally $90 in the entire thing plus my time.

Outside of that I've got the obvious cold air kit, 47lb injectors,03 cobra MAF on the way. Last piece of my puzzle before dyno day next month in Daytona!
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