98 GT Upgrade...Help me decide

[JRod]

I've had my 98 GT for over 5 years now. Bought it with the intention to build it up but ended up just using it as a beater. I've decided its time to start the build. Currently it has 138000 miles on it and is running great. I am going to have to replace the T45 transmission since it is showing its age. It currently has 2.73 gears which will be changed out to 3.73 or 4.10's possibly.

I've looked into doing either a PI swap with new cams like this (if you have a better suggestion on a head swap please let me know too) or find a 98 cobra motor with low miles and do a swap. My budget is around $6000 figured I would buy a used or new T56 or possible convert to an auto which leaves me around $3-4000 for the motor.


What I'm concerned about is will my stock bottom end handle the head swap or would I be better off finding a cobra motor. Or possibly buying a new 2v block and do the head swap on it.

Just for grins hear is a pic of my mustang and F150

I am leaning towards the PI swap since I would like to change the wheels and tires with the budget money too, but that can be done later if the motor is too old to handle the upgrade. I only plan to take it to the track occasionally, no hard use. And later on maybe put on some FI, but that is a big maybe since that is another $4-6000. Any help is appreciated.
Thanks, JRod

[91CoupeMike]

Mach 1 swap or... 03 cobra swap.

If you go Mach swap build the bottom end, it needs better rods if you want over 450rwhp.

Ideally the Mach block weighs less, and if you want around 600-700rwhp go with cobra rods and pistons and throw a kenne bell on it.

Cheapest 600rwhp out there.

And the swap is easy.

[redrocket5.0]

[jnobles06]

this is the cheapest way to make the most power. I wouldn't do a t56 swap I'd go with a promotion built t45 it's cheaper and they are stronger than a stock t56. the final drive is almost the same as a t56 anyways. then I'd pick up a set of used patriot heads of the forums, a set of pistons, rods, cams, and a 150 shot.

t45 built with a clutch $2k
new rods pistons rings gaskets ect $1500 (use stock crank)
used patriot heads $1k
used cams $400
used nitrous kit $400
machine work ect ~$600

[JRod]

Mach 1 swap or... 03 cobra swap.

If you go Mach swap build the bottom end, it needs better rods if you want over 450rwhp.

Ideally the Mach block weighs less, and if you want around 600-700rwhp go with cobra rods and pistons and throw a kenne bell on it.

Cheapest 600rwhp out there.

And the swap is easy.

Thanks for the input guys.

As for swapping in a mach motor, to make sure I'm right I've heard that swapping in a mach motor all I need is the motor and accessory drive. My wiring harness and ecu will work with no modification other than my IAC sensor and fuel rail brackets. If I was to use the mach cop would I have to modify the harness or ecu or would it be easier to just stay with my coil packs?

Also can I take off the shaker scoop and fab up some piping for the air inlet or is the shaker scoop all part of the intake manifold? Not wanting a shaker scoop on my 98, doesnt look right imho.

[91CoupeMike]

Thanks for the input guys.

As for swapping in a mach motor, to make sure I'm right I've heard that swapping in a mach motor all I need is the motor and accessory drive. My wiring harness and ecu will work with no modification other than my IAC sensor and fuel rail brackets. If I was to use the mach cop would I have to modify the harness or ecu or would it be easier to just stay with my coil packs?

Also can I take off the shaker scoop and fab up some piping for the air inlet or is the shaker scoop all part of the intake manifold? Not wanting a shaker scoop on my 98, doesnt look right imho.

The shaker scoop is part of the hood, and not the intake manifold.

It would be easier to stay with the coil packs like you have now, you'll just need to find early 4v valve covers that used wires.

It should just drop right end, and you'll need a tune afterwards.

This will be the best option, over a Pi swap or anything the 2v has to offer.

With stock Mach 1 engine internals you are limited to 450-470rwhp before you start to bend and break connecting rods. The block is good for around 700hp and is the lightest of them.

You could do an 99-01 cobra swap and have teskid block, which is strong enough to do whAtever you want.

Teskid came in 96-98 cobras, 93-98 Mark viiis, 99-01 cobras.

03-04 cobra blocks are cast iron, the Mach 1 and aviator blocks are aluminum.

There are c heads and b heads. And a lot of differant cams.

B heads respond well to boost, but you can't put as big of a roots style on them like you can the c head.

Just do some research and itll make sense.

[jnobles06]

The shaker scoop is part of the hood, and not the intake manifold.

It would be easier to stay with the coil packs like you have now, you'll just need to find early 4v valve covers that used wires.

It should just drop right end, and you'll need a tune afterwards.

This will be the best option, over a Pi swap or anything the 2v has to offer.

With stock Mach 1 engine internals you are limited to 450-470rwhp before you start to bend and break connecting rods. The block is good for around 700hp and is the lightest of them.

You could do an 99-01 cobra swap and have teskid block, which is strong enough to do whAtever you want.

Teskid came in 96-98 cobras, 93-98 Mark viiis, 99-01 cobras.

03-04 cobra blocks are cast iron, the Mach 1 and aviator blocks are aluminum.

There are c heads and b heads. And a lot of differant cams.

B heads respond well to boost, but you can't put as big of a roots style on them like you can the c head.

Just do some research and itll make sense.

I'm pretty sure he has to switch to a Mach/ cobra computer and maybe even his fuel since he has the return style still. and then he'd out of budget on a stock 270whp Mach motor only good till 450hp when he could of had an 300WHP n/a 2v that able to handle 600 at the wheels, and who really needs more than 600hp at the wheels on a street driven car anyways? anything over that is just a waste IMO.

[BlackGT]

Coyote for something different and more power than a PI 2 valve...

[jnobles06]

Coyote for something different and more power than a PI 2 valve...

yeah because that is a straight forward budget conscious swap.

[matts5.0]

Lq4 4l80e

[Magnimike1]

The shaker scoop is part of the hood, and not the intake manifold.

It would be easier to stay with the coil packs like you have now, you'll just need to find early 4v valve covers that used wires.

It should just drop right end, and you'll need a tune afterwards.

This will be the best option, over a Pi swap or anything the 2v has to offer.

With stock Mach 1 engine internals you are limited to 450-470rwhp before you start to bend and break connecting rods. The block is good for around 700hp and is the lightest of them.

You could do an 99-01 cobra swap and have teskid block, which is strong enough to do whAtever you want.

Teskid came in 96-98 cobras, 93-98 Mark viiis, 99-01 cobras.

03-04 cobra blocks are cast iron, the Mach 1 and aviator blocks are aluminum.

There are c heads and b heads. And a lot of differant cams.

B heads respond well to boost, but you can't put as big of a roots style on them like you can the c head.

Just do some research and itll make sense.

Mike, all shakers on most cars, as with the 03-04 Mach, are on the engine and not the hood.

[matts5.0]

Mike, all shakers on most cars, as with the 03-04 Mach, are on the engine and not the hood.

He means it is not structurally part of the intake.

[KungFuHamster]

OP let me ask this: what are your goals for the car.

[91CoupeMike]

Mike, all shakers on most cars, as with the 03-04 Mach, are on the engine and not the hood.

It just mounts to the top and feeds the intake tube, it can be removed.

I like to see Mach 1s with roots style chargers and the shaker on top!

[Magnimike1]

It just mounts to the top and feeds the intake tube, it can be removed.

I like to see Mach 1s with roots style chargers and the shaker on top!

I am quite familiar with the design. It blows up with the intake from Nitrous backfires though.