3.4 SHO V8 into a 1998 Mercury Grand Marquis

Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.

justinmo87

New Member
Joined
Feb 3, 2024
Messages
2
Reaction score
0
Location
Indiana
Hi all. I have aquired my grandparents old 98 Mercury Grand Marquis. I wanted to hot rod it a little bit and take the 4.6 out and put the Ford/Yamaha 3.4 V8 in it and turbo or supercharge it. My biggest issue is trying to find a transmission for a RWD setup. Any ideas about what transmission would work or if the one it already has would work?
 

SHOrod

Torrie Tuned
Joined
Jan 1, 2006
Messages
1,059
Reaction score
408
Location
Cedar Rapids, IA
While I can appreciate the uniqueness, why would you go to the effort of trying to retrofit a smaller, less reliable engine with less of an aftermarket following versus doing a turbo or supercharger on the existing 4.6L? Is the engine in the car bad? Of course even if it is, replacing that engine with a used 4.6 or 5.0L would likely still be less expensive and require far fewer modifications than swapping in a 3.4L.

Unless you're really in love with the idea of putting a 3.4L in, I suspect your best chances of actually completing the project would be to stick with an engine that's already been known to work in the car. If it's because you want something that looks pretty when the hood is open, a Coyote engine sure would look nice. Although I'm not sure if the Coyote uses the same bolt pattern as the older 5.0L or not. If it does though, the up-front cost of the engine is probably still less than the cost of all the fabrication work to make the 3.4L work.

By all means if this is a passion project and something you really want to do, go for it and don't let me discourage you. But if it was just something you were considering to be different or because you already have the 3.4L engine, you may want to give it a bit more thought.

-Rod
 

E1

Crash Tested
Joined
Jan 24, 2003
Messages
686
Reaction score
397
Location
Chicago area
Bang for the Buck?
I've got an '03 Cobra SVT Eaton supercharger, elbow, throttle body and 39# Cobra injectors. Now, the older 4.6's require an adapter plate, but I'm sure it can be done. I might be coaxed into letting this setup go to an SHO person, these things are not cheap, but you could be up and running way below what the SHO swap budget would be.

I have supercharged a few V8 SHO's in my career and 10.5:1 compression is a heck of a place to BEGIN boosting from. Me and Carter can SHO you more than a few melted pistons....

Also, there is NO replacement for displacement. Anything one can do to a small motor can be done on a larger one as well. The 3.4 is my favorite engine but it sorely lacks torque at lower RPM's. Dragging that full sized car around would be a chore.

Cool factor? Absolutely. Transmission out of a Ford Ranger 2.5 Duratec is said to be best starting point for bellhousing pattern. Haven't tried it myself.
 

justinmo87

New Member
Joined
Feb 3, 2024
Messages
2
Reaction score
0
Location
Indiana
Bang for the Buck?
I've got an '03 Cobra SVT Eaton supercharger, elbow, throttle body and 39# Cobra injectors. Now, the older 4.6's require an adapter plate, but I'm sure it can be done. I might be coaxed into letting this setup go to an SHO person, these things are not cheap, but you could be up and running way below what the SHO swap budget would be.

I have supercharged a few V8 SHO's in my career and 10.5:1 compression is a heck of a place to BEGIN boosting from. Me and Carter can SHO you more than a few melted pistons....

Also, there is NO replacement for displacement. Anything one can do to a small motor can be done on a larger one as well. The 3.4 is my favorite engine but it sorely lacks torque at lower RPM's. Dragging that full sized car around would be a chore.

Cool factor? Absolutely. Transmission out of a Ford Ranger 2.5 Duratec is said to be best starting point for bellhousing pattern. Haven't tried it myself.
I just think it would be cool to have a Japanese engine in a Ford. Plus, I like the tubular look the Yamaha SHO engines have on top of the motor. I believe the only thing I need to do is with the sprockets and cam shafts is weld them together, which shouldn't be too hard to do.
 

E1

Crash Tested
Joined
Jan 24, 2003
Messages
686
Reaction score
397
Location
Chicago area
I know it's cool. I know it's pretty. Apples to apples your are GIVING UP 40+ pounds of torque. It is exponentially WORSE at low RPMS due to lesser displacement. It is going to be a DOG out of the hole. You may get it to run, but you won't be setting land speed records.

Go here - https://v8sho.com/SHO/SHO R.T.S..htm

You will want the positive displacement supercharger low end torque curves. Forget about turbos and centrifugal superchargers, they don't offer maximum low end grunt.

I have welded HUNDREDS of V8 SHO motors (x - 4 cams per motor). It is not for everybody, but I would have to guess if you are considering a project like this, that project is well withing your ability to do or have done.

Your big challenges will be adapting and controlling a transmission - What computer scheme will you use?
Mounting the engine will require imaginative engineering, not impossible, probably fun.
Computer and matched wiring harness for the Engine Management. DO you incorporate it to the transmission or run parallel systems?
Exhaust headers will be hand built, one-offs.
Front suspension will require substantial modification. Car will sit like it has no motor at all with that aluminum 360 pound engine in place of the Iron 4.6.

I've been there/done that just about anything one can imaging on a V8 SHO and any part of one - and I'm a relative baby on this forum compared to many of our members.

If you want to do this just to do this, then that is the best reason of all. Go for it. Keep my contact info, I got lots of parts that can be cut up to make the unique parts you will need to make, but I'm sure it can be done if your heart is in it.
 

luigisho

SHO Member
Joined
Nov 2, 2001
Messages
12,762
Reaction score
4,712
Location
va beach,va
I agree with displacement to vehicle size/wt. It is what I don't like with current manufacturers' engine downsizing- even with turbo charging to make up the displacement loss.
 

gamefanatic

SHO Member
Joined
Feb 20, 2005
Messages
699
Reaction score
246
Location
Barstow, CA
IMHO the "reliability" of the 3.4 SHO engine is pretty good once the CAMs are welded. Having said that, the 4.6L will have more room for power and better suited for the heavier vehicle. But I only have my own experience of my 2 SHO's to go against.

I'm prety sure you could mate the 4.6 tranny to the SHO with an appropriate adapter. I've seen a 3.2L SHO adapted to a BMW tranny many years ago.
 

Forum statistics

Threads
105,620
Messages
1,165,376
Members
14,954
Latest member
ddizzy81

Members online

Back
Top