So why do 3.9's suck

[DumpsterFire]

3.9 Magnum isn't a bad running engine until the seats crack which isn't as common as V8 heads. or the plenum gasket poops out.
Typical Magnum stuff.

Hell I ain't seen a magnum head with out cracks between the seats

 

[MOPARMAGA]

Hell I ain't seen a magnum head with out cracks between the seats

I've seen 1 lol

 

[DumpsterFire]

I've seen 1 lol

We're you working on the line in Detroit?

 

[MOPARMAGA]

We're you working on the line in Detroit?

No, lol.
Recently a guy brought in a set for a valve job and to be surfaced & alas the 1st magnum head without a crack.
I should have taken a picture with it .

 

[MOPARMAGA]

The Mopar 3.6 is a winner power and economy wise at give or take 300HP.
We've rented several minivans and all had great power and returned an average of 27 MPG.

I work on them all the time, tuliped valves is there plague

 

[Dave_J]

Everything is a compromise. If the donor for the light build included a perfectly fine 3.9 and plenty of hood clearance or no hood, I'd use it but leave room in front for the smoother running v8. I'd don't like the height (for hood clearance) or vibes that come with any big v6, L4, or L5, to try to address with balance shafts. A 3.9 magnum would be a beast in a miata.

Or in a 1984 Dodge Rampage.

 

[Dave_J]

If I was going to do a v6 it would be a 3.5 from late 90s and or the later 3.5 early 2000s.
98 intrepid with a 3.5 would make a 5.0 gt mustang owner reconsider their hotrod stop light to stoplight.
I have no idea how one would make it rear wheel drive

A 3.5L 215ci V6 in the back seat. The engine is in front of the trans so it would be a MID ENGINE.

We put a Turbo 2.2 in to a Brazilian Puma GTa to replace the VW 1600. Went from a slow heavy tail dragger to a wickedly fast screamer. The 2.2 was ahead of the trans so it too was Mid Engine.

 

[Dave_J]

I have a complete 3.8L Regal Type T Turbo that had a Q-Jet on top. It would make a 3.9 a power house. The Q-Jet sits on a manifold that feeds into the Turbo and has a 3 bolt flange that bolted to the 3.8's intake manifold. The Turbo center section is the same as a 1979 Mustang 2.3 Turbo, no water cooled bearings so OIL selection was paramount.

 

[MOPARMAGA]

A 3.5L 215ci V6 in the back seat. The engine is in front of the trans so it would be a MID ENGINE.

We put a Turbo 2.2 in to a Brazilian Puma GTa to replace the VW 1600. Went from a slow heavy tail dragger to a wickedly fast screamer. The 2.2 was ahead of the trans so it too was Mid Engine.

View attachment 1716360555

Awesome