With the little bit of research I've done, it looks to me like the blocks are
the same.
The 5.2 and the 3.9 have the same tranny bolt pattern.
The front of the motor is also the same for the timing chain/gears, cover and
most of the brackets are interchangeable on the V6 and the V8.
Both have a 3.91 bore and 3.31 stroke. (I'm not 100% sure on the stroke.)
Recently another DML Member sent me an e-mail that said "They use the same
main bearing journal caps and on the 90 5.2 the same throttle body " I have
not been able to verify this.
The motor mounts are in four parts. A left and right bracket and left and
right insulator. The right bracket part # 4412102 bolts to the block and the
front of the tranny housing. The left part # 4348555 just bolts to the block.
The book I have lists those two part numbers under both the V6 and V8
applications. The insulators (which are different V6 to V8) are either bolted
or welded to the frame (I'm not sure which) They are also bolted to the front
axle housing to hold it in place. Because of the axle housing and the right
bracket, I would think the mounts are in the same location.
Does anyone know if Chrysler relocated the mounts when making a Dakota V8
block or has it's location changed over the years. I too am planning on a 360
for mine. Will an early 70's small block have the mounts in the same
location? I have also looked at the Magnum 300hp crate motor as well as the
Magnum 380hp crate. Because my truck still has to maintain a certain level of
street use, I think the 380hp is overkill. I would probably go with the 300
but $3200 plus a carburetor and another transmission (don't like the idea of
300hp flowing through an A-500) makes my rather buy an older block and build a
motor.
Walter_Felix@MSN.COM
http://www.geocities.com/MotorCity/Downs/9219
-----Original Message-----
From: owner-dakota-truck@buffnet4.buffnet.net On Behalf Of JT McBride
Sent: Thursday, November 13, 1997 12:55 PM
To: dakota-truck@buffnet.net
Subject: Re: DML: Motor mounts
I won't swear to it, but I think the block is the same. The bolt-on
motor mounts are the weird item there. As I understand it, the Dakota
frame was designed for the V6, and the V6 designed for the Dakota. The
3.9l V6 has the last two cylinders lopped off, so the motor mount
castings line up with the frame. With the longer block of the V8, the
brackets mate the block casting with the same frame location.
You have bigger problems than you anticipate.
When Shelby squeezed a V8 into the Dakota, he had to strip the accessories
drive to a minimum, and use electric fans. Still a tight squeeze. When
the factory offered the TBI V8 in '91, they designed a new nose, which
the Magnum Dakotas got too, that gives you 3 or 4 more inches up front.
I understand the sheet metal will bolt up to earlier fenders... You're
still looking at new hood, grill, bumpers etc.
The 300 hp 360 Magnum crate motor runs $3200, and has the dual-plane
manifold that will fit under the hood. I don't think you'd be complaining
about "underpowered" after a Magnum injection!
Good luck,
Jim
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