I have been receiving some interesting info on M-1 manifolds drilled out for EFI
application, using crate motors in new trucks with EFI and head modification. I can
verify some of this, but do not have actual proof as to problems experienced. This is
what I was told by MOPAR Performance:
They have the M-1 manifold, but it is not yet available drilled out and do not have a
part number for the MP1. This part is ONLY for race applications and requires
modifications to your existing systems if used. For example, you must remove one ear
of the air condition compressor bracket. You no longer have EGR and must weld the
tube closed to the exhaust manifold. Also, you have to keep the EGR vacuum hoses
blocked off but remained attached to avoid fault codes. Cosmetically, it is a mess.
You are hard pressed to find a place for all the sensors. The thermostat is a bitch
to relocate and requires a odd ball modification. The 4 barrel throttle body is not
yet available and I have head it requires a spacer to avoid hitting on the fuel rail.
If the two barrel is used you have to manufacture an adapter, or buy one from
Chrysler. In any event none of this is available from Chrysler as yet. I can attest
to all above, but do not know where my modified M-1 manifold came from, except who I
bought it from. (I had to remove it)
I stand corrected on my statement that crate motors are not magnum engines. They are.
However, you can only use the 300 HP version with the Chrysler EFI. The cam is too
radical on the 380 HP version and the engine will run erratically. I can attest to
that. Further, if you use a cam that is more radical than OE, it may not be
compatible with the Chrysler EFI. Those with experience may not agree, but caution is
advised by MOPAR Performance. You may have to make radical changes in the existing
system to get it to work. Further, you need at least 12 inches of vacuum to get the
Chrysler EFI to perform correctly. Radical cams, along with the M-1 manifold will
lower the vacuum at idle and if it goes below 12, you are in trouble. I see one
message from a person who is running 10, but he has admitted to some problems.
Modification of Magnum heads is a NO NO according to MOPAR. If the heads make too
much air, which is intended, the EFI will not be able to read. I can attest to that.
That may be why no one can find a reliable head modification business that will do
work on Mopar Magnum heads. Unless you go to a carburetor, or radically change the
EFI system to a digital from ACCEL you will experience major performance impairment
if you modify the heads.
To my thinking, this means you cannot do much to the Mopar engine, other than NOS or
SC and there are problems with these. I have the SC and like it but there are
problems.
I also have heard 3rd person accounts of success, but no actual first hand info. I
sure would like to nail this down. It may save some people a lot of money and grief.
Allen
Jon Steiger wrote:
> Bill Tierney was saying that he knows of a guy who supposedly put a
> crate motor adapted to EFI in his 4x4. (Ram, I think.) I've never
> actually seen it myself, but I'm hoping he shows up at the track
> someday; I'd like to see that.
>
> > being sold by Chrysler are not Magnum engines to my knowledge. I have heard
>
> Check out the MP Catalog. I'm pretty sure it says they're Magnum engines
> in there. 300 and 380 "Magnum" crate motors. They're also selling a
> Magnum short block now too.
>
> Mopar Performance is doing that now, so you don't have to worry about drilling
> bosses for the injectors any more. Its called the MPI manifold, and its basically
> the EFI version of the M1 single plane. Its a 4-barrel manifold, but it comes
> with an adapter plate so that the stock 2 barrel TBI can be used.
> They were supposed to be out by now; I think Frank H. is checking on their
> current status.
>
> -Jon-
>
> .--- stei0302@cs.fredonia.edu ----------------------------------------.
> | Jon Steiger * AOPA, DoD, EAA, MP Race Team, NMA, SPA, USUA * RP-SEL |
> | '96 Dodge Dakota v8 SLT CC (14.58@93.55), '96 Kolb FireFly 447 |
> `--------------------------- http://www.cs.fredonia.edu/~stei0302/ ---'
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