Jeep 258 Conversion

[Shannen Durphey]

> Date: Mon, 4 Oct 1999 20:46:17 -0500 (EST)
> From: Mike Comai <comai at expert.cc.purdue.edu>
> Subject: Jeep 258 Conversion
> 
> I am new to the list as well.  I have recently been looking into an
> upgrade for my AMC 258 I6.  It has become clear to me that the only way to
> economicly do it is to do it myself.  I have looked into Howell's kit and
> it looks pretty good (aside from the $1k pricetag).  I called up and tried
> to order just the GM -> AMC intake adapter and they would only sell it to
> me with their "harness" and PROM.  Here is my 1st question - They charge
> $350 for their harness and I asked them why it was so expensive they said
> it was due to the filter for the RPM sensor.  What is the signal needed at
> the computer and what kind of conditioning would I have to do to the
> signal off the negative side of the coil?
> 
> I also plan on getting an adapter machined (unless there is a better way?)
Maybe there is a better way.  Look for Holley's website, look for
service parts, then look for the adapter.  If your AMC uses a Ford
style distributor, I've seen claims that the GM module can be driven
off the Motocraft pickup coil.  This might eliminate the special
filter.  

> but I don't know how crucial the design is.  My thought was to take the
> shop the old Carb and the new TBI and have him machine me a 1" thick
> plate, putting recessed holes for the plate to manifold mount bolts and
> threaded holes for the TBI to plate mounts.  How crucial is it to taper
> the TBI hole to the manifold opening?  Are sharp edges ok or does it need
> to be smooth?
What is the present carb (1, 2, 4bbl)?  What type of tbi are you
looking for (1,2,4bbl)?  Look for Jason Weir's web page.  He's
converted a Jeep engine to GM TBI.  If you look in the DIY_EFI
archives there may be some good info.
http://efi332.eng.ohio-state.edu/diy_efi/

> 
> Last question is about the PROM.  I will probably eventually write my own
> prom but initially I plan on using the prom from a 4.3L GM donor (post
> '87).  Will it adapt to the 4.2L AMC motor ok?
> 
> I would appreciate any help and suggestions for improving my approach as
> this is a new thing for me.
Again, look at Jason's page.  He's got some good firsthand experience
with a similar project.
Shannen
> 
> Mike Comai
> 1979 Jeep CJ-5
>