Converting a Mopar 440 to GM TBI translated

[Shannen Durphey]

Don't forget the little 2.8 tbi.  It's got reeealy tiny bores.

The tbi used on the 454 is small for the engine's size.  Using something smaller
still would reduce the overall power made by the engine.  Your 440 may truly suffer
if you were to use a tb sized for a small block engine.  The actual hp rating of
the tbi 454 is around 220.  With a 350 sized TB, you likely won't draw enough air
into the engine to generate numbers that high.

One option is to find someone with access to a machine shop and see if you can get
the throttle bores machined larger.

There are adapters available from Holley and GM (and maybe others) which will allow
the throttle body to be bolted to a 4bbl manifold.  The GM part is fairly spendy if
purchased through the dealership.

You migh consider using a Chrysler electronic ignition distributor with a GM
ignition module.  You will need to permanently prevent the vacuum and mechanical
advance mechanisms from moving in order to take advantage of the ecm;s ability to
adjust spark timing.

Beyond any doubt, the best ecm to use is the 1227747, which was used in most 8 cyl
tbi pickups, and some 4.3 v6 applications.  Search the gmecm home page, there's a
ton of info about it, and there are many free tools to help tune it when you're
ready. 

Cadillac tbi systems can have subtle differences from other GM systems.  Sometimes
they have no IAC to control idle speed, but use an external motor to open the
throttle.  This scheme is not designed to work with a "regular" GM tbi ecm.  I have
not heard of anyone adapting the Caddy system for use with a 7747 or one of its
cousins.

Download and look through the diy-efi archives.  There are plenty of war stories
and more than a few different versions of this same question there.  You'll find
more information than you want to know, and you'll probably end up with a few new
ideas before you're done.

But by far, the best answer for the simplest swap is to locate a complete TBI
equipped 454 and get all your parts in the same place.  Any other option involves
more time, effort, and research.

Shannen
My clock says 8:36pm...

Jove Malcolm wrote:
> 
> as a real quick answer, theres two major TBI units gm made. one was found on
> the 4.3's and 305's and 350's. flows like 500cfm or something around there.
> Then there is the bigblock TBI unit, with 2" butterflies. this is what all
> the aftermarket units are based on.
> ----------------------------
> Jove Malcolm / TheDrip
> drip at home.com
> ICQ: 6778499
> http://www.sendon.net/~drip
> 1989 Chevy Blazer
> 1980 Pontiac Trans Am WS6
> 1960-1990 Combined pile of rust
> approximately the size of a vehicle
> 
> ----- Original Message -----
> From: <ECMnut at aol.com>
> To: <gmecm at diy-efi.org>
> Sent: Wednesday, March 07, 2001 7:08 PM
> Subject: Re: Converting a Mopar 440 to GM TBI translated
> 
> > I want to install a GM TBI system on my
> > 1978 Dodge motorhome with a 440.
> > I think that something similar to what
> > was used on a 454 would work pretty well.
> > I am trying to pinch pennies so I do not
> >  want to spring for a setup taken
> > directly off a 454.
> >  My brief research
> > seems to indicate that there
> >  was only one GM two barrel throttle
> > body made,  the model 220, which was
> > used on everything from V6's to 454s.
> > I want something close to what was used
> >  on the 454 but fuel injected 454 components
> >  are not available at the price I am willing
> >  to pay.
> > Could I get the throttle body from, say,
> > a Cadillac 4.1, add injectors designed for
> > a 454, use the harness, computer and sensors
> > from a 4.3 V6 or 2.8 V6, distributor from the
> >  Caddy 4.1(modified to work on the 440)
> > and be ready to rock and roll? It seems that
> >  I may not want to use all of the Caddy 4.1
> > setup because it is Digital Fuel Injection.
> > I have installed a 1988 Mustang 5.0 EFI motor
> >  in my 1983 Mitsubishi pickup complete with Mustang
> >  rack and pinion steering and a disc brake Dana 44
> >  from an Isuzu Trooper. I know this conversion
> > involves the four letter word F-O-R-D but it
> >  does work pretty good.
> > I mention this mainly to indicate that I am willing to
> >  modify things to make them work.
> >
> > Let me know what you
> > think if you have the time.
> > Brian Roth
> > broth at sanjuan.edu
> > --------------------------------------------------------------------------
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