GM HEI computer control

[Fran and Bud]

Don,
I think Howell Engine Developments can help you fit a TBI to your Pont.
(Told the same thing to an earlier post, week or two ago) They have a cast
adapter that is used to put SBC or even BBC TBI's on various Jeeps, motor
homes, etc.   

Their adapter is a two piece unit that places the TBI bores over the Q-Jet
primaries rather than over the secondaries like the plate that comes with a
Pro-Jection, so that rear of throttle plate(s) dumps near center of manifold
opening rather than at rearmost edge of secondary opening.  

Most, or at least many, manifolds have a dimension across the primaries
(outside to outside) that is similar to a Holley square opening,(about 3 5/8
in. as on a Torquer) while the equivalent dimension on a SBC TBI is 4.0 in.
(4 3/16 in.+/- on a BBC TBI).  The Howell bottom plate,is about 1/2 in thick
and tapers the 4 in dimension to the 3 5/8, when needed. (some aftermarket
manifolds have a thick/wide mounting surface around the primaries that can
be ground out to do the same thing, but many manifolds have only a thin, 1/4
in. or so, outline at the primaries and cannot accept a 4 in. opening.  You
can get the same effect by turning a Holley to Q-Jet carb adapter ($1 to $5
at most swap meets) upside down and backwards - that is square side down &
Q-Jet secondaries opening on top and forward. The Howell piece also provides
a balance slot between the two bores, much like a milled center divider in
the manifold.

The other piece,also cast aluminum, adapts the forward mounted TBI to a std.
4bbl Holley intake bolt pattern.  

It would certainly be worth a phone call to check it out, particularly if
you dont have anyone with a milling machine. (if you do find someone, dont
try to mill a 3 5/8 in. square hole unless he can also weld). A couple of
carb gaskets, (Q-Jet and Holley square), will help to visualize this and
make sense of what is otherwise just words.

Howell is at:
Howell Engine Developments
6201 Industrial Way
Marine City, Michigan 48039
(810) 765-5100  Phone
(810) 765-1503  Fax 

Bud
 
----------
>From: Don.F.Broadus at ucm.com
>To: diy_efi at efi332.eng.ohio-state.edu
>Subject: RE: GM HEI computer control
>Date: Mon, Dec 7, 1998, 3:21 PM
>

>I would like to use the stock Q-Jet intake 1967-72 but I would think the top
>would need to be milled out like a torquer intake, and I don't have any one
>that can do that. The reason I suggested a 1980-81 301 distributor is that
>it a drop in. If a 77 HEI is modified  The advance mech. will need to be
>locked at zero or locked advanced, I  don't know which one it is.  Good luck
>with your project .
>
>
> -----Original Message-----
> From: Jim Yeagley [SMTP:jimyeagley at stratos.net]
> Sent: Monday, December 07, 1998 7:54 AM
> To: diy_efi at efi332.eng.ohio-state.edu
> Subject: Re: GM HEI computer control
>
> <<Hello Curtis, fellow Pontiac fan. The only HEI that we can use for
>Pontiac
> EFI is one from a 1980-81  301 engine. Look for the 4 wire connector
>, pull
> the rotor off and as Bruce said there won't be any advance weights
>or vacuum
> canister. I plan to EFI a 1973 350 Pontiac using a 2BBL intake
>modified for
> TBI.>>
>
> Funny you should bring up Pontiacs.  My plans are for EFI and an
>overdrive
> trans in my '75 Grandville.  TBI will be my choice, as I'll have a
>friend
> machine me an adapter for the stock 4 bbl intake.  I also had the
>question
> of the distributor, so this thread is of great interest...
>
> Jim Yeagley
> Member:  www.indyram.org
>
>
>