[Gmecm] Looking for MPI/Conversion information for GM 454 CubicInch Engine

[Eck, Joel]

Boat motors were available with multi-port EFI back in the early-mid '90s; that makes them pre-vortec; Mercruiser MPI in 454 Magnum and 502 Magnum flavors. Problem there is, "boat" makes it cost more than aftermarket parts. Checked ebay and that confirmed my analysis.

There were also the 'ramjet 502' crate motors that came with MPFI.   Either system would probably be equally difficult to find laying around somewhere unused, although not completely impossible.

Even at that, I think (in both cases) it was the Gen V big block  - I'm not well enough versed in BBC-ese to know if those manifolds would bolt up to a '73-ish Mark IV BBC.

I think David's got the right idea for the big parts of the hardware - drill and fabricate.

From: gmecm-bounces at diy-efi.org [mailto:gmecm-bounces at diy-efi.org] On Behalf Of David Allen
Sent: Wednesday, September 14, 2011 11:54 AM
To: Adrian Flynn; gmecm at diy-efi.org
Subject: Re: [Gmecm] Looking for MPI/Conversion information for GM 454 CubicInch Engine

Adrian, glad you're considering an EFI retrofit!

One major thing to watch for, is buying all parts from the same donor vehicle. I've run into issues with imcompatible parts, missing small items, and various other 'gotcha' issues when the donor vehicle is not available, or parts have been ordered from here and there.

Have you considered a TBI?  It is mosty the same, electronically; but the unit is simpler to install. I know for fact there are 454 TBI manifolds, but I haven't seen a 454 MPFI manifold.

You could easily bolt on a TBI manifold and wire everything up and it would run without any real headaches.

If you want multipoint injectors "just beacause" (which is fine here!), the electrical install will be basically the same; but you may have to build a fuel rail, drill the manifold, and of course the tune will be a completely custom job.

Sincerely
David

----- Original Message -----
From: Adrian Flynn<mailto:adrianjamesflynn at gmail.com>
To: Gmecm at diy-efi.org<mailto:Gmecm at diy-efi.org>
Sent: Tuesday, September 13, 2011 2:27 PM
Subject: [Gmecm] Looking for MPI/Conversion information for GM 454 CubicInch Engine

September 13, 2011
Hello to everyone,

I have been setting in the background reading the posts and trying to make sense out of them.
I am about to get my feet wet (as it were) with my 1973 3/4 ton Suburban. 4X2

What I want to do is add Multi port Injection in place of the Carter/Edelbrock Carburetor that is currently powering it.

I would like some pointers in the right direction as to what I will need to do to accomplish this.

What I would like to do is acquire a complete GM system from a junkyard 454 (Yeah I know Headaches),
My main reason for doing this is that I am living on a Disability income and don't really have the coins to
buy a NEW unit.

Electronics was my lively hood for over 35 years as a repairman of TV's, Stereos, Microwaves ETC;
so computers and such do not bother me and I have the tools for servicing them.
Only thing I do not have is Scan Tools for Automotive Computers, OBD_I & II etc.

I know this is reinventing the wheel but I hope to be able to get the information I need to do this., and what pitfalls to avoid

The Suburban is a factory 454 with the turbo 400 Transmission, it is equipped with long tube headers, dual 2 1/2 inch cherry bomb exhaust.
I will be upgrading the Transmission to a 700R or 4L60 in about a year or so.

The Suburban does not have a Cat on it (Missing when I bought it in AZ) but don't mind putting one on if need be for best usage.

My goal is best fuel mileage possible, with maximum low end torque.
I WILL NOT BE RACING IT!
I may be towing with it from time to time a trailer that grosses out at 12,000 lbs.

I use to have a 25' Sports Coach on a GM Chassis with the 454 and I averaged 15 MPG when I was not towing a Ford E150 behind it, with the E150 I averaged 10 MPG.


OK, I probably have bored you enough but I like to try to fill in the basics of what I have and plan to do when asking questions like this.

I thank you for your time.

Adrian Flynn KF7DYU

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