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Oldsmobile 403 (Olds 403) Engine - Ask Anything

Ford Motor Swap
John Spiess via CarCraft.com:
I have a complete wrecked '05 P71 Crown Vic. I want to swap the front suspension, engine, trans, and rearend into a '75 Ford F-100 pickup. The fabrication work on the suspension is no problem, but what difficulties will I run into with the wiring and PCM? I have the complete car. Does anyone make a stand-alone harness that will work? I want to use the factory stuff for reliability and economy. Any information would be greatly appreciated.

Jeff Smith: We did a little searching and came across custom wiring harness conversions for two-valve Ford mod motors at Ron Francis Wiring. The company makes conversions for all the Ford mod motors up until 2004-of course, right? In '05, Ford converted to electronic throttle. We spoke to Scott Bowers, owner of Ron Francis Wire Works and the Detail Zone, who told us that they've been working on '05-and-later aftermarket harnesses, but the complexity of Ford's new system has made this a time-consuming effort. For the '04-and-older two-valve Ford mod motors, Bowers' system is a little different from most. He creates a box that allows you to individually wire in each separate sensor or control wire for the engine. The box also incorporates necessary fuses, relays, and other connectors and then the stock Ford computer plugs in to that box. This makes wiring the individual sensors much easier, and then you can route and bundle the wires in a way that best fits your vehicle.

I asked Bowers about retrofitting the '05-and-newer two-valve mod motors with an '04-or-earlier computer and running the engine with a cable-operated throttle. Bowers says he has successfully accomplished that conversion for a manual transmission-equipped system, but, again unfortunately for you, the '05-and-later automatic applications are far more complex because the new automatic transmission does not play nicely with the older electronics. So that idea is also not going to work. This leaves one of two choices for your truck, John. The first is to use the existing Ford OE wiring harness and computer. Bowers says the Detail Zone can work with you to do any necessary tuning and also disable the OE Passive Anti-Theft System (PATS) that is integrated into all the later-model computers. The other option is to sell the '05 engine and find an '04-or-earlier version, but frankly that's probably not going to happen. So it appears you may be stuck with the stock factory harness. It's tedious work, but you can extend the length of the harness if necessary to allow you to place the computer where you desire. If this is the plan, work slowly, do one wire at a time, and remember that each connection will need to be crimped using non-insulated butt connectors and then protected with shrink-wrap. You might also consider alternating the position of where you make these connections so as not to create a large bulge in the harness from all the butt connectors.

For others who may consider swapping a mod motor, Bowers suggests knowing exactly which engine you have (or are about to buy) so that ordering the correct harness will be less stressful. According to Bowers, Ford used two types of fuel injectors on the mod motors. The early EV-1 injector uses a rectangular wire harness plug, while the subsequent EV-2 injector employs a smaller, oval wire plug. The next biggest issue is deciding upon the fuel delivery system you want to use. The factory mod motors employed a single fuel line from the tank to the engine. While this can be retained, Bowers says the factory pump is difficult to adapt to earlier fuel tanks, and that can easily drive up the cost of the conversion. The alternative is to build a return-style fuel system using a vacuum-modulated mechanical fuel pressure regulator that can alter the fuel pressure based on engine load. The Detail Zone instructions call for an idle fuel pressure slightly lower than the 43 psi needed at WOT.

More Info
Ron Francis/Detail Zone

Chester, PA
800/292-1940
RonFrancis.com

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65 comments
Charles Nott
Charles Nott

I have a stock 1/2 worn out 70 455 w-30 in my jet boat. It still hauls. wish I could upgrade with a edelbrock top end and rebuild the bottom

Bill McBath
Bill McBath

I had this in my Nova for one last race before I retired, what a ride it was... Thanks to all my fan's ans supporters through the years.... The Raceway Hugger ---- signing off...

Thumper Stahr
Thumper Stahr

To me, Olds is second only to Pontiac. I love these engines.

Nathaniel Green
Nathaniel Green

Yup!!! Ev er since my lon.g gone 87 307 beat a mustang gt more i.nterested in burning out than racing. That 403 deserves to go into an oldsmobile. I suggest you guys dig up a late 70's cutty or something for it.

Herb Edgell
Herb Edgell

joe mondello is your olds power guru.

Jeffrey Roseling
Jeffrey Roseling

I got a 78 olds delta with a 403 runs good with 250,000 mile on it and never rebuilt

Larry Fogle
Larry Fogle

It pisses me off when they put a Chevy in anything that is not a shevy keep the Olds and make her run.

Christopher Shipes
Christopher Shipes

My Dad has a 403 olds in his 79 Pontiac Trans-Am. We still have to redo it. Haven't had the time or money to get it right.

Chris Welch
Chris Welch

Definetly, i had an 81' Olds Cutlass with an Olds 455 in it. That was a fast car, I wish I had it back.

Travis Kerns
Travis Kerns

Build a 455 race motor. Up to 500ci. All motor. Naturally aspirated.

Michael D Taylor
Michael D Taylor

403,307...... run for ever...R.E. Olds would have liked them.

Greg Reinarts
Greg Reinarts

With the added strength of H-beam rods these engines can now be run hard and make lots of torque, and you can find them in self service wrecking yards at bargain prices.

Shawn Dumas
Shawn Dumas

Damn! My first car had that engine they have power yes!

Scott Myers
Scott Myers

Yeah I need one for son's 79, its .030 over, ported heads, forged pistons, Compcam, and a 175 shot of nitrous..

Chip Wilson
Chip Wilson

I've used the Olds engine in a Camaro swap before, fits under the hood better than a Chevy engine and is a lot torquier. Also used the Olds engine in several Chevy pickups.

Marty Decker
Marty Decker

Had a 330 with a power glide in a 66 cutlass ran that thing forever. Pigtailed a pushrod one time was running 100 MPH in 1st gear installed a new one and she was running like new again.

Chad Bauer
Chad Bauer

I had one with a mild build in a 77 buick lowrider. It had no problem roasting those little wheels.

Frank Mahon
Frank Mahon

Big Olds freak. Just put a stout 66 330 in my 87 Cutlass Salon...have a 71 455 on the stand for teardown.

James Motor
James Motor

I'm a olds freak!!! Blaaaa!!! Yeah I had a 403 that was bad as hell !!! Dounuts for dayyyys!

Damon Stickney
Damon Stickney

I have a 403 .030 over in my 85 el camino and a 425 .030 in my 1976 cutlass and they both scoot down the road quite nicely Thank you

Doug Burks
Doug Burks

Love Oldsmobile I've had several olds torque monsters just like Buick were most everyone will bash and say Chevy is better I've had both they are all good but I like not being in the majority

Lee Atkinson
Lee Atkinson

GREAT motor for the street, super-easy to make into a 13-second daily driver. Not much harder to get into the 12's.

Zach Knouse
Zach Knouse

What's the deal with the gold edelbrock valve covers?

Greg LeBlanc
Greg LeBlanc

Olds 455 in my 1975 olds omega, bast to drive!!

John Royal
John Royal

I am just finishing up one for a customer

Aaron Lancaster
Aaron Lancaster

Lol not a 403. I have one in my Trans Am, I wouldnt give a plugged nickel for. It's going in the trash as soon as my big block chevy is done

Dennis L. Young
Dennis L. Young

I had a 77 Olds 98 Regency with a 403 it was to heavy to get off the line fast , but it was a cruiser on the open highway.

Jeffrey Ralph
Jeffrey Ralph

Hey I got a 383 stroker small block chevy in Chevelle what's a good set of headers???

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