Ford GT40 4 cam 255 indy engine

The photos above were sent to us by Todd Wertman in response to Bill Force’s comment at bottom looking for a ford 4 cam engine for a restoration project.

For use at Indy in 1963, Ford prepared a special version of the recently introduced 260 CID engine (small block Windsor V8). In stock form this engine produced 157 BHP. After an extensive series of modifications, the final engine displaced 255 CI and produced 376 BHP with good durability. Many parts were replaced with aluminum or magnesium to trim the weight down to 350 lbs. While impressive for a hotrodded 260, successful competition at Indy in 1964 was simply going to require more horsepower. And to do this, the breathing of the engine had to be improved.

For 1964 a dual overhead cam version of the engine was produced. The block was cast of aluminum alloy, using patterns modified from the production 289. Cast iron cylinder sleeves were a shrink fit in the block, and were sealed at the heads with copper laminated steel O-rings. In order to clear the two banks of camshafts in the heads, the 10 attaching studs were moved in closer to the cylinder centerline. An additional 8 studs protuding from the heads maintained the clamping force needed to seal the combustion chambers. The space occupied by the camshaft in the normal production engine was replaced with an oil tube. This acted as a gutter and collected oil as it drained from above to keep it off the reciprocating assembly.

The bottom end was beefed up considerably. The special forged steel crankshaft was held by 4-bolt bearing caps on numbers 1 through 4. Main and rod bearing journals are the same size as the 289, as is the engine’s stroke – 2.87″. The rod journals are crossdrilled for better oiling at high engine speeds. The rods are from the 289 HiPo, having been modified for floating pistons pins. The pins are 289 HiPo pieces. The oil pan is cast magnesium and is a structural part of the engine as is common in Indy and Formula car design. Ears cast integrally with the pan provide the engine mounting points in the chassis.

The cam-ground forged aluminum pistons have a pent-roof dome to closely fit the combustion chambers. Compression is 12.5:1. The cylinder heads used 4 valves per cylinder with a central spark plug location. The plugs are canted toward the 1.64″ diameter intake valves. Exhaust valves are 1.36″ diameter. The camshafts run in bearing bores in the cylinder heads, directly over their valve banks. Valve clearance is adjusted by the selective fitting of the followers. Intake ports are between the cams, with exhaust out the top of the heads between the vee. This was done to do away with the nightmare of exhaust tubing normally required. Hilborn injection is used having been selected for its light weight and simple low-pressure design.

The complete 255 CID engine weighed 406 lbs. and produced in excess of 425 BHP at 8000 RPM while giving a fuel economy of 7 to 8 MPG. Maximum speed is 9000 RPM while the minimum useful speed on the racetrack is around 6000 RPM.

33 thoughts on “Ford GT40 4 cam 255 indy engine

  1. How many GT40s used this Indy engine???

    I’ve seen one on display before in an Automotive Engineering here in Tampa, FL.

    Nice engine! Rev it up!

    1. 4 cam never used by GT40. Ford concluded that when Shelby took over GT40 programme in 1965 that it was not proven enough for long distance racing so the quest for more power was realised through the use of the 427 engine while Shelby adopted the 289, which ultimately formed the main engine used in GT40 often in 302 form.

  2. We are looking fora 4 cam Ford Indy motor for a resotoration.
    Bob Harkey driven # 57
    Former Ken Brenn Car
    Thanks Bill

    1. Good luck with your search Bill. If anyone reading this can help then email me at mrrbob at gmail dot com. I will forward your email to Bill.

    2. Todd Wertman has responded to your request with an engine for sale – see photos at top – We have put Todd in touch with Bill and hopefully they can make a deal!

  3. In 1969 or 1970, I read an article about this engine, and it was claimed to sell for $20,000 at that time. I think I would rather have a SOHC427. Hell, I’d love either!

  4. Some one has contacted me with an engine for sale Bill, forwarding the info to you now. I’m also asking for permission to publish the photos he sent.

  5. I met a guy in the Tampa area of Florida about 10 years ago who had made an obsessive hobby out of collecting Ford Indy Quad Cam engines of both the N/A and turbo versions. He had 8 of them, brand new on pallets, shrink wrapped waiting to be sold and enough spare parts to build another 30 or so!! As I recall he also had the casting patterns and all manner of special tooling associated with these engines. I came away with my head spinning!

    1. I do not know of such an exhaust system for sale. You may want to check here – There are many GT40 owners and enthusiast from all over the world who frequent this forum. I suggest you sign up, introduce yourself and ask your question there. With so many members you may find some one who can help.

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    1. Not sure I understand exactly what you mean by this but if you like the post and the subject, I do understand that. Thanks

  7. Being of an age when the GT40 was raced..I am firmly of the view the 4 Cammer was never used in it in competition – nor was it even ever fitted by any serious users of the car. 1964 saw the GT40 have a promising, but otherwise unsuccessful season with the dry sump (60 lbs.weight penalty for that feature) 4.2 Indy push rod engine (Designation AX230-2) powered car. Failure of the car that year not being due to the engine. End ’64 saw GT40 development pass to US where Shelby and Ken Miles instigated many changes – one of them a change to 289 engine with wet sump. In parallel Ford opted to go to 427 engine (first appeared ’65 Le Mans).The ‘4 cammer’ never entered the equation.

    Re Exhaust on GT40 – Interestingly, according to a well documented book on the 60’s UK F1 Engine builders Coventry Climax (CC) they were asked by Chapman of Lotus if their V8 F1 engine (FWMV) Exhaust layout design could be provided to Ford for their AX 230-2. This apparently happened and Ford reported a 63 BHP increase as a result of the design adoption – one that was designed by Climax’s Walter Hassan and Gray Ross to improve exhaust gas scavenging. It helped CC with more power for their 1.5 litre V8 and as I gather aided Torque considerably. The layout of the pipes also was followed on the 4 Cammer though the exhausts exited from the middle of the Engine Vee in this unit.

    1. Now that’s some information ! Old enough to have seen GT_40,s race at santa barbera airfield in 1965 . Think shelby was sorting them out just off plane from Ford ,Nassau ? Were running 289,s I’m sure .they won Le mans a year later with NASCAR developed 427,s .Robert Yates was wrench for Holman and Moody .Bet thats who built them .!

  8. Jim (Smart), Such a book would be of interest to read….the era of these Ford Small Blocks is one when I was growing up (some may say that never happened!). I simply ‘lived’ through the period and saw some racing with GT40’s and attended as a spectator the 66 Le Mans where the small blocks hardly featured and if they did then they hardly covered themselves in glory. Mind you the sight of the Mark 2 427’s storming round the circuit together with the P3 Ferraris was a sight I will take with me to my grave.

  9. The real use of these engines in the form shown (unblown) was in USAC sprint cars. Although a few Indy cars used it, its real life was in the dirt. Al Unser won the 1970 USAC National Championship with one – it’s in the Unser Museum in Albuquerque NM along with the follow-on Viceroy car. The docent there told me that the Ford 4-cam powered cars were where Al Sr. lost his hearing. I believe there are 7 straight-cut gears on the cam and oil drive, which when running sound like an Allison aircraft engine – a high-pitched ringing sound, quite unique. When the motor was installed in the sprint car chassis, the cylinder heads almost touch the front wheel at full lock…..

  10. Does any one know if a Mustang was run on the Great Salt Lake with one of these engines??
    The reason I am asking is that in the 70s I saw one in Stockton and the kid driving it had no idea what it was, and yes the valve train noise was the same as I remembered from Laguna Seca in 1970. By the way that GT40 was being driven on the streets with a “Red” temp registration in the window!!

    1. Yes. It was featured in Hot Rod Magazine in 1967 when I was a kid. It was a “67 fast back. Mario Andretti drove it. If I recall it had solid front axle. The headers went thru the inner fenders. I think the story was that they burned a piston due to a clogged Hilborn injector and couldn’t make a return trip so I don’t know if it set an “official” record for at least one of their record attempts.

      Here is a link to some information about it. I still have the copy of Hot Rod Magazine from 1967 with the article in my garage somewhere.

      I don’t think it was sold to anyone. I believe it was a Ford Motor owned car. Later in life I worked as an engineer for Ford in Dearborn and most of the “special purpose” cars and engines were either dismantled (junked), re-purposed or sold to “reliable” associates such as Shelby, Holman Moody, etc. Since the 255 was not a prototype, it could have been sold to one of those. Or it could have languished in Dearborn until taking a final trip to Environ which was the FOMOCO secure junkyard. It used to break my heart when I would see old prototype engines being loaded up on a flatbed in the Ford EEE building for the final ride to Environ to be melted down. Some were quite unique. In any case that car and that engine were far from street-able so it is unlikely that it ended up in the hands of any private party.

      1. My Dad ran a 4 cammer at Bonneville in an extended 27 roadster. I’ll find pics of it and send. Got to 187mph before burning a piston. Engine built by Joe Boghosian.

  11. I saw a Chevy Chevette at Bonneville one year running what was said to be out of the 1970 “Johnny Lightning Special”, Al Unser’s Indy pole sitter and eventual winner.

    1. this great engine is the grand farther of all fords mod motors of today the best small block ever biult i know ihave many of them
      4.6 671 blown 4.6 8 stack injection 4.6 blown procharger 4.6 8 stack injected with F1 procharger

  12. Jim Toetsing, a serious engineer and a working consultant to the Cunningham Museum in California, very successfully installed a Ford 4-cam Indy motor in his GT40 (chassis P1027.) The car was amazingly steerable as Jim proved when we drove from the museum in Costa Mesa to lunch in Newport Beach.

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