RE: 325ci Cobra small block

[slither]

At 6:10 in the recently posted YouTube video from Peter Klutt/Legendary on the Flip-top, there is a picture of a letter from Ray Geddes regarding using the car for testing multiple engines, including the alloy 390 and the iron 427 amongst others. One of those other engines was a 325ci small block.

I have looked around and did some searches here, but cannot find much of any info on it. Is there a good reference on that particular engine and its specs, like bore and stroke, etc.? Did it ever see use in racing?  Seems I have a vague recollection that Gurney raced it... 

Any tips are much appreciated!

[pbf777]

    It seems most of the references I've come across of the "325 C.I.D. engine" was that it was "under development", seemingly to be suffering from "reliability" problems, and yes it saw some actual race participation, but perhaps was most often deemed as a "secondary standard" under development, with some trepidation.   

    Not that I have come across any specification data as produced by Ford Motor Co. or Shelby American stating what the actual bore & stroke was, or that there was only one possibility attempted, but I'd probably believe the the bore was the standard 4" coupled to a crankshaft stoke of 3.25", which actually equates to something over 326 C.I.D. closer to 327 C.I.D., but since Pontiac had a "326" and Chevy had a "327" I guessing the Ford guys just settled on the "325" moniker?

     The other possibility might be with the bore at 4.030" (aka. "thirty-over) coupled to a crankshaft stroke of 3.200", which would result again into something just over 326 C.I.D..  It would come down to which issues the engineers were more concerned of, "stroke length" or the "over-bore", each bringing to the table drawbacks that could lead to problems? 

    Hopefully someone else can add to the meager information that I have, as I too find this an interesting subject!   

    Scott.

[kranky]

The Gurney Lotus 19 at Daytona 1965 ran that particular engine...ran as the "rabbit" to burn out the competition.  Dan Gerber is also noted to have run that engine in his Peregrine Special (ex-Bob Johnson car).

[slither]

Interesting info. Thanks for posting, guys! Anyone else?

[pbf777]

The Gurney Lotus 19 at Daytona 1965 ran that particular engine...ran as the "rabbit" to burn out the competition.

    Yes, I had read that somewhere; and that the "325" had obviously been selected for it's performance advantage due to it's greater capacity, but also as this presented an opportunity for further testing under the conditions stipulated, and then that they didn't really expect nor really intended that it would last the duration.   

    Scott.

[Vernon Estes]

Shelby American also ran 325ci cheater engines at certain tracks in the R Models and probably Group 2s as well. These were 289hipo based engines.. different from the DOHC stuff.

I believe they were run at circuits where tech was not as evasive and they put out a bunch more power and torque, obviously.

Interesting to hear that SAI did some testing of this engine in 2196. I have never seen a photograph of the car running that engine but I suppose anything is possible.

Kind regards,
Vern

[68stangcjfb]

I recall reading something about that engine in some book a long time ago. I can't remember the book, but I vividly recall it showing a picture of the connecting rods. I remember the picture because the rod caps were at a 45-degree angle as opposed to being flat across.

[JohnSlack]

The late Wayne Richards had a block and a crankshaft from the 325 program. The main journal were a different diameter and his was set up for the "Indy 255" rods. He had no pistons and he had bought the parts from the Shelby sale when they closed down the airport facility. He had offered them to me for a possible build for my BOSS 302, however at the time I was still hunting SK parts.


John

[csxsfm]

When I was young and following the the performance of the Cobra Team, I recall a disappointing race report from a west coast race where all the usually reliable factory cars blew their engines. I believe the report said they were experimental "325" engines. Should be some documentation around.

[kranky]

Daytona Beach Morning Journal....Photo caption-Disgusted Gurney--Dan Gurney pokes around under the hood of his Lotus Ford after retiring from the race with a burned piston.  He led all but 10 of the first 213 laps.

So there was some durability to the engine after 700 "+" miles of racing, not including practice mileage.

[Vernon Estes]

interestingly, i have seen factory dyno sheets for the 325 engine and the particular engine that the sheet recorded made just over 360hp and 360tq. In comparison, a full race, weber'd Cobra engine made 388hp but only 320tq

[camp upshur]

Peculiar. This 325 cu in hp/tq interplay is way off (by being the same) for a 90 degree presumably hi-perf V-8 (as opposed to say an agricultural pump-motor).
Although it could be many things, most initially look to an intake tract/ cyl head restriction, especially if/when the tq is in an 'expected ballpark'.

[pbf777]

    Not always does just increasing the engines' capacity result in more H.P.; but it does most often create greater torque numbers. This is as you are perhaps successfully transforming a smaller capacity, higher R.P.M., automotive "performance" engine, into what amounts to a larger capacity, but lower R.P.M. capability, truck or tractor engine!   

    If considering the rather conservative nature in flow capacities of the "S.B.F." inline-valve cylinder heads, this including the "C6FE" castings, and noting that this has always been a problem for allowing greater H.P. from these engines, one should realize that at some point the engine's volume capacity is going to out-run the cylinder head port flow capability (and camming) and at that point any gain in horse power at R.P.M. just isn't going to be had, even possibly reduced with the lower R.P.M.'s at which the engine might reach it's peak. 

    But again, torque numbers across the board (until the limited air flow kills the upper R.P.M.'s) will be up, and in a suitable application, even with less peak H.P., the greater torque can produce faster lap times.   

    Scott.

[tinman]

I recall reading something about that engine in some book a long time ago. I can't remember the book, but I vividly recall it showing a picture of the connecting rods. I remember the picture because the rod caps were at a 45-degree angle as opposed to being flat across.

I remember this also in a Super Ford Magazine article in the early 80's. They did an engine build and put it in a 66 GT350H.
Mike