Theres the answer! its in the heads, normal windsor heads just dont flow enough to get big horsepower but with these vastly flow improved heads its easyily achieved. Ford,s 1968 289 SOHC windsor was abandoned at 300 hp as the heads just didnt flow enough to benifit from the OHC conversion.

  AussieBill            YYYY    Forever Y Block     YYYY

 Down Under, Australia

I guess your going to make me do some research. This article is claiming over 500hp but I know there is one I read somewhere where it was up near 700 on some of his developements.

1967 Gurney-Weslake 305

The new heads, cast of aluminum alloy by Alcoa, did evolve. The intake ports were a short shot, leading directly from the carburetors and aimed straight at the combustion chamber. No intake manifold is used. The Webers bolt directly to the cylinder heads. Steel valve seats were used on the 2-1/32" intakes, and bronze on the 1-5/8" exhaust. Normal 45 degree seat angles were used. Rockers are shaft mounted with removable stands. Three different heads designs were developed, including one to fit under the stock hood of a Mustang.

"Actually, we began our inquest with extensive rework of the existing 271 hp heads.", said Dan Gurney holding back a smile. "At the peak of our testing with the 271 hp cast iron heads on a 325-inch block, we were pulling as much as 448 hp on gasoline. It was about this time we figured a few improvements along the lines of a new head design might give us even more power, so we got after it." Camshaft development was handed off to Jack Engle, ultimately settling on a relatively short-lift long-duration camshaft. Rev kit springs were placed between the lifter valley and the underside of the cylinder heads to extend the RPM range of the valve train. Both 289 and 305 CID versions were dyno tested. On gasoline, the 289s developed as much as 506 hp @ 7800 rpm. The 305s pushed 520 hp.

Not much remains of the stock 289 HP bottom end. The crankshafts were custom made by Dearborn Crankshaft Company. Bearing inserts were taken from the Ford DOHC Indy engine. Carrillo rods, super finished and shot peened were fitted. Stock 289 oil pans were chopped up and baffled for each particular type of track. Probably the most interesting modification was the addition of a main cap girdle. Even so, main bearing saddle cracks were common. Stock 289 head gaskets were found to work reliably.

55 Vicky & customline

58 Rack Dump, 55 F350 yard truck, 57 F100

59 & 61 P 400's, 58 F100 custom cab, 69 F100, 79 F150, 82 F600 ramp truck, 90 mustang conv 7 up, 94 Mustang, Should I continue?

700hp sounds a bit optimistic. Here's what I found with a brief search.



http://www.gurney-weslake.co.uk/



In that link, the allude to the 1968 and '69 GT40 at Le Mans.

http://www.supercars.net/cars/691.html

At just under 302ci, it produced 425hp. So either at 700hp, the engine isn't reliable for road racing. Or, I will cite occam's razor, and assert that it plain didn't make 700hp. If it did, I'm sure they would have made use of it and won more races.



Lawrenceville, GA

If you want to hear something unbeleivable, I read somewhere where the gurney westlake 289's were putting out like 700hp, thats more than 2hp per cube.

55 Vicky & customline

58 Rack Dump, 55 F350 yard truck, 57 F100

59 & 61 P 400's, 58 F100 custom cab, 69 F100, 79 F150, 82 F600 ramp truck, 90 mustang conv 7 up, 94 Mustang, Should I continue?

Personally, I would very much like to believe that it is true, as it would help lend credence to the supposed 362 hp my 292 makes (according to the guy who sold it to me). When figuring whether it was worth it or not, I subtracted 100 hp from that to make it more plausible...but who knows? I think the answer is less "380+ HP" as it is the definition of Streetable and "Good" mileage. And I would also have to wonder whether he considers a bored/stroked 289 still a 289...if you look at it not by original displacement, but by current, I have a 340.

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People should not be afraid of their government, a government should be afraid of the people.

--Alan Moore

A little more information has come out.  The engine is a .020 OS bore 289 without stroked crank.  Car is 1965 Mustang.  HP is not 383 but 393 (my mistake), 4100 jetting 51 primary 62 secondary, Heads aluminum Holman Moody, no power adders, with a 10:1 CR.  No particulars were given on the cam magic.

Mike, located in the Siskiyou mountains, Southern, OR 292 powered 1946 Ford 1/2 ton, '62 Mercury Meteor, '55 Country Squire (parting out), '64 Falcon, '54 Ford 600 tractor.

I think the power level is possible. It's only1.33hp/ci. Given all of the aftermarket products for a small block, that should be relatively easy. 89 octane, streetable, and good mileage is not believable. Of course, streetable has a different meaning to everyone. Actually, I take that back. Depending on the vehicle it's in, it cold be streetable. Even mileage is subjective. When you have a vehicle that got 10mpg and after modifications, it now gets 12mpg, that can be good mileage but when compared to other vehicles, it's not.



You can ask for dyno proof, but even then, proving that it's running on 89 octane will be near impossible. See if you can get him to fess up to anything else. Vehicle weight and gearing, put a number to the good mileage, etc.


Lawrenceville, GA

Mike i agree.. Considering the fact that the Carrol Shelby prepped and paxton super-charged K-code 289 in the GT350 made about 390HP this guys claim would be hard to swallow without a dyno slip to back it up (I bet if you ask him for it he "can't find it")

Dustin

Southern Oregon Y's Guy

http://www.facebook.com/?ref=home#/profile.php?ref=profile&id=1441322018

I was reading the Autolite/Motorcraft carb forum and noticed some performance claims made by a person and his 289.  383 HP on 89 octane fuel.  Engine is streetable and has good mileage.  Carb in use is a 4100 1.12 venturi worked over by Pony (600cfm). 

I was thinking no way, but then he could have some nitrous in the trunk that wasnt mentioned .

Mike, located in the Siskiyou mountains, Southern, OR 292 powered 1946 Ford 1/2 ton, '62 Mercury Meteor, '55 Country Squire (parting out), '64 Falcon, '54 Ford 600 tractor.