Small block GT40 Cylinder Head Specifications

pintopete · 04-10-04, 07:12 PM

I am trying to find the specifications on the original GT-40 cylinder heads used on the 289's in the mid 60's. I have seen a pair once, but it was quite a long time ago and I was not able to obtain the info. I would really love to have the port volumes, chamber volume and valve sizes. Thanks, Peter. [img]/ubbthreads/images/graemlins/confused.gif[/img]

Kevin M · 04-10-04, 08:46 PM

Peter,

Try: http://phystutor.tripod.com/stang/engines/small.html , http://www.thecarsource.com/fords/en...289engine.html , http://phystutor.tripod.com/stang/engines/289hp.html , http://www.67mustangfastback.com/ , http://www.fordcobraengines.com/Stanghist_1.htm .

None of the sites are complete, but you can piece a lot of it together.

Kevin

Ron Earp · 04-10-04, 09:38 PM

You can also search for the Gurney-Westlake heads on the forum here too. However, the flow and design of these heads has been eclipsed with the modern performance Windsor heads from a variety of sources. The heads come up for sale relatively often but cost a far amount.

favgt40 · 04-10-04, 09:49 PM

Check with Jay Cushman. He has the correct Gurney Weslake heads for a small block GT40. 207-892-8141

Steve Toner · 04-10-04, 11:44 PM

I'm not sure the original heads were Gurney-Weslake. Ignoring the 256ci engine, the original 289 engines were the proven competition engines from the Cobra program. The Gurney-Weslake heads were used by JWA starting in 1968 (according to Legate).

The only specs I can find right now say compression ration was 10:1 and the engine made 380 bhp@6500 RPM. No indication of valve sizes or combustion chamber size (though you might get close if you assumed flat-top pistons were used and calculated based on the CR)...

IF they used the HiPo heads, those were 54.5cc chambers with 1.78/1.45 inch valves (per Reid & Monroe)

Peruch · 04-11-04, 02:25 AM

C6FE heads,58cc,1.88 IN,1.625 EX

Ron Earp · 04-11-04, 08:23 AM

And those ratings back then were gross SAE ratings too, so consider that in the equation too as the SAE net rating that we use nowadays would be much lower.

Steve Toner · 04-11-04, 11:15 AM

Ah yes, the C6FE heads are probably what Peter is looking for..

pintopete · 04-11-04, 07:32 PM

The C6FE heads are the type that I am talking about. Not the Gurney-Weslake heads. The heads that I am interested in may have been referred to as LeMans heads or GT-40. They would be cast iron and have 1.88 intake and 1.625 exhaust valves. The only quirk is that they were used in an application that was supported by Fomoco in 1964, so that would exclude the C6FE as a casting number. They seem to be a similar or the same head. If I told you the application you may be quite surprised. It is not a GT-40. I plan on visiting Holman & Moody next month to try to get some additional info. I probably could never afford these heads, but would like to try to duplicate them as closely as possible. That is why I am in the quest for port dimensions and volumes. The chamber volume may have been 42cc! I believe that is smaller than the C6FE heads. Didn't Ford play with the 260 cu in engine in racing applications prior to the 289? The data that I have lists the valve sizes (1.88/1.65) and the chamber volume (42cc). That is about all I have. The application also lists a connecting rod weighing 630 grams which may have been a Lemans rod. Any info is appreciated. Thanks, Peter. [img]/ubbthreads/images/graemlins/smile.gif[/img]

Kevin M · 04-11-04, 08:01 PM

Are you trying to duplicate the early 60s pushrod Indy engine? If so there is an SAE paper with some information on that engine.

Kevin

Steve Toner · 04-11-04, 09:17 PM

Kevin,

The Indy car engine (at least as used in the GT40) had aluminum heads.

On the other hand, it did have 12.5:1 CR, so would have had pretty small combustion chambers...

[img]/ubbthreads/images/graemlins/confused.gif[/img]

pintopete · 04-12-04, 01:38 PM

I'll tell you the whole story. I bought a 1964 Falcon Sprint about 5 years ago. I started to do some research about the history of these cars in general and found that in 1963 and 1964 Ford aggressively sponsored these cars as rallye race cars in Europe. They then were nicknamed the Monte Carlo Falcons due to their successes in the Monte Carlo rallye in Eurpoe. When the Mustang came on the scene in 1964 1/2 or 5 the Falcon was no longer the premier rallye car. It was replaced by the Mustang. The Falcons then were used in road racing and saloon racing and may have continued to receive some factory support. Mind you there were only 15 of these cars produced in 1964. They received preliminary work at Holman & Moody and then were shipped to London England where they received additional preparation for the rallye racing. There are 3 of these cars known to still exist. So, I thought it would be a neat idea to make a clone of the original Monte Carlo car and road race it in a historic class that does not require a documented race history. I then acquired the homologation papers that provide some specifications. During preliminary reading about the cars it appeared that they had a K-code or Hi-Po 289, probably the same as a k-code Fairlane. Then when you read the homologation papers you learn that the specs do not match a regular k-code engine. The valves are too big, the chambers too small and the connecting rods way too heavy. My thinking was that Ford (Holman & Moody) may have used the Lemans or GT-40 type heads and rods in these engines. The homologation papers list the heads as cast iron. The specs certainly would indicate that is the case. The cam listed has a Ford part number, but as of yet I have not been able to identify what it came out of (C2OZ-6250-A). Any ideas? Thanks, Peter. [img]/ubbthreads/images/graemlins/confused.gif[/img]

Mark Worthington · 04-12-04, 08:43 PM

Cool project, Peter.

No tech here, but I wanted to relay the story of my all-time favorite Formula 1 driver, Jimmy Clark. I remember reading that he campaigned Falcons and gained a distinct advantage over the field when he realized that he could lift the inside front tire so high that he could clear the curbs and give himself an entirely new racing line. Man, that guy could drive.

Good luck in your project.

Mark Clapp · 04-12-04, 11:14 PM

Peter, as you probably know the cam designation of C2 is from 1962. Not many V8s then so I'm thinking it could be from a Thunderbird 253(?) or 260 V8. Maybe some place to start, the OZ will tell the car.

Kevin M · 04-12-04, 11:44 PM

C2OZ translates: 1962 - Fairlane - Ford Division Service Replacement Parts. 6250 is the part #, and A means it was the first version (not an upgrade or changed part).

Kevin

Kevin M · 04-13-04, 03:58 PM

Peter,

You might want to check with Comp Cams. They sell "Factory Muscle" factory duplicate replacement camshafts for 60s engines. They have one that is a replacement for the 289 Hi-Po cam. They show the Ford part # as: C30Z-6250-C Which would suggest one year later (1963), third revision. They could probably tell you if this is the same as the previous year spec A version.

Kevin