66-67 MkII/MkIV engine specs? What heads, etc. were used?

R

I've just finished reading Trevor Legate's excellent book on the GT40 and I have some questions about the 427 engines used in the LeMans cars fielded by Shelby American and Holman Moody. The book states that the '66 spec cars were using a 485bhp engine that weighed 550lbs. The '67 MkIV entrants had an upgraded 530bhp engine. The only other details I could find were that they used "aluminum heads" compared to the NASCAR 427's.

Which heads did these cars use? Were they the 427 "tunnel port" style or "high riser" heads? Did they all use single 4bbl Holley carbs? Any details on these engines would be appreciated.
 
T

Steve Toner

The Ford GT40 by David Hodges is not much help with respect to the heads either: he mentions "light-alloy cylinder heads" that "brought a useful reduction in dry weight"

According to Hodges, the MkIVs had twin Holley 4V carbs. But here is a photo of 1012's engine (the Don Davis one - you can read about how there ended up being two 1012s in the Legate book), and it clearly has Webers. Whether they are original or something Davis added during his rebuild I don't know.
engine.jpg

(photo taken in 1988)
 
S

OMeyer

About ten years ago I saw a set of loose 427 aluminum heads for sale at at the PFCA Super Ford flea market in Columbus, Ohio (price $2500 then). They bore "C7" casting numbers, as I recall, which indicates that they were first made in 1967. I was not previously aware that Ford ever used these heads in their domestic race car program and therefore always suspected that they were made for the GT40 MK II or MK IV efforts. In a previous post someone said that they remember some of the 427 GT40s at the track running 2X4s and aluminum cylinder heads, but I can't remember whether these were on MK IIs or MK IVs. Maybe others have more complete info or can check the old posts on this board.

[ May 06, 2002: Message edited by: BlueOvalBlood ]
 
M

Jim Glickenhaus

MK-IV's used iron tunnel port heads and two Holley 4 barrel carbs. Some testing was done with alloy heads but at LeMans the iron heads were used. I have a set of alloy tunnel ports "SK" first castings from the sketch but they were only used for testing.
 
T

Steve Toner

I knew that (that 1012 is a MkII). Bad structure in my previous response - I tried to answer two questions in the same paragraph.

OK, so for the record:

MkIVs had twin Holleys.

At least one MkII had Webers (though we don't know if it ran that way when Peter Revson drove it & crashed it
frown.gif
)
 
M

Jim Glickenhaus

On the street I use vaccumme to open the secondaries on my dual quads in my MK-IV. The red line is set at 7000rpm but I shift it before that as max torque comes at about 6500. The dry sump holds 20 quarts. I use 40W valveoline. Fuel psi is 7 lbs. (The Lucas mechanical fuel injection in my P4 runs at 125 psi! To start it you have to squirt fuel down the intakes)
 
G

Guest

Guest
Only direct experience I have was at the 66 Daytona Continental. Was a pit steward there.

Ford Mark II's arrived with aluminum heads and one 4 bbl. Engines were marked "E&P Experimental."

Practice showed they were a little slow in comparison with the Ferrari's (335 P4?) ... so they popped steel heads on them with two four bbls. Ran faster, but made more torque as well. The spent much of the night replacing half shafts. Turned out not to be a good idea.
 
G

Graham Endeacott

If you can get your hands on a copy of the SAE Papers, this gives a complete description of the heads used and the number of tests etc that were done to determine the final spec.
 
Neal

Neal

Lifetime Supporter
What an interesting Weber manifold. The linkage must be a bear...

Julian,
Ford has a number of small block alloy head options all less than US$1000 complete. Companies such as Brodix,Trickflow Specialties and Air Flow Research offer better flowing heads at a cost of $1000-$1400 a pair, complete.
 
P

Paul Bearman

Julian,

Sorry hit the wrong button.

I have a pair of Edelbrock aluminium heads which I have been reliably told provide greater performance over stock iron or Dart heads. They cost £890.

Regards, Paul.
 
J

Julian West

Thanks Paul, Neal,

Looks like there isn't much price difference between buying them in the UK or US (suprisingly!)

The weight saving alone must be worth it, & ally heads are 'more' original I guess...
 
R

<BLOCKQUOTE><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><HR>Originally posted by GT40Graham:
If you can get your hands on a copy of the SAE Papers, this gives a complete description of the heads used and the number of tests etc that were done to determine the final spec.<HR></BLOCKQUOTE>

Graham, any chance you know the "numbers" of those papers? If so I can look them up at the Texas A&M University engineering library (my alma matre) by the SAE number. I did this once years ago for an article from Honda on "high performance, small displacement" engines that was published in the late sixties.
 
C

Gary Gibbs

I have all the papers at home and will try to look up the numbers when I get home. Very nice reading. You can get them from SAE.ORG for $8 each.
 
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