quote:Originally posted by "72 GTS:
Right,
Is there space enough in the Pantera engine area ?
I don't know. I never ran this set up. I am using Ford A3 heads with 180 degree headers.
The modification raises the header location 1". I would think that it really is an issue with using one of the stock headers with the modification.
It would move them up 1" and out 1". You might encounter difficulty with that?
Personally I think it isn't worth the effort and expense.
As George mentions, durability is going to suffer.
The aluminum bars are held in place with dowels on the bottom and extended head bolts on the top. More likely head studs.
I know that head studs on a Pantera are difficult to use because with the engine in the car and removing the head to service it, the studs make that difficult, if not impossible to do with the engine in the car.
I personally have never known anyone who has used the modification.
It was far more common to use is drag racing in 72 or 73 then Professional level road racing.
You would have to check the rules you were running under to see if it was allowed.
On a 500hp engine , I would take a guess and say it is worth about 25 to 30 hp over a certain rpm where exhaust flow is significant.
Bud Moore was the only one that was building 351c road racing engines that I can think of although probably Jack Roush was too.
I don't know if the NASCAR engines used the modification either.
I've never seen a set of modified heads from a race car being offered for sale. Chances are they would only last for one or two races and then crack.
The aluminum doesn't supply any structural support to the heads where the iron has been machined away and the angle of the cut would encourage a failure through it.
While I am on the subject of racing with the iron 4v heads, there was an issue with valve spring failure in long races like the 500 mile races NASCAR ran.
Eventually it was determined that the springs were overheating and failing.
The fix for this on the IRON heads was to spray oil on the springs to cool them.
The Ford MOTORSPORT high port aluminum heads were cast differently under the valve covers.
They were made to pool about 1-1/2" deep of oil against the valve cover, essentially submerging the springs in oil.
I don't think special iron 4v heads were ever cast like that to fix the problem. The Boss 351 production head configuration, as far as I know was the basis for the race head too?
Whereas the 289/302 Ford Windsor head had a special racing iron head cast for it incorporating changes necessary for racing the production head did not have.
At first that was just called the "heavy duty head", but shortly was changed to the "GT40 head" and had a C6FE casting number.
For a time Ford Motorsports, now called Ford Racing, offered valve covers for the Cleveland with the spray ports and nozzles built into the covers.
I have only seen them advertised once and never seen a used set offered for sale anywhere since.
Probably the NASCAR teams made their own.
I know there was a -3 or -4 exterior port to attach an exterior oil line source to. I can't find any pictures of those anywhere. Perhaps George can help on those?
I can anticipate a lot of people questioning that now but it you look at the ORIGINAL Boss 351 valve covers, inside they had sheet metal drip tabs that directed oil to the top of the rocker arms. The hydraulic cammed Clevelands didn't have that feature.
I think these were on the Boss 302 valve covers also.
To me this is a Ford acknowledgement that there was additional consideration necessary to the upper valve train for solid lifter camshafts?
Getting specific details of the Detomaso Gp4 factory race engines now is a bit difficult and sometimes the details are sketchy.
The press didn't cover those details hardly at all.
You have to presume that the engines were built to the maximization of the rules?