Hi all!
I've seen a lot of post on Slant Six head, asking for different casting, aluminum head with bigger ports, special combustion chamber and so on, so I decide to pick this up and show you our "Slant Six A.C.T.C. Race Head" from a friend of mine, hope you like it!!!
First a little bit of history on the head. The "ACTC" ("Asociación de Correderes de Turismo Carretera" something like "Road Racer Association) is an organization that regulates several race programs, including "Turismo Carretera" were only inline Six cylinder engines run the competition, this being the oldest race asociation in my Country starting 71 year ago and of course our main event. Those engines were the Slant Six 225, Ford 188/221, Chevrolet 198/ 250 and IKA Torino 188/230. During the year they run on 4 litre basis and during the mid '80s they put the cubics donw to 3,3 litre. At this time this head was develop and specially casted to the ACTC, and they sold this only to the homologated racer of "Turismo Carretera" through their partsprogram. The 3,3 Litre Slant Six Race Engine used this head with a "906" Casting Block with a 91/92mm bore (BIG!!!), using a 170cu crankshaft, dry sump oiling system and 1 Dyno Weber carb. This engines will hold pretty well up to 8700 RPM running on Close circuits most of the time, shifting gears in the 5500/8500 rpm range. Pretty impressive!!!
Ok so here is a quick look at the head
As you can see this are extensivelly modified heads, since they were ONLY available to the Dodge Racers and for race only, all this heads had been, fully ported, polished and modified in the Oiling feed, wather inlet-oulet, shaft stands, combustion chamber ... ok, you get the idea. Now lets take a closer look.
Combustion chamber: This head were casted with this heart shaped combustion chamber, i mean that they were not welded and them machined again, thats a complete different thing. You will notice that the valves seat are way up on the chamber and later you will see that the shaft mount are also moved up, that allows the racer to use very aggresive cam lifts. I try to take pictures of all the possible angles for you to check, take a look
Here you can check the size of the chamber and seats (sorry folks no Verneir Caliper in inchs ... only milimetres)
The heads were casted to use special spark plugs, I thing that this kind of sparks are used on marine applications and speedbikes
Here you can check on the valve seat and ports. Take a look at the extensive porting & polishing that this head went through, and it's the bigest thing I ever seen on a Slant Six head!!!
Here is the external oil feed to the head (they use an external oil pum with dry sump). The stock oil vein looks like it has been chanfered, maybe because the move the head position over the block? Not sure about this
The casted-in shaft stands are machined away and they add this steel+aluminum stand to move the rocker assembly up to accomodate high lift cams.
The spring seat also has been machined larger.
Check the bronze valve guides (the intakes retain the seals)
Block to head water by-pass blocked
And to finesh closer look at the top of the head, as you can see it is painted on the inside to help oil return to the oil pan. Also check that it still uses the spark plug tubes, not like your later casting.
Here is the "ACTC" stamp
So pretty long post!!! But I think is worth.
Martin
Do you have any flow numbers? It sure looks nice under the valve. That bowl is smooth and quite different from what mine looks like. Certainly no valve guide bulge to get the flow around. And how many were made? Can they be bought or are they like hens teeth. Thanks for sharing. Definitely cool. 