BCOWANWHEELS":2wxtwhf5 said:
personally for a d/d usage I,d prefer the iron rockers. but for race applications aluminum would be better. keep in mind if you go past 1.6 ratio your gonna have to run longer valves , different valve springs plus more mods. gets real pricey quickly
Sure does. Great thing is though, your totally on the right track. The valve spring and valve quality allows you to use non roller tip high ratio rockers, and still get huge increases in torque and power.
Everything changed when Ford decided to
copy the porcupine Mark IV Mystery Motors 1.73:1 Chevy head and rocker arm pivots during the Knudsen era. Lee Morse was working on the Tunnel Port 289, a true G code thumper that used modified end supported Y block 1.6:1 rockers like this. Ford just decided to use the 351C heads instead to conquer the DZ 302 CrossRam Z/28. The FE valve gear was then left behind for ever, and it has been left to FE hardliners to do the work that Ford decided to opt out of. It was a comercial descison to follow the canted valve route. Based on the economics of chamber design and emissions from what Ford and Honda learned together in the late 70's, it was the wrong one. Wedge heads a re very cheap, very efficient, and the rocker gear pays for itself in durability.
In the days befroe titanium valve springs, they rocker shaft and rocker weight made rocker shaft engines spring surge prone. The big FE 427
just coped with things in a 7000 rpm Le Mans or NASCAR environment, but not in the 9000 rpm the Tunnel Port ran to.
The Boss 302, 335 and 385 engines could cope with a Super Cobra Jet cam grind, and the whole reason the engines in race settings ran side oiler porting was that the canted valve engines would shear valve springs when oil flow was restricted. So they just drained of the oil and kept the valve springs soaked.
Lee Morse was the Godfarther of proper valve gear development. The fact that the Tunnel Port was not put into production was Fords slight of hand...they 289 block of that era is what all 5.0 Windsor OHV engines are based on. The Tunnel Port was consdered a dead end, but it used straight Y block rocker gear, and reved to 9 grand.
This period Ford photo shows a Tunnel Port race head complete with the original rocker-shaft assembly. Former Ford engineer Lee Morse assisted with the Tunnel Port project despite a primary assignment developing the race version of the Boss 302, and explained that while the shaft assembly did a great job in terms of stability, high rpm and heavy valves played havoc with valvesprings (titanium valves were on the verge of debut).
Where things were headed PRIOR TO 1969 was independent runner engines with FE rocker gear, like the Gurney Weslake OHV cylinder head for the GT40 305 engines. This was copied by Dodge for another Indy project engine, which was probably why Ford opted out of rocker shaft engines for the US. Except for the Eurpean Touring car wining Colgne RS 2600.
Thomas #717's were 1.6:1 aluminum/magnesium items like this back in the day.
Be nice to see someone make some money from speed equipment, not a loss.
