BCOWANWHEELS":2caf99ko said:
since classic inlines is all but gone guess I,ll try to find out what was the intended application for the 1.65 rocker arms hopefully adjustable also who could make the aluminum roller rockers Harland sharp ? also does anybody know the pushrod length with the cupped end and its application. my engine is a 4.1 250. although I,am new to ford 6,s I already miss c/I business
The early 1980's had Perfectune make alloy extrusion rockers braded as Yella Terra. These Australian rocker arm use:-
1) a differernt lifter (302 Windsor/Cleveland hydraulic lifters), with
2) General Motors Holden 1968-1970 model year (Monaro/Kingswood/ToronaGTR) 186S pushrods.
3) The system uses a variation on the early adjustable valve gear.
4) Since its an extrusion, its not as strong as a traditional steel rocker arm can be, and there is evidence that roller tips are of no real benfit.
Look at Chevy's modern small block...they don't have roller tip rockers, but do have long rocker ratios.
If you wanna copy backward late 60's thinking, go for it.
For the cost, you could design proper 100% US components for a lot less, and get a 1.73:1 rocker ratio.
If you want to use early 80's tech, and late 60's parts on a 50's designed engine to beat all the work that Ford Australia overturned with a 1.73:1 rocker ratio 1976 cross flow, that's your business.
I'm telling you that on an engine that breaths as badly as the 250 does, you need every thousanths of rocker arm movment and duration.
In the case of removing 125 thou of lift by putting in a zero deck 8 cc dish 255 piston...that won't help you amke power.
I'd presonally use the hugh 1/8" piston short fall for more valve lift, and forget about ideal zero deck heads. Do you want a proper 560 thou potential valve lift with 1.73:1 rockers that needs only 325 lift at the lobe, or 490 thou lift that almost hits your pistons, and too much compression?
You need more lift, more duration, more piston to valve clearance, and a more constructive approach to building power. Ford in Australia was using 1.73;1 rocker ratio sixes in 1976, and longer conrods in 1998, and that's why a little 4 liter engine can shut down a good 5.0.
In 1969, little 245, 250 and 265 Hemi engines with 1.7:1 rocker ratios were taking out 302's and 351's for 11 years in sedan racing.