2 months later, I got it started today, whisper, whisper quiet. I also replaced the scorpion stud mounted rollers with T&D shaft mounted rollers. My experience fitting these roller rockers with early GN1's for stage 2 block:
- Don't install T&D's onto GN1 heads unless you have the heads off or are planning to pull them off as the pushrod holes will need to be enlarged.
- Take the little tool T&D puts in their kit which is used to set the shaft height and drop-kick it in the trash.
- The bolts T&D supplies to attach the shafts are too long, tighten them before shortening them and you will rip the threads out of the heads.
- Install Comp Cams light checking springs in place of #1 valve springs.
- Place a couple of shims under the shafts, use a sharpee to mark the top of the valve, put the #1 intake valve on its base circle, install an adjustable pushrod. Take the slack out by rotating the pushrod, when all slack is taken out you are good. Now rotate the engine a couple of times. Remove the rocker and check the pattern on the valve. If the pattern it is not in the dead center of the valve, raise or lower the shaft with shims as this determines where on the valve it will push down (ie: geometry). The T&D calculations and that tool are BS, you must check your geometry. Once that perfect geometry is found verify all valves are at the same height and that both heads read the same. Check the exhaust valve also.
- Measure the pushrod, add .035 to the measurement and call Trend pushrods and order 5/16" diameter with a 210 degree cut on one end and you are good to go.
- Be careful with the rocker adjustment screws, cannot turn it more than 1 turn from factory setting.
- When pre-oiling verify every rocker has oil pouring out over each valve.
Shaft height determines geometry, raise or lower it to center the roller over the dead center of the valve (sharpee method). Screw on the rocker is only for setting pre-load, do not use it to make up for pushrods that are to short or too long. Do not just set the shaft height according to T&D's instructions and roll with it, you must check the action on the valve. Going by the tool my shaft height setting was .050 too tall.
- Anymore than 0.010" clearence between the head pushrod hole and the pushrod is wasted effort according to Manton Pushrod company.
- If I had to do it again I would not torque those 7/16" ARP bolts to the heads, I would set everything up and get it right then determine what stud length would work, torqueing bolts into aluminum heads is a disaster waiting to happen, studs are much safer.
- The part that the shafts bolt to has play in it due to the bolts that hold it down. I had to bias mine toward the intake as far as I could push it.
- Install RJC spacers, clearence as necessary with die grinder to clear pushrods. I had to use these to get the valvecovers high enough to avoid hitting the pushrods.
It was a hell of alot of work but damn is sounds like a nice and quiet stock engine.
Mike