I thought this thread was too good to bury in the first post so I brought it into the light. Nomad has some excellent info here...it's new news to me and I'm sure news to others also.
Thanks Nomad!
8)
pushrod is making contact with the pushrod tube on the front exhaust ..
.. front exh. is always the worst for this cuz of the angle .. if you have the S&S pushrods, the cure I'm told is to shorten the small (upper) tube by about 1/4" .. the reason is cuz the "too big to clear" locking nuts on the phat pushrod is clipping the bottom of the upper tube .. shortening the upper tube enough to clear will depend on the cam lift you run, but 'bout 1/4" is a good starting point ..
.. you might get a good idea 'bout how much to remove by kicking the motor thru while holding JUST the upper pushrod tube in place by hand to see what it'll take to miss the nut when that valve cycles thru ..
.. removing the spark plugs will make that easier .. if you have no kicker, you can roll it thru with the rear wheel off the ground in gear ..
.. the idea is to shorten the top pushrod tube to make room so the locking nut misses when the pushrod is pushing up, but not to shorten the upper tube too much, to the point of making the tube assembly too weak to stay together good ..
.. good luck,
nomad
My motor guy has spacers lazer cut that o in between the head and the rocker boxes, you will need two gaskets for this set up ..What it does is moves the angles in for the pushrods. I've had to switch the pushrods out for strokers as my cyls are.200 longer for the stroke, be fore I had done this work the front solid pushrod conversion broke off on aride. It was under real hard throttle when I heard a ticking ...looked down and the pushrod tube was wiggling around...I got stopped and no real damage had occured.
Dave