fordracing65 Isky built them back in the late 60- to early 70's. I have talked toEd sr isky on this. He has no ideas about where the patterns are.
As BarryR or Jay B. who both build FE motors they go with just the valve springs to control the whole mass when running and this works.
Jay B is building the old PSE manifolds that come in 2 parts with an upper and lower bases. This manifold would give the lip for a plate.
The problem with FE motors are the heads have no stick out points like GM motors to mount the upper plates too. The tie bars that keep the lifters align with the cam lobe are another problem with clearance for the cap and spring.
If you changed to another lifter that uses either a "T" bar or has an alignment pin built into it with a bore slot in the lifter bushing, this would work.
If the cost to not a problem Building it would be easy and use 35-40 pound springs. This is with hydro lifters only. I think you have a whole bunch of problems with solid lifters and running a rev kit with valve lash and what parts are going to get hammered each cycle. You also might have to look at running a .904 lifter even with lite spring pressure in the 400-600 range.
I was told that beehive springs would break, didn't work well, and wouldn't live with a .600" lift camshaft. In 12 years of running them out side of a 10 pound loss in pressure at max lift, they are doing just fine. There is a little more power made with them. The down side is they float the valve train at bout 5,600 rpms. Have seen this on dyno runs. I have also gotten around this with .015" valve lash and running high
oil pressures. The lifters stay pumped up at high rpm and the valve still close. There is a small dip in power of 40 hp but the motor will pull to 6,200 my max rpms. PAC makes a strong beehive with 420 pound over the crane 377 pound rating. This should get the motor to 6,500 rpms if needed.
I think that if you run a rev kit that controls the lifter on the camshaft lobe, you can run a lighter rated valve spring and still control the whole setup and even pick up a couple of hp and torque numbers. I think the motor might rev a little quicker. Valve seats and valve will not bounce and hammer each other so hard.
Barry R. has done some great work with Engine master challenge with a 50+ year old motor. I am a student of motors over the last 40+ years and broken ,windowed, cracked, twisted just about every motor from the last 50's to today. I have talked to every machinist who will take the time and give their ideas about building motors and their theories. There are a vary in theorys about
oil pressures running what grade, what pressure,
oil coolers and if additives are needed. I have a 16 year old Shelby block that gets abuses at tracks with road racing and autocross. I run high pressures. and here is my reason, what you are reading at the oil pressure gauge IS NOT what the pressure is at the back of the motor going to rods #4 & #8. On the broken motors I have seen rods #4,#7,#8 are the ones that have broken almost everytime. WHY? John Conley did a test and found that with an FE running, the back of the motor got 10-30 psi pressure less than the front, at idle speed. Same applies for flooding heads, cooler the valve springs the better and stronger they work under loads. To each his own with this. I will say that adding an accusump to your car and using it as a preoiler before firing it up and on running in any high "G" event will help save the m otor and stablize the oil pressure readings unless you go dry sump. Good luck with your build. Rick L.