Looks like I can't attach DXF file here. I'll try to PM it.
Here's the PDF and a pic showing orientation and which 3 bolts you're looking at. I truncated the one boss where the head gasket is a little proud of the head.
Thanks to Brian, was able to make a head mounting plate and he let me mock up on his motor. I was able to verify the pattern. My son, Mason will make me thicker tubes to weld the bracket to the compressor as the tubes we have are too thin to weld to the bracket, I believe.
Eating the elephant one small bite at a time.
I walked around this chassis 200 times today, getting caster and toe done. It was crazy this took so long every twist had an affect on another and had to learn how things moved and caster affects toe. I am very close but tires still just barely rub on full compression to the lip of the body.
After taking apart my transaxle 3 mo ago I cleaned, soda blasted and cleaned it again. Well the humidity and time grayed it out again. Found a guy in League City TX Thad did vapor honing, said he would do it for me while we met old friends for lunch. $80 the pieces look super, and his son just bought an old ERA 40 which has not been on the road in over 20 years, and will be delivered this Friday.
Bobby had a beautiful ERA 427 Cobra, so I am sure the will do a great job rehabbing the ERA 40
Now would be a good time to give it a coat of Steel-It gray polyurethane. It gives you a hard, glossy finish, I had never heard of it until I visited Allen Grant shop to see his Lola GT Mk6. He recommended it to me and I have been very pleased with it. There are other vendors who sell it for a bit less.
Hmmm got home, all knock offs fit the front spindles that we had with us at the shop. Will not thread on the rears???? I am too tired and need a shower and will have a look in the morning.
I fitted the knockoffs onto the front spindles while they were on the lathe and hot from threading. This morning they were snug, put them in the oven, warmed them, threaded like butter. Used fine valve lapping compound and WD 40 and fitted all to spindle like butter cold.
Now to the issue with the rear.. the spindles are .006” to .008” larger than the front, hence why they will not thread on. The thread are Whitworth 55 degree 8 tpi which are the same as original cars.
I'm assuming this was threaded in a lathe. Is it even possible to get it re-indexed to cut deeper?
Your answer may be cut a undersized male thread in a tube, and slit it so it can compress, then lap the spinners to size with that.
Or maybe do the opposite on the rear hubs so you can make front and back interchangeable. But I bet the alloy of the spinner is easier to lap than the hub.