I was not happy with the weld ring on my headers.
What I did was tig weld up the outside flange to header pipe
and then remove the weld ring by resurfacing the whole flange
that bolts to the head. After resurfacing I cut the flange between
every exhaust port. Also by doing that I was able to gain some
more clearance in the shock tower mustang by resurfacing. By doing
that I got 100% seal around the port. They been on the car for over
10 years without any leaks. I dont know the measurements because
they are on the car and hard to get at. Hope this helps some.

Rory  Thats a great base line to start with.
A deep sump pan also helps in keeping the
oil a bit cooler in temp.

Little Info on my 4-speed and gear vendor. I can push the button whenever I want to and it will shift into the high side of the gear I am in. It also has a launch control on it which I dont really use. The other thing is if you want to sell it some day you can sell it to anybody. Can be Dodge or chevy also. All they have to do is buy the tail housing adapter,everything else is the same. The over drive is great for engine RPM and gas mileage. Hope this helps some. Car is 69 mustang with no tunnel mods. at all.(lucky I guess)

Something to think about. As the pic. showed the flywheel been heated up and with that it could have hard spots in it after grinding it. It could cause clutch chatter. Its like when your rotors are warped and you cut them ,the brake pedal will start to pulsesate after a shot time. That is do to hard spots on the rotors because they got to hot. That does not go away without buying new rotors.

Thanks guys
I will start with the blue bushing and 1 lite silver spring and 1 lite blue spring and see how it runs.

It seems to run good at 15 to 16 initial and 36 total. I guess I could try the black bushing and light springs but I would have to change the initial to about 18, so I would end up with 36 total. With the 18 initial and the light springs I am wondering if that would be to fast of a advance which may cause detonation?

I installed a gear vender behind my big in and big output trans. in a 1969 mustang. I did change the main shaft to 14 inch. and also changed to a wide ratio. Works great without no mods. to the tunnel. I also think if you would have a 17 inch. adapter and then the vender there would be a lot more weight hanging off of the rear trans mount.  That could cause problems with the extra weight and also installing the unit. Tunnel problems.

Hear is more on Gene Cromer. Hope this works. I did see him race the car at Byron Ill. a few years back. Great show.
https://youtu.be/ZE3FbloYtWs