104* or 108* ??

Given the tall gear and low compression it WILL be beneficial to advance the cam...I guarantee it!
Look at the rpm range of that engine with that gear in a driver....

How much difference are you thinking?,I certainly respect you and your expertise but we are not talking a huge difference in cam timing,especially with the cubic inch.I ran the exact cam in a 360 with a similar build,when I degreed the cam I could not get four degrees advanced with the timing set so I settled on a 102cl with six degrees advanced,I ran it that way and then went to two degrees advanced with a 106cl.The car lost 5 psi cranking compression at the 106 centerline vs the 102 but ran a tenth quicker in identical conditions,for me that was a pretty small change over all.