Shudder While Engaging 1st Gear

[Anthony]

If your flywheel had heat damage, your pressure plate did as well. Are you replacing it?

While your friend it under his care for 2 years, did he take the car out for rides?

[CriticalMass]

Thanks patrick. It's an odd memory to have given it was almost 3 decades ago and I was a little kid at the time, but I specifically remember my dad doing it when he built the car. He was meticulous and much more qualified than I am when it comes to these kinds of things, so I trust that I could do no better than make things worse.

Anthony: I'm replacing the pressure plate as well. It was driven periodically (but sparingly) while in the care of the third party...really just to keep things lubed and exercised, but I trust that it was not abused. I think it was just coincidence that the problem developed in their care.

[DanEC]

Take a look at the alignment dowels in the back of the block. If they are an adjustable type then it was probably dialed in before. It still would be a good idea to check it to be sure but at least that would indicate it has been done previously.