Several versions of the origin of the nickname and which chassis number should be associated  have come to be heard over the years. 

Chris Willes probably knows more than anyone at this time. He has talked to a lot of people in the past several months while researching a book project.

I always thought it was the name given to a car put together from a repaired wrecked tub during the summer of 1989 by Terry Nichols. Sadly Terry is no longer with us. I thought the name for that car was Elvis meaning that it never died. We carried that car to Del Mar for the final race of '89 (image--from L to R: chassis 8801 [w/Terry Nichols leaning on car's RH rear wing], Primary #84, Primary #83, Spare). It was a runner but not  considered as a car we would race. It was made from an old Lola tub that had been on the roof of the building for several years. The repair of that tub, and it being assembled into a complete car, is undisputed fact. We took a picture of it along with the 3 active race cars at Del Mar early in the race week. The question being, is it Elvis? I think so but the majority say not so – to the point that without Terry to confirm I am confused too. 

I do believe Terry gave a car the name Elvis. He and John Morton were Elvis fans.

I think most involved think it was the 8801 car. The name could have come from John Morton who sang some Elvis songs at the team Christmas party accompanied by a very good band made up of some of the guys on the team.