[Bison256]

My wife recently bought me the giant afterlife ecto 1 set. After putting it together I keep thinking I could follow part of the plans to make a 59 Cadillac Eldorado convertible. Particularly the front and rear halves. After all lego's designers did most of hard work. I can leave out the gunner seat and roof and replace the back door of the combination car with a standard trunk. The question is how much do I shorten the wheel base by. I'll do this in a computer program then order the parts later if I feel like spending money. Any other lego folks here have advice?