I can understand not wanting to pull the heads. Then you need to disconnect the exhaust manifolds, take off the mounting brackets for the alt and power steering, air cond. stuff. It really does look clean inside. It is up to you. If you don't think that you will have the "would have, should have, could have" and you are confident then put it back together. I would still put break in lube on the cam since everything is really dry from sitting. pour some oil on the lifters and let it soak down inside. also try some lube in the pistons (it will smoke for several minutes till it burns off). maybe rebuild the carb and see what happens. Use wisdom and read what others have offered. I am no expert.
Good luck, your doing great.