Working on my 53 3100. I put a rear end from a 57 truck under it with 1.75" wide perches and made a plate for under the original springs and bolted the original shock mounts under the plate. Ordered new shocks from napa and they are extended all the way out when i installed them. weight of truck is on the tires and it's the stock height. what do i do, make longer shock mounts so they have more travel.