[Alan Warman]

I am having problems with my 307 Olds. The problems are #1 keep loosing ring seal. Number 2 the block is flexing and killing bearings. After the Baton Rough race,I noticed the oil pressure was starting to run at a lower pressure at idle. So I cut the filter apart and found bearing material. So out comes the motor and here is what I found. The center three main bearing bad, and the center three cam bearing spun. The main and cam bearing at each end of the block were good except were trash went though them. Rod bearings good except for trash. The 307 block has what they call windowed mains on the center three mains. The block was hard blocked and has about 75 passes on it. My question is can I use a 350 block and sleeve it down to a 307. Also I run solid motor mounts, they bolt to the center of the block. Could they be trying to pull it apart. Thanks for any info