The link I posted above is now working (my main web server went down, so I had to move the website to my other web server).
All 1958-1962 235 and 261 blocks were set up to use either hydraulic or mechanical lifters. Note that the hydraulic and mechanical lifters for these years have to be used in these blocks (earlier lifers will not allow oil to get to the head/rocker-arm).
Tim
