I just replaced a 1970 250 block with 1977 block. I used all the internal parts from the 70 and now have oil leaking out of the distributor. Its coming up the shaft and out of the cap. Is something different about the blocks or did the machine shop leave out a oil plug?? I have a HEI with the coil in the cap, the newer engine has HEI with external coil, could they be different? Looking at the old block, I can't see any reason for this to happen. I need help !! Joe