In this case "ot" means off-Toyota and is directed to the technical experts here. Anyhow, I just put a rebuilt 390 in my old Ford pickup. It has a big cam (lots of duration, lots of lift), stock heads with hardened seals, new pistons with reconditioned rods, Edelbrock RPM Performer intake and a big carb. I did the 15 minute break-in properly and it sounded great. After only a 20 miles or so I noted a clacking sound that was intermittent. I pulled the plugs from the offending bank and noted all four cylinders had good compression. I pulled the valve cover and noted that #3 intack and exhause were not moving as much as the others. I put it back on, restarted and it sounded and ran great. Later that day, another five miles or so, the clacking resumed with a vengence. I stopped, took off the valve cover and discovered a badly bent pushrod in #4. Some of the cam lobes appear to be trashed and at least one of the lifters is beat up so badly that there is a HOLE IN THE BOTTOM OF IT! My machinist claims that the cam and/or the lifters were defective but I suspect the cam was degreed wrong. What do you think? Thanks. jor
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18 years ago