No Oil to Rocker arms for at least 4 minutes after cold start. The engine is a 1971, 455 YC block that has 1975 6X number 4 heads with 455 HO exhaust manifolds. Which I believe came on a Pontiac 400 engine so 93.74 cc’s. There is only 1400 miles on engine since it’s rebuild and dyno. Upon me, getting the car and needing to adjust lifter noise, I noticed that I’m not getting any oil pressure up to the rockers on cold start for at least four minutes after the engine has started. Once the engine is warmed up the oil, flows freely and plenty of oil gets to rockers. I checked the oil pump and did a pressure check at the oil filter adapter and was getting 60 -65 psi at cold start up. Did these Big blocks require a 80 psi pump? I pulled the heads off and the cross hatches are still very prevalent in the block. Any ideas on what may be the problem?

No Oil to Rocker arms for at least 4 minutes after cold start. The engine is a 1971, 455 YC block that has 1975 6X number 4 heads with 455 HO exhaust manifolds. Which I believe came on a Pontiac 400 engine so 93.74 cc’s. There is only 1400 miles on engine since it’s rebuild and dyno. Upon me, getting the car and needing to adjust lifter noise, I noticed that I’m not getting any oil pressure up to the rockers on cold start for at least four minutes after the engine has started. Once the engine is warmed up the oil, flows freely and plenty of oil gets to rockers. I checked the oil pump and did a pressure check at the oil filter adapter and was getting 60 -65 psi at cold start up. Did these Big blocks require a 80 psi pump? The engine was quiet as can be on the bottom end, so I’m pretty sure the bottom end was getting oil Any ideas on what may be the problem?