RagTop
Old Grumpy
I've always used Castrol GTX 10W-30 in my Mustang but the high ambient temperatures up here in Sacramento are causing the oil pressure to drop off as the engine heats up beyond it's normal operating range. I'm considering changing from dino oil to synthetic oil and also going up a level to 10W-40. I've also been warned that the Castrol could be a problem for a flat tappet hydraulic cam because it doesn't have enough zinc. Has anyone else changed over from dino to synth.? Has anyone got any opinions on doing this with a 49K engine?