No doubt this has been covered somewhere before but due to my search being specific I didn't find what I was looking for so now I'm posting this up. My question is - are 4G63 SOHC and DOHC oil pumps cross compatible? I know there are a number of differences between the 6 bolt and 7 bolt engines but this is a bit like starter motors on 4G54 engines - it can be confusing as each application seems to require a specific part. I'm pretty sure my oil pump is chaff and there are a number of vendors selling different oil pumps online. I've seen NOS, aftermarket, SOHC, DOHC and oil pumps to suit fork lift trucks using the 4G63. The engine in question is the 6 bolt SOHC 4G63 build date 1985. This thing is essentially the heart of an engine and I want to make sure my money goes into getting the right oil pump. Which type has the best flow? Am I going to run into high/low oil pressure issues depending on what I bolt up? Is there a 'Holy Grail' of oil pumps that members here are using and recommend?