Yes.so i have a 90' block. should i upgrade the oil pump or no?
Yes.Yes.
Isn't there a spline difference in the non-vtec and vtec oil pumps?Yes.
But I dont think it matters. I believe that when you try to buy an oil pump for your car, you automatically get the newer model one. They did away with the old pump design and substituted the part numbers. You need to make sure this is correct when you buy one, but Im fairly certain it is.
That could be it. I just remember one of the gears that the timing belt turned had a different amount of teeth between the vtec and non vtec. It's been a while since I had the LSV, so I'm a bit rusty on all the ins and outs...Paden, are you referring to the gear for the timing belt? I believe they are the same tooth count. The differences between the VTEC and non-VTEC timing belt teeth counts are the water pump. And the water pumps are designed differently as well for cavitation purposes.
I read an article on T-I that the writer documented the differences in oil pumps and I believe the part numbers (what you can purchase now).
I think the only difference is a simple washer that increases oil pressure. The pumps should be same whether they are for a B18C1/C5 or B18B1/A1.