I have a B18C1 bored out to 81.25 with RS Machine ITR pistons. I shaved the block and the head. I had to use the adjustable cam gears to get the timing right, since the engine was shorter. i had to move about 1 to 1.5 click on the cam gears.

I was thinking about upgrading the camshafts and i was worried that the valves will hit the piston if i get performance camshafts, since now the valves are closer to pistons. Is that the case? If i were to do this, of course i will upgrade the valve springs. Is it necessary to change the valves? could i get by with out changing them?

What are the difference between stock retainer to aftermarket ones. do i have to get same brands to seat the spring to retainer correctly?

Thank you.