High lift and high revs dictates the need for heavier springs.
The ca18 engines are 25 years old with who knows what thrashing the springs have had.
I dont know that springs and retainers are needed, but I wasnt married back then, so I didnt need to be sensible with budget.
Ive only managed 188kw at 12 pound boost, but forged pistons, turbo, cams are designed for 20-25 pound boost.

Hey Dattodude what sort off hp you punching out?do u need to put different springs to suit different cams?

You get bigger springs because of spring supply issues.
The heavier springs help valve bounce at high revs.

You wont find any camshafts with 15mm lift.
I used JUN springs and retainers in my ca18, and i run 9.25mm lift tomei cams, standard valves.
I'm yet to spend the time/money to get a proper tune. But ive had no problems.

Hi guys got another off my unending questions,ive talked to a few people about the brand Supertech.Their head components and the valves springs say that they can take up to 15mm lift.That should be more than enough to cope with tomie procams which have 8.8 or 10.25 lift.Am I on the mark or not?

Go and have a yarn to an engine builder and build some repore. That you will get to know the bloke and get an idea if you can trust him before starting the engine build and more importantly handing over your hard earned

Hi guys got what might seem a stupid question to most but when u put bigger valves in its only the head off the valve that is bigger and the springs,retainers are still standard size.

My apep pistons with stock valves can handle 270deg / 9.25 mm lift tomei procams.
Datrotor is right. Head design decisions will determine what cams and pistons you will need. Trade prices do exist, and it would be unlikely you'll do it much cheaper on your own. Unless you get lucky both on price and choices in parts.

To be honest mate I'd be telling the builder what you want and let him do and buy everything.from the sound of it you don't exactly know what you need so you may get the wrong parts.best to tell him and let him do it all

Guys when u put lumpier cams in does the length off the valve need to be changed?And also should I be sticking to something like Tomie.