R33 RB26 Cam question

[Neski]

Hey guys,

Im looking at getting the 270* procams with 10.8mm cam lift in the next few weeks. My question is, is this too much cam lift? will it make the valve hit the piston?
I have attached my piston spec sheet, as well as the OEM cam specs. My rods are Eagle H-Beam 4.783 length (stock). I don't believe my head has been decked, neither the block. I bought the engine in the car already and it was pretty well stock with basic bolt ons

I am aware that i will have to get all the supporting springs, retainers, etc with these cams; but will I have to shave the lip of the head to make room for the high lift? I have read that 10mm is the limit until the head has to be cut to make room for the lobes.

Finally, are these cams the right choice for my setup? I have a GT35 with a .82AR. Will they still keep me pretty responsive and be beneficial for my turbo? I am trying to learn how to read compressor maps but keep getting upset and decide to give up haha. Right now with my OEM head i start seeing boost at 2.5-2.7k RPM which is nice.

If i missed anything, let me know and ill get you the info asap.

Thanks for the help

[nismo-152]

A cam with that lift should need valve recessed piston. And yeah the head will need a trim for the lobe to get by..

[leung23c]

I just went through the exact same thing and the answer I get from my guy is...

Yes you definitely need to shave off the bucket area to clear the high lift cams with a milling machine.

And the builder need to use putty to check piston valve clearance to be absolutely sure. Otherwise it is gambling.