scott937

i have a 95' z28 and im doin a cam swap with a cc503. My question is 1: is there a big difference between 1.52 rockers and 1.6, if so what? and 2: Do any 1.6 rockers work with this cam or no, any answers would be great. Thanks

96lt1m6

iTrader: (31)

1.6 rocker ratio is preferred on all small blocks words from
Mr.Vizzard
John Lingenfelter
to name a few!
a little extra lift never hurts(within reason)

Green3spd

iTrader: (7)

More lift, More power!

flyin97formula

I was wondering the same thing...
Do you have to worry about piston to valve clearance?

StealthFormula

iTrader: (35)

You wont have piston to valve clearance issues with 1.6's and the cc503.

Here is the lift benefit of 1.6's over 1.52's with that cam:

Lift with stock 1.5's = .503/.510
Lift with 1.52's = .510/.517
Lift with 1.6's = .537/.544


1.52's would be a complete waste of time money IMO as you can see. The 1.6RR's will yeild you more hp. 99% of guys running that cam including myself just recently, use it with 1.6RR's.

scott937

alright cool, thanks again

01Z28M6

Pardon my borrowing this thread but the topic is correct.

While buying gaskets and bolts I was told that my GM LT4 hot cam kit with 1.6 RRs will result in .525 lift for both intake and exhaust valves. I'm told this will require machining of valve guides and spring pockets on my LT1 heads. Is this correct?

cnorton

iTrader: (1)

Valve-to-piston clearance has a great deal more to do with duration and the profile of the cam lobe than it does with lift. It's difficult to estimate the possibility of interference even when you have numbers for duration @ .050 lift. Putting in any camshaft that's more aggressive than a base factory grind without checking the actual clearance is asking for problems. The more modifications that are made (things like, deck height, replacement valves, gasket thickness, lobe separation angle, intake centerline, rocker ratio, etc.) the greater the need for checking becomes. There's too much risk of a potentially catastrophic problem to justify cutting corners.

That's just my opinion.

01Z28M6

I understand. I'm wondering if anyone has had that clearance issue with stock heads, gaskets etc. with the GM LT4 hot cam kit. The rest of the engine is oem.

r_trigg

iTrader: (1)

Another aspect is the spring retainer/valve guide clearance. I remember when my buddy first put 1.6 rockers on his bone stock 95...he bent 4 push rods because the retainer was hitting the valve guide. The added lift was compressing the spring just enough extra to cause this problem.

Just a thought.

01Z28M6

Could your friend have possible mis-adjusted the preload? Yours is the only post other than someone explaining that they had bent, oddly enough, four valves after installing the cam, rockers and lifters which had drained down. The preload had been set in this condition. This apparently caused a huge pump up after the engine had started.

I don't know much about this so I'm just trying to get to the bottom of it all.

94GreenMachine

iTrader: (16)

yes, more info on this please.

Kmaroman

iTrader: (1)

how do you tell if your car has 1:5 pr 1:6 rocker's it came with roller rocker's when i got the car they have polylocks on ehm to

Captainofiron

iTrader: (1)

I have 1.65 NSA steel rockers on my car and theyre awesome.