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I am thinking of putting 1.6 roller rockers on my '95 LT1. Is this a "DIRECT" boilt-on? Will I have to change valve springs? Will I have enough valve to piston clearance? :chevy
My suggestion would be to go with the Comp Cams Pro Magnum Roller Rockers. they are the strongest, leghtest over the valve weight, and overall best. You will have to trim the inside of your valvecovers to clear the RR's though. This is very easy with any kind of dremel or grinder. Should take you all of 15 minutes or less.
If you have high miles, it might be a good idea to change your valve springs, but not necessary. You will have no P to V problems with the stock shortblock and camshaft.
We sell these in our Corvette Forum Mall as a stand alone or a complete package which includes 7/16" studs(which are a direct replacement for the stock studs) chromolly pushrods, and guideplates. You will need everything in the kit to successfully change from stock.
Let me know if I can help.
This is a direct bolt on, but as always, it will take some time to bolt in.
I'm running the Pro Magnum setup in my car; it works well, but some slight valvecover modification was necessary.
I'd change the springs. I got away with it on a car before, but I think it's worth it to at least get some LT4 springs and install them. You're pushing it with the 6.67% extra lift and extra rpm on the stocker springs.
I've also run the Crane Gold self aligning rockers (similar to the stock LT4 rockers) and they worked fine, however the Pro Magnums will be a much stronger setup if you plan to do other mods in the future.
For an extra $15, you might also look into a LT4 knock sensor so your computer won't pull out some extra knock retard due to the added noise of the rockers.
Somewhat agree with John, although the 1.6's will make a difference alone. The object is to allow the engine to "breathe" - more O2 in, more exhaust gases out. 1.6's simply allow more o2/fuel in & more exhaust gases out of the cylinder after combustion. With this in mind & to John's point, mods like a larger TB, ram/cold air intake & free-flowing cat back exhaust will give you decent synergy in your setup.
I felt a nice SOTP gain from my rockers which I bought from Chris @ Speed Demon ... a good guy to do business with! :cool:
I agree the rockers are only a small return on investment as far as HP is concerned. The advantage is they are relatively easy to install and have very few drawbacks.
Probably the reason the larger throttle bodies are so popular.
.....If you have high miles, it might be a good idea to change your valve springs, but not necessary. You will have no P to V problems with the stock shortblock and camshaft.
Chris,
There's not any clearence trouble with 1.6 RR, but have you measured the max lift on LT1 springs? I have a set of later springs (97 replacement crate LT1 engine) and the springs are crushed with a max lift of 0.500". The max lift on a stock LT1 cam with 1.6 rockers is ~0.490", I don't think it's wise to use the stock springs no matter how many miles they have.