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I've found a set of Vortec heads for my 77 L48. Any other considerations or
changes, other than intake, I will be encountering when changing? I plan on using the stock exhaust manifolds.
Any input will be appreciated. I know some of you guys have made this modification.
Thanks,
mox 77
The factory springs are not made for high performance cams. You may want to upgrade the springs before you install them. I had no problems installing mine. You should also consider the GM reusable intake manifold gaskets. I have read that they work great and are good for multiple reassemblies. I plan to get them next time I remove the intake.
Mox, I'm running this right now. I didn't do the build up myself, so I can't be much use to you on the assembly.
But you're right, the intake has to be different. And the stock heads require a milder cam, no more than .456 lift. Another thing I learned, was that the stock water temp sender will not work with the new heads. But go with a non EGR intake (Edelbrock) and use your stock water outlet to park the sender. The sender will screw right into the top, with just a little bit of thread sealer.
Good luck with it. I'm still in break in, but from what I know, these heads are real nice. If you have any other questions, give a shout. :cheers:
Everything noted in the previous replies is accurate, from my experience. The valve guides need to be cut down to lower the valve seals for a cam with lift over .460. Also, the intake manifold bolts are installed vertically rather than on an angle like the original heads and manifold. So if you are planning on using any brackets that are bolted to the intake manifold, you will need to improvise. There are only four bolts on each side of the manifold, rather than six, the middle two are eliminated. If your car has A/C, you might have a bracket to support the compressor which originally mounted to one of the bolts which are now missing. More improvising. Other than that, the Vortecs bolt in like original equipment. Don't forget the self aligning rocker arms.