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Author Topic:   vortec plugs, gaskets
posted August 22, 2004 10:13 AM
We are running the "Autolite AR 472" with Vortec heads. Gap them at .040 unless you run an MSD box, then gap to .045.

posted August 23, 2004 10:33 AM
I think the gasket is #1255 felpro you are right its the thick one. I cant remember the # exactly but I believe the last two digits are 55. use some sealer on the top part of the runners both on the intake and head. Its a close fit but they really do work better than untouched older style heads.

You should run long slot rockers on the vortechs. We use the crane ones. Also pin the studs and don't run more than 510 lift. In a street stock we run a 508 lift Clevite cam that seems to work the best.

Are you planning on having the spring pockets upgraded as well?

If you are getting these new, look at PACE performance. They sell them ready to run with z28 springs and drilled and tapped for old style intake. Throw your rockers on and poly locks and your good to go.

posted August 23, 2004 04:08 PM
That number for the felpro intake gasket is not even listed in my book,i do see a 1245 that is .120(stock is.060)that can be trimmed to fit the ports.

posted August 25, 2004 09:09 PM
Just curious. Why run a thicker intake gasket?

posted August 26, 2004 11:17 AM
I ran the stock plastic for a half season and luckly I did not have trouble. Then I posted the same question on the Sallee Chev web site and got this reply: Fel-Pro 1255, install with Gask-a-Cinch on the intake-manifold side of the gasket(per instructions), torque down overnight, lift intake manifold w/gaskets attached off of motor, trim to fit manifold face, as long as the overall opening is smaller than the intake runner of the head.

If you plan to take the manifold off often, you can spray the OUTSIDES of the Intake Manifold gaskets with a light but thorough dowsing of Silicon Spray. Wipe up other areas where you don't need that conveniece.
I like to use a brand-new Xacto blade in a handle to do this right - for a V8, I might change blades 2-3 times to stay steady on the cut... worth it to spend $1.50 in blades for something you want done right.

Also, with these gaskets, I like to put a thin layer of sensor-safe RTV around the water passages - seems to help prevent weeping or minor leaks.
.....I called the part store and did not have a problem getting them, followed the instructions above and have no problems. I run the new intake pattern so you might have to cut new holes in gasket for old pattern, can't remember if it was cut for both ?? you do know a regular intake wont seal on the vortec because the port is taller.

posted August 26, 2004 05:14 PM
I thought it was 1255 for the gasket. Just was going from memeory though.

Also watch your lift on your cam and....RUN THE LONG SLOT ROCKERS! Unless you like asking for trouble as a practice.

If you find some cheap cores, have the spring pockets worked over to accept the z-28 springs and install the long slot rockers you'll be good. While they are there have em clearanced for the lift you want to use.

I did get a little squirter leak from the front bolt holes when I first installed mine but a some teflon tape and RV silcon solved that problem.

posted September 18, 2004 09:49 PM
The reason for the thicker gaskets is to raise the intake up high enough to seal the top of the ports. The Vortecs have a higher port and with the thin gaskets there is a gap at the top. Even with the thicker gaskets, there is no room for error. The tops of the intake port and the head port leave next to zero gasket surface to seat on. A little silicone at the top can ensure an adquate seal. BTW, since the intake gaskets need to be mail ordered where I live, I've had to remove the intake a few times while reusing the gaskets. Still no leakage problems

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