Thread: 81 corvette engine (need opinions)

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All old generation heads had 6 bolt holes for the intake, the new ones have 4. They did away with the two in the middle. Also, the bolt holes are not perpindicular to the head on the Vortecs. Check the casting numbers on those heads, Vortecs had 906 or 062 as the last 3 digits of the casting numbers. On the outside, where the accessory bolt holes are, Vortecs have 3 triangles in a sawtooth pattern. If your heads show none of these characteristics, you do not have Vortecs. My new engine got my truck with highway gears pretty close to the 14's and I know it's got a lot left in it and that was with just the XE256H.


Look closely at this picture and you can see 2 of the 4 vertical bolts for the intake and the sawtooth pattern on the front of the head.