My friend has my old 355 that was built by e&r racing. It is supposed to have vortec heads on it( motor was stamped in 09/1996 by e&r) but the manifold bolt pattern is angled on the ends with vertical bolts in the center . Ive also read post from guys who say this is the vortec bolt pattern. I currently have a set of 906 vortec heads that only have bolts on each end and none in the center. What is going on? Are there two different manifold bolt patterns on vortec heads? thanks for any info

That sounds like the 87-95 bolt pattern (non-Vortec).

you got a set of normal heads .. they have bolts on each end and in the middle ..

vortec heads only have 8 bolts .. two in each corner ..

the intake on some tpi units used these vortec heads that have 12 bolts and the center bolts were at a different angle I just ran into this on my car the eight corner bolts are like a old style intake. the others are at a different angle.