Are vortec heads vortec heads or is there a certain casting number I need to look for?

any SB vortex heads should work but you also have to get the vortex TPI manifold..

Vortecs are Vortecs. Scoggin-****ey makes a TPI baseplate and many companies make regular mainfolds.

Ive been told that you can modify the stock base inorder to get it to bolt onto the heads. I was gonna do this but decided on aluminum l98 heads. Btw have you checked out WWW.KSFBA.ORG

Curtis

the reference to "vortec" heads are the cylinder heads used
for GM trucks 1996-2000 V-8. in 1999 GM also uses a style
called "vortec" on the new body style trucks. this in fact is
the new LS1 head and at this time is not able to be bolted
to GEN1 blocks. be careful about the term vortec in someones
sales line. ive seen LT1 heads being descibed as "vortec".
and aluminium vortec heads are called fastburn. not aluminium
LT1 heads, too. LT! heads can also be used, but some precision
machine work has to be preformed.
airdeano