does anyone know anything about the -280 heads? i ran into a ludicrously sweet deal on a 396, includes all long block parts fresh out of the machine shop except the heads, which are stock pulls. i figure if they're decent heads i should go for the motor and see how it runs smile.gif

280 heads ? :confused:
They must be -290 castings which are oval, closed chamber and could be either 13/16" or 5/8" spark plugs...depending upon the date of mfgr. Usually around a 101cc chamber.

If they are 290s use them they are as good as you can get for a 396.

On one head it has the following numbers.
1). 3964280
2). GM9T
3). A30 70

On the other head it says:
1). 3964280
2). GM9T
3). A12 70

Any thoughts?

It's kind of a funny situation i'm in. I've always wanted a 396 in my nova, but I just finished a 400 small block with a solid lifter cam, lol. Probably 425-450hp. Anyone interested? I have a complete build sheet and an entire excel spreadsheet of every penny spent on it.

Clean around that "8" really good and make sure it's not a "9". The semi-closed chamber "290" is the only one that has a casting number that's very close to your casting number at all. Otherwise, post some characteristics - closed, open, semi-closed, etc. and maybe someone can help identify them further.

Gotta be a "9" instead of the "8".
Closed chamber oval port heads manufactured Jan. 12th & 30th, 1970.