i have a set of 993 heads

[blazin_blazer]

i have a set of 993 heads in my shop, they hecho en mexico...i have been told the 993 was a sorry head, b/c of the mexican casting they are 1.94/1.5 valves....

i ran across another set of 993 heads, they don't have the mexican casting, the shapes on the end of the heads are different(1 is a simple triangle, the other has a split level rectangle) but they are off the same motor, both have the 993 casting # but they have 2.02/1.6 valves, on one of the heads it has "conv 4" in a rainbow shape around 1 of the head bolt holes...they have alot of casting numbers & letters that i've never seen on sbc heads before...are these some rare or good casting head?

 

[4X4HIGH]

AFAIK all "993" castings came on target master engines made in Mexico. The casting is a good thick casting head and they came factory with 1.94"/1.5" valve sizing so someone installed the larger valves into the one set of heads you have.

 

[big dan]

I once had a set of 993 heads that came off of one of those crate engines and had "hecho en Mexico" on them. I also had a set of 993 heads that had just regular casting marks.

I have a book with casting numbers in it and it has two listings for the 993s, one for the Mexico heads and one for the regular heads but the specs were the same 1.94/1.5 valves and I think 75 or 76 cc chambers and a heavy casting.

 

[80' 427]

I have never cced them but the mexican heads look like smaller ports.

 

[blazin_blazer]

i'm wondering what ''conv 4'' means on the 1 head, and why the casting shape on the end of the heads are different, but both have the 993 casting #'s