i got a set of heads with the numbers 8973487X on them. pull them off of an 86 Z28 that was carburated. that first digit could be a 3 instead of an 8 also. i've looked but can't seem to find this number in the books. any help will be appreciated

 

It is 3973487X, 1971/72 350 head, 75 cc combustion chamber.

Mortec: http://www.mortec.com/castnum.htm

 

thanks alot Zed'er. now, are these good heads or run-of-the-mill
heads? i may keep them for my next camaro project or sell them on here.

 

Those are factory 2.02/1.6 valve heads, compared to 1.94/1.5. I would assume they are pretty decent heads.

 

Zed'er do you think these heads would flow better than some aluminum heads from a 91 vette? i have an 87 Z28 350 TPI with the 91 heads on it. i have'nt ran the car yet, so i dont know how the aluminum heads are yet.

 

I believe these heads have 161cc intake runners and 60cc on the exhaust. If the Corvette heads are L98 the are 1.94/1.5 valves, with 58cc cumbustion chambers. I don't have any data on whether the smaller chamber heads (aluminum) would be better or not. They probably flow better than the old cast heads. I am sure someone on here will definately have an answer for you though.

 

The 487X heads are one of the better casting of the 70's era "junk smog heads" The corvette L-98 aluminum heads are much better to start with and have more potential in ported modifyed form. (the exhaust port is much better).
In stock form the intake ports flow about the same.

487x come in 1.94-1.50 version and 2.02-1.60 from the factory. The combustion chamber varys in size from 75 to 80cc's .
Of the two heads the corvette L-98 aluminum head is the one to use.
Hot ticket is to home port them and install LT-4 2.00"-1.56" valves.

 

thanks for the info guys, i love this forum. i guess i'll keep the 487X heads for a later project.