i pulled the covers to adjust my rockers so i jotted down my casting numbers. they are 978487. then i search 2 different sources and i cant find this number. it was the only number i could see besides a 14 with GM under it. any ideas? i only looked at the passenger side though. i forgot to look while i had the cover off the other side.

 

You must not have looked very hard,

3973487....71-72...350..........used on 71-72 350 LT1, 75cc chamber
3973487X...71-72...350..........75cc chamber

 

Now before someone gets too excited about having early LT1 heads, please let me explain.

9,999 out of 10,000 pairs (maybe more) of the 487 and 487x heads you may run across are going to have come off of a plain-jane 4-barrel 350 from the early '70s that was originally in a Caprice, Impala, Chevelle, Monte Carlo, Camaro, various trucks, etc.

Mortec tends to get people's hopes up a little too much, especially on this one.

The bright spot (well, not ALL that bright) is the 487 and 487x heads are among the better smogger heads you could get. However, there are much better choices nowadays.
jms

 

the motor was actually pulled out of a 71 vette. i checked the head on the driver side and i could read the whole number, thanks

 

Ive got those heads on my car, the motor is out of a 71 blazer. The ports are much better looking than on my 624's in the basement. The motor in the t/a is a decent performer, but could beneift from better heads and more compression, but then again what motor wouldn't?