im not sure if this is the right forum but im usually posting over at iroczone but i guess thats not there any more so i hope you guys can help me out.
At one point my 86 IROC had an engine swap done and i therefore know nothing about this motor. IM planning on a head/cam swap but i first wanted to know what heads this thing has on it. So i pulled the valve cover and got the stamping number but it seemed allilte off:

3888338
or its
3886336

It also had GM 7 stamped in the middle of the head. Ive been to every corner of the web looking for this number but i can find it. Does anyone have a code book that can tell me about these heads?

 

Could it be 3986388? or 3986339?

 

IM not at my house so ill look again tommorow. Im pretty sure theres no nines, but the fourth and last 8s did look like sixes to me.