Thread: Question regarding diesel heads

I am working on an '85 6.2L (J) engine that had recently blown a head gasket. The heads that I pulled off have a casting number 14077162, but it is cracked pretty bad near the valve seat. I came across another set of heads that have a casting number 14028901 that I could use. The only difference between the two are the threads for the injectors 28901 (Course) 77162 (Fine). What other differences are there between these two heads? How will this affect the performance? Any information will be helpfull.

Thanks

The coarse thread heads were the first ones produced for the 6.2s. They have a tendency to crack across their valve seats. They, like other 6.2 heads, can be sleeved to mitigate the cracks.

6.5 heads will fit a 6.2. Later heads were machined (and valve size redused) to help prevent cracking. Later heads use a different injector angle to reduce smoke.

Use Fel-Pro head gaskets and, if possible, ARP head studs when you reassemble the engine for the best results.

Originally Posted by engr2007

I am working on an '85 6.2L (J) engine that had recently blown a head gasket. The heads that I pulled off have a casting number 14077162, but it is cracked pretty bad near the valve seat. I came across another set of heads that have a casting number 14028901 that I could use. The only difference between the two are the threads for the injectors 28901 (Course) 77162 (Fine). What other differences are there between these two heads? How will this affect the performance? Any information will be helpfull.

Thanks

The 14077182 heads have smaller valves and therefore more metal between them - and therefore less apt to crack. Intakes are 1 3/4" and exhaust 1 1/2". The 14028901 heads has larger valves with the intakes 1 15/16" and exhausts 1 5/8". If you look closely,there is very little space between them.
Also, the heads have different precombustion chambers. The 14077182 probably have two dot chambers for HD use - i.e. "J" code. The 14028091 heads usually have LD chambers marked with one dot. Also, with the 1982 14028091 heads there was a coolant leak problem that GM fixed with a repair kit. It was caused by an extra coolant port that had to be blocked with a plug. I can't remember for sure if the port was in both the heads and block.