84-85 3.8 difference in 86-87 long blocks

[Alaskabuick]

I picked up a 85 long block the other day, new rebuild. Could not pass it up, cheap.

Other than not having the turbo oil return hole in the front of the block, what is the difference between these and the 86-87 blocks?

Dennis

 

[Jerryl]

In a quick, "top of the head" summary;

Turbo Drain tube location
14 or 20 bolt block/pan
Deck height (HG's)
Pushrod lenghth
Casting material
Lifter valley finish

 

[Jerryl]

Repeated post (resulting from operator error) deleted.

 

[Ormand]

Gn TType Block Guide Look here, and you can see the differences. The casting material is the same, but there are other differences, as noted.

 

[87GNSteve]

different head bolts or (studs if you choose)
Different cam and cam bearings because:
85 & earlier front cam bearing journal (in block) is not grooved; 86-87 is grooved