Fair enough, I can play by the rules.

This wasn't initially intended as a question, rather to open a discussion/solve someone else'* problem, but anyway:

Is the crankshaft and balancer different between LN3 and L27 on US spec. engines?

On the Australian (where I am from) versions of the LN3 (two piece rope rear main seal, coil pack, for ID), the balancer is a slip fit. On the L27(one piece rear main seal, individual coils) it was made an interference fit. Which, then, is used on the US Series 1 L67 models?

Series 1 L67 HBs are installed with a key to lock it into place. So interference would be your answer.

This may be hard to answer w/o looking at them directly.

If I remember right.. the LN3 does not require a puller to swap and the L27 does. I think they are different and have seen differences from year to year on the same engine designations. Therefore it is very possible they are different.

What goal are you looking to accomplish?

Even the 91-95 L67'* use three different balancers.

Right..and my point exactly..

Follow up:

From GMPD, but please note that I found obvious errors where the naturally aspirated and supercharged HB'* were mixed up for some years in the listing.

90 LN3
88959268
24501201

91 LN3
88959268
24501201

91 L67
88960259
24501752

92 L27
88959268
24501201

92 L67
88960259
24501752

93 L27
24503065

93 L67
88960265
24507414

94 L27
24503065

94 L67
88960265
24507414

95 L67
88960264
24504739


Conclusions:

1. The 90/91 LN3 uses the same HB as the 92 L27 in BONNEVILLES. This may not be true in other applications.

2. The 91/92 L67 use the same HB.

3. The 93/94 L27 use the same HB, but different than the LN3 and 92 L27.

4. The 93/94 L67 use the same balancer, but different than the 91/92 L67 or 95 L67.

5. The 95 L67 is a split year by some manufacturers. You'll need a VIN number to determine which one you need.

Don't forget that the 3x and 18x rings may LOOK right, but are sometims offset from year to year. The CPS shouldn't care, but the PCM sure as hell will.

Guys, thanks for the replies. Interesting.

The motive for asking was that I have been half heartedly looking into a S1 L67 M62 swap on to what I believe to be an L27 in my (Australian) Holden Commodore (RWD, 4L60) and I found F14CRAZY'* posts on his swap on which the balancer failed and was suggesting a possible reason.

While I would be grateful for any advice on the swap from this forum, I understand that it is not directly Bonneville related. At the moment, I don't yet know enough to ask too many sensible questions, so I am rather reluctant to waste people'* time here.

If you don't know, it'* not a dumb question. If someone gives an answer that doesn't really know... that is dumb.