Are the Series I and Series II L67 bock the same?

[chuck03]

I was going thru some information on my '92 bonneville and realized that the '92 has an L67 block designation like the newer series II block. This my not be new to you, but my question I have is this: Is there a difference between the Series i and Series II L67 block. I read that in '96 the Series II was bolted to the 4T60-E. so evidentlly the bolt patterns are the same for those. I guess the ultimate question is this: Is it possible to install series II heads, etc. on a series I L67 block? If so that would greatly increase my ability to tune the car. Thanks in advance for the input.

Chuck
P.S. I found my information here.
http://williamwren.com/timeline.html
:huh2: ???

[Quick6]

No, they are not the same

[DrJay]

Ahhh you found Bills webpage. Welp quick6 is right, they're not the same. There are a number of changes to the engine as a whole between the Series I and Series II. Valve sequence, deck height, and rod length come to mind. The reason the transmission bolts up is the same reason many others will too, its a B-O-P (Buick Oldsmobile Pontiac) bolt pattern. You can attach a number of transmissions to it.

Oh by the way, the owner of that webpage is also an admin at a helpful site:
www.BonnevilleClub.com . Check it out.

[MadMax350]

its a B-O-P (Buick Oldsmobile Pontiac) bolt pattern. You can attach a number of transmissions to it.

Just a slight correction, the 3800 Series I or II does NOT have a BOP bellhousing bolt pattern. It has the more common GM 60degV6/4cyl/FWD bellhousing. The old RWD 3.8 was the only Buick V6 to have the BOP bell.