We'll find out this weekend when I try the aluminum gaskets on my '97.

Yeah, then we need someone with some '95 heads laying around to take a look at 'em to see if they have the locating holes.

Hey Ben, don't forget your camera when you go back to finish your car; you can get some pics of your heads.

Let'* say you had a head without locating holes. What would be the problem with just cutting off the plastic locating pins and using the gaskets anyway? That is, as long as everything else matches up. You could do it very carefully, so as not to damage or disturb the surrounding materials.

I was wondering that myself. I wish I'd been there when my dealership was working on mine, I'd have liked to have seen everything firsthand with my own eyes.

Here is another piece to the puzzle. I went to FelPro’* parent site, federalmogul.com - poked around and found their online catalog: I checked every gasket specified for the 3800 Series II LIM from 1995 to 2003, and found only 4 part numbers:

MS95809 1st design w rubber end seals without locating pins exc supercharged 95-97
MS95977 1st design w rubber end seals without locating pins supercharged 96-97

MS95809-1 2nd design w rubber-plastic end seals w locating pins exc superch 97-03
MS95977-1 2nd design w rubber-plastic end seals w locating pins supercharged 97-03

2 for the L36 and 2 for the L67. All four are listed for 1997 models. That must be the year that locating pins and holes were added. But not for the gaskets – for the end seals. I think the gaskets always had locating pins, and all SII heads have holes for them. It is just like the description says: “rubber-plastic end seals with locating pins.” Don’t know why I didn’t read it that way before. I think GM changed the block in midyear 1997. This could explain why bugsi and bignews1 were spec’d different gaskets from GM for their '97'*.

If you look at the end seals that jr’s3800 got for his 1995 and compare them to the end seals bignews1 got for his ’97, you will see the difference. If this is correct, the question is: Will the end seals interchange? Or, more specifically, can the new end seals w pins be made to work on the earlier engines? I hope so. Maybe Ben can find an old design end seal somewhere to compare when he installs his new aluminum gaskets this weekend.

Are those new (red and black) end seals a little shorter?

Jr's3800 LIM gaskets for his '95. The end seals should be the GM equivalent to FelPro’* MS95809. Notice they are rubber with no locating pins. (At least, not that I can see in the pic.)



bignews1 LIM gaskets for his '97. The end seals should be the GM equivalent to FelPro’* MS95809-1. They are plastic-rubber with locating pins. (You can see the pins in the black plastic on the underside of the seal on the left side of the image.)


Now all we need is some pics of the early and late end rails to compare.

Any help out there?

i dont have pictures but as bill said, I used the 2nd FelPro design with the locating pins, worked great.

Bill, the LIM gaskets that came off my car were the GM 2nd design, and for some reason I didn't think the end seals had locating pins. Maybe I'm crazy though. I'll be able to compare them when I go home this Friday, since I still have used ones laying around. IIRC, the set that came off the car looked just like the picture of the gaskets Jr. used.

We are getting closer by the minute. ..corvettecrazy, your '96 should be the older block with no holes on the end rails for those pins in the seals. If they worked fine anyway, that implies the new aluminum set will work on '95-03, and that is just the news we wanted to hear.

Lets try to get some more corroboration and pix. I'll be interested to see what you find out this weekend, Ben. Let us know.

Well, the information was right here all the time. It was right where it should have been - linked in Jr's3800 UIM Techinfo post! Thanks to Boosty and Highlander for the '98 image and thanks to Jr's3800 for the '95 image (both of which I ripped off without asking!)

Notice that the heads both have locating holes for the LIM gaskets. The only big difference I can see is the locating holes on the end rails. And I think the end rail length must be the same. It appears that you can use the newer end seal with the locating pins on the old rail, like corvettecrazy reports. The pins would just end up hanging in the air. With a little RTV to hold it in place, I don't know why it wouldn't work as well as the old style. Now, the older no-pin end seal might have to be altered to work on a car with pin holes. But it'* hard to figure why you would want to do that when you can install the new aluminum gaskets?!


Jr's3800 1995 L36


Highlander'* 1998 L36


Unless I am missing something (wouldn't be the first time), this is good news.

I agree that this is good news. Are you sure you are not a detective, lol? Good sleuthing skills. It surely looks like we now have all the pieces of the puzzle.