Cadillac Owners Forum banner

Fast 92 intake rebuild

3172 Views 20 Replies 3 Participants Last post by  Billfrombyron
Hi guys, the Fast install manual isn't particularly helpful, and I cannot seem to locate any videos or other guides/diy on how to replace the inner seal. My problem is that I've figured out that the bolts and nuts which go around the perimeter are missing from mine, there are 6 ea - 3 up front and 3 aft. I am also missing the valley cover bolts, so I ordered the full fast hardware kit, which has these missing pieces.

I have ordered a fast rope gasket, but cannot find any good info on how to install it. Anyone have some pics? All else fails I'll figure it out and take a very nice diy video for my channel and update here so someone can hopefully be aided in the future.

Does anyone know the torque for the fasteners on the front and rear? Not the manifold torque.

The problem with it sealing began with the shop removing the button head screws and replacing them with standard bolts, and just got worse from there. I don't understand why they chose to do this, and I'm still pretty pissed about it, but I also take it as an opportunity for growth and learning as I will be making a diy video of the install process to aid those in this situation going forward.

Now the rear half of the seal is destroyed and the lower to head seals are destroyed.

I've cleaned it all up, and the porting work was done by someone very skilled, it's a thing of beauty and I really want to get it back on the car asap.

There is not much difference between the LS2 and fast 92 stock performance wise, but after heads and cam I have really noticed a difference since switching back to my LS2 stock manifold.
Wire Drawing Branch Plant Sketch
Tire Automotive tire Bumper Auto part Automotive exterior
Auto part
Auto part Engine Vehicle Car Automotive engine part

Also FYI for people swapping back to stock LS2 manifold with LS6 length injectors, you need a 1/2" spacer. I already had the FAST kit, so I had to find long enough hardware. The steam vent bolts are long enough to the mm to secure the taller injectors and rails to the manifold.

Any pointers from people who have done it are appreciated!

See less See more
1 - 6 of 21 Posts
I've never had mine apart. I coulda/woulda/shoulda sent it off to be ported while my car was down for over a year, but I wasn't planning ahead at all and by the time I thought to do that I thought I would have the engine back together in just a couple weeks. Then it ended up being another few months :rolleyes: , so I easily had enough time to do it. Ah well...

Anyway, I'm no help on the info you're trying to find, but look forward to your DIY video.
I'm not sure what I'm seeing. I think the circular marks are what I'm supposed to see, but I don't know what those are.

Edit: Are those marks in the bottom of the intake manifold due to the hex head bolts on the valley cover? I honestly don't know what bolts I've got in the valley cover; I just had everything apart a few months ago, but I don't remember. I may have pictures at home that will help jog my memory. (I got my FAST setup used, so it's possible I didn't get valley cover bolts. But I kind of vaguely recall that I do have Torx bolts for the valley cover? I'll see if I have any pics after work later today.)
Found a pic on my FTP site, I do have the Torx bolts in the valley cover. Phew! :)
OK, I didn't have time to watch the video. Tried to scan for discussion of the intake gaskets, but didn't find it. So... What problem did you have with the Felpro gaskets?
Just realized the reason I didn't find the gasket info is because I was scanning through the 2nd, longer video. If I had watched the first couple minutes of the first video, I would've seen it. Oops.

Anyway, when I had my intake off recently I used the ACDelco 12533587, which I seem to recall looked like the brighter green ones in your pics. I also seem to recall that the gaskets that came out looked like the Felpro ones. Based on your second pic, it looks like the Felpro ones would work, they're just a different style.

Have you talked to FAST to tell them their gasket/rope replacement part is too short? That's pretty crazy that the manufacturer's own part isn't right!
Well, that sucks. I'll admit to having never re-checked mine on the couple of occasions I've installed it. Based on what you're seeing, I suppose I should!
1 - 6 of 21 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.