I'm about to take the 4.6L out of my 99 deville. I've purchased head gaskets from the dealer and they suggested 'big-serts'. I bought 10 of them, expecting to have to drill out some stripped threads. The size they gave me were M11x1.5. Some questions...I've been looking for the kit and/or the correct tap for this item with no success. The full kit is $459. Are there any other successful 'time sert' kits available that are easier to get and cheaper? If I were to stay with these bigserts, would the tap size indeed be M11? Is there are thread spec? And what would the correct size drill bit be? Thanks!!!!!

The "Big Sert" is used IF the regular Timesert should fail or you screw up the installation. It gives you a second chance at saving the block. Have you checked Ebay for a used kit?

Did you read both stickys at the top of the Northstar forum regarding head gaskets? They both have a lot of useful info in them. Good luck....

There are threads on this galore. You should read some before you start. Get the factory service manual. Here's my write up,

http://www.cadillacforums.com/forums/northstar-performance-technical-discussion/5052-n-head-gasket-repair-part-i.html

Tateos had a long thread with a lot of tips. You'll have to look for his.

I suggest Norms:

http://cgi.ebay.com/ebaymotors/NORTHSTAR-ENGINE-NS300L-HEAD-BOLT-THREAD-REPAIR-KIT_W0QQcmdZViewItemQQ_trkparmsZ72Q3a1205Q7c39Q3a1 Q7c66Q3a2Q7c65Q3a12Q7c240Q3a1318QQ_trksidZp3286Q2e c0Q2em14QQhashZitem160295580418QQitemZ160295580418

I suggest Norms:

http://cgi.ebay.com/ebaymotors/NORTHSTAR-ENGINE-NS300L-HEAD-BOLT-THREAD-REPAIR-KIT_W0QQcmdZViewItemQQ_trkparmsZ72Q3a1205Q7c39Q3a1 Q7c66Q3a2Q7c65Q3a12Q7c240Q3a1318QQ_trksidZp3286Q2e c0Q2em14QQhashZitem160295580418QQitemZ160295580418

I'll second that, those are what I used when I did mine this past summer.