For my 2004 Discovery, 4.6 L engine, I intend using Cometic head gaskets, because they are vastly superior to any other make head gasket, though more expensive. For the Land Rover, Cometic head gaskets comer in 94.2 mm and in 96.08 mm bore. ANYONE KNOW WHY THEY COME IN THESE TWO SIZES FOR LR? Best I can determine, Rave calls for the 94 mm, while original LR composite gaskets were 96 mm. I don't have mine off yet, so can't tell if they are 94 or 96, but I suspect they are 96, being original. SO WHICH PAIR SHOULD I USE, 94 OR 96 MM, AND WHY ONE INSTEAD OF THE OTHER BORE SIZE? THANKS FOR THE HELP.

 

Honestly, your money would be better spent on an ARP stud kit + composite gaskets. The HG failing is just the nature of these trucks, and no insanely expensive head gasket can address that. It'll still fail just as soon. I had a buddy try Cometic gaskets on his 01 4.6 Range and they still failed 4 years later.

Now if you were building a heavily boosted engine, then those head gaskets would be appropriate, though the engine would still blow just from non-head gasket issues

Also, HELLO FELLOW OREGONIAN!

 

Bore is 94mm, 96mm is overbore, and you want these for what practical reason? I wouldn't even bother with studs, more prone to pulling threads. Both are high dollar items on a no tech motor, like gold plating a walnut. I'd go with Felpro 26532PT and a good set of bolts from Rovahfarm.

The problem with the Rover block/head is the two middle cylinders are siamese, no cooling through the block. Head warp is the result and it's gonna happen even if you parked an Abrams on top of it.

If I was gonna spend nearly a $100 bucks on head gaskets I'd buy the engine they belong on.

 

Turner engineering uses elring gaskets, and they rebuild and sell thousands of these blocks. I use elring.

Definuteky 94 mm. 96mm is not even an overbore, that's like drilling into the coolant jacket territory

and from what I've read.. skip the studs. Using tty stretch bolts is important and has less risk of cracking your block. In my opinion.

 

The only reason a stud would pull threads out is if the threads are already weakend (looking at you Northstar V8 and Toyota 2AZ!), otherwise there is a large benefit to studs. The thread on the head bolts for the RV8 are a very course thread that makes it near impossible to get the torquing 100% even. With the studs, the nuts go on a much finer thread, making it much easier to apply completely even torque. There is a reason that once studs are put in these engines the head gaskets last MUCH longer than just going the typical bolt-route.

 

studs are better hands down. Make sure you get the actual arp kit for the 4.0/4.6 not the cheap buick V8 studs i both both and measured them the buick are shorter.

 

not to mention torque to yield bolts start adding stress before full depth because they have to be stretched.