The first thing I do when assembling a SL6 intake to exhaust manifold, is to bolt the two manifolds together, at the "hot box", with-out the gasket, align them the best I can, then inspect the "mocked-up" assembly.

If you can not get the two manifolds to seat flat & evenly together, figure-out why and correct... before attempting the final assembly and alignment, with the gasket.
If the surface between the two manifolds does not allow for good "full contact"... any gasket you attempt to use, will eventually fail.

Most often cause of trouble... a badly warped exhaust manifold.
I grind and "fiddle" until I get the manifold to manifold mating surface correct, while watching the manifolds to head (port face) surface... trying to keep them even.
After assembly, we grind the port face surface flat and sometimes have to port-out the port opening(s) to adjust for the warpage.
DD

We ended up using the Aussie gasket / RTV-on-metal-gasket combo and it seems to be holding up, so far. Left a thick bead of high-temp silicone on the metal gasket overnight to cure so it would be a little more built-up. Also had to double up on the exhaust pipe gasket. Must be something out of whack on Aaron's exhaust system.

_________________
There's a difference between ignorance and stupidity.
Ignorance is not knowing any better.
Stupidity is knowing, yet doing it anyway.

Yep, I just coated both sides of the gasket with copper RTV and made sure I bolted everything on properly. Let it set-up overnight and then ran the motor for 5 minutes to heat-cycle the RTV sealant, and left it alone for the rest of the 24 hour cure period. Also RTV'd the downpipe exhaust gasket, but don't think it was needed.


So far so good. Quiet exhaust

If it leaks again, I'll use the opportunity to get some head-work done and maybe a new cam. Also install the cloyes double roller timing chain and aluminum valve cover sitting under my bed.

Anything wrong with the heat riser metal gasket and intake gasket that came in my felpro set?

They're too thin, unless you have perfectly flush mating surfaces... Which isn't likely after 30-40 years

If I were to use the metal gaskets, I'd sparingly coat them on both sides with Copper RTV sealant. The gaskets may or may not work as it seems to be a crapshoot.

Probably better to use the thicker Aussie or Remflex gaskets.

What Jester said. Those stamped steel "gaskets" almost never seal. Maybe they worked okeh when everything was brand new, but the odds are against your getting even a half-decent seal, even if you goop it up with RTV. It sucks having to do all the heavy lifting again; worth your while to wait for a Remflex or Aussie gasket.

_________________
一期一会
Too many people who were born on third base actually believe they've hit a triple.

I have the Aussie Gaskets in stock. PM me for price and shipment.
Frank

_________________
Scrapple: Because a mind is a terrible thing to waste.
73 Duster - Race Car
66 Dart Wagon - DD
178" FED
82 D150
All Slant powered

im wondering should i spend the money on a remflex/aussie gasket, or use the felpro gasket, i do have that blue hallomar stuff in my drawr, which i read can be used in the installation article.

If the manifolds are flat the Felpro manifold to cylinder head gasket works fine.

_________________
Joshua

Do you feel lucky? If the manifolds are in very good condition and alignment, the Fel-Pro gasket will probably work to seal the manifold-to-head junction. The odds are very much against the stamped-metal hot box gasket sealing for you, though.

Not a good gamble; this job is a pain in the rear and I try to minimize the number of times I have to do it. So I advise waiting til you have the good gaskets in hand unless it's a real emergency, needed-vehicle-off-the-road situation.

_________________
一期一会
Too many people who were born on third base actually believe they've hit a triple.

The remflex "hotbox" gasket is almost 3/16" thick and compresses to a little under that. It should work fine if you have two mismatched manifolds and the exhaust hotbox is a little short (sometimes happens if using an earlier manifold and a super six intake). If you need one of those I have a few hanging around I'd sell for $5+ postage, since I get the remflex gasket kit, but have no use for the hotbox gasket, they just hang out in my misc. gaskets box.

-D.Idiot