Blocking Off Exhaust Crossover

[440sixpack]

On Mopars you can get a block off intake pan.  is there any reason on an FE I can't make metal block off plates for the crossover ?


My main concern would be will the heat destroy the fiber gasket around it ?   if so is there another way.

[Drew Pojedinec]

I cut a piece of sheet metal, tap it in, and smear some epoxy over it to hold it in place.

Lotta different ways to skin this cat

[cjshaker]

Lots of guys just use a butter knife, cut and trimmed to fit the area. I've done this also. Works good because they're about the perfect size, and stainless.

[440sixpack]

I was thinking more of a metal piece that fits the hole in the intake gasket.  if you just plug the hole in the head wouldn't there be a chance of it coming lose and falling down behind a valve ?

[jayb]

I've done exactly what you suggest countless times, usually 18 gauge or thicker sheet metal.  Just size it to fit the gasket opening, and use some silicone to hold it in place when you install the intake.  Works great.

[Barry_R]

Yep x3
silicone and a chunk of butter knife, dulled off razor blade, or a piece of hobby shop brass

[BigBlueIron]

Recently on a Streetmaster I cut a chunk of scrap aluminum to kind of fit/fill the hole then welded it in. Dressed with a grinder. looks like it was made that way.

The reason I choose to do this is it just makes more sense to me, I didn't want to fiddle with a little piece of metal just the right size and have one more thing that might slip or move on manifold installation. I actually started to fit a piece and thought why don't I just weld the damn thing closed! I know that will be fool proof. Which is important because I'm the fool.

[Falcon67]

I use pieces of .015 stainless shim stock.  Allways block crossover down here on any "hot rod" motor, even with a cast iron intake. 

[440sixpack]

 Thanks I fab something up.  I just didn't want one of those " what were you thinking " moments to come back on me.

[chris401]

Has anyone here ever compared temperature before and after a plate of metal? Although exhaust is not swishing directly through the cross over heat does transfer through the metal plate. I have been threatening my self with testing for years but haven't yet.

[cjshaker]

Never did a temperature test, but if you look at factory cast iron manifolds, the paint is always burned off at the exhaust crossover. Then there's the reason for the valley pan in the first place, to keep oil from coking and baking onto the bottom side of the intake due to the crossover. You don't get any of that when the crossover is blocked. There's no doubt that it helps.

[440sixpack]

If you block the crossover do you still use the vally pan then ?   I guess it wouldn't hurt anything.

[cjshaker]

Guys differ in opinions, but I always try to use the pan. It does help keep oil from being thrown on the bottom side of the intake, which has to help keep the temp down, at least somewhat. Some intakes just don't work well with the pan though, so it depends on that also.

[thatdarncat]

Has anyone here ever compared temperature before and after a plate of metal? Although exhaust is not swishing directly through the cross over heat does transfer through the metal plate. I have been threatening my self with testing for years but haven't yet.

I haven't done a temp test either, but along with the keeping the heat from running through the manifold, exhaust gases are very corrosive, that's why so many of the factory aluminum manifolds rotted out through the exhaust crossover. Blocking the cross over will help keep your new or collectable aluminum intake from deteriorating.

[440sixpack]

I just have a cast S code intake but with an electric choke I see no advantage to heat in the intake.