Stupid intake question

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Wildcat1

Wildcat1

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So I hate to even bring this up, but I got another 340duster a couple of months back. It's been rebuilt and has a stock intake on it . I've tried to put a rpm airgap.on it but I can not get it to line up . I hate to think someone decked the heads without decking the intake side .Does any experts on here think maybe a different gasket set would help ,or any other ideas
 
What gaskets are you using now? Is the intake "high" or "low"?
 
You need to use the "composite" gaskets which are thicker so that won't help. In my experience aftermarket intakes always sit "high" so when my Performer RPM didn't line up on my engine (slightly milled Edelbrock LA heads on Magnum block) I just had the intake milled by my local machine shop. If I ever go to put it on another engine and it sits too low (highly doubtful) I'll just get creative with the gaskets. I can't remember how much was milled off the intake but it was just enough to where I could get the intake bolts in (it still sits slightly "high").
 
You need to machine the manifold. Or the heads. It doesn't matter. If you do the heads and move them to a different block they won't be correct just like machining the intake. It's always been my way to do the intake manifold. They are cheaper to replace. Plus you can get different thicknesses of gaskets.
 
Just to keep it simple, did you remove the valve covers first ? And are you trying to use the cork end gaskets that come in most intake gasket kits, cuz they can hold the intake up. If you take the cork gaskets out, do the bolt holes line up? If it does, then use rtv gasketmaker(1/4" bead) on the ends.
 
Once you get the valve cover gaskets & dowels out of the way, you'll be able to start estimating how much the intake needs to be milled at the port surfaces. (Or the just the heads on their port surfaces.) If the bolt holes line up without intake gaskets, you'll need to mill the thickness of the intake gaskets being used. (Maybe .010" less to account for compression.) If the intake still sits high, you'll have to estimate how much more than the gasket thickness needs to be milled. Adding the estimated misalignment of the bolt holes to the gasket thickness milling amount will get you close.

I always cringe when I see "ovaled" intake bolt holes.
 
I milled my 273 heads .010 to true them and milled my LD4B mating surfaces .010 each side. I used high temp silicone on both sides of the intake gaskets and the install and startup is trouble free.
 
Baxter61 said:
Are the dowel pins still in the Block?
Click to expand...
PAY ATTENTION HERE He's talking about the small pins in the top of the block across the "flat" area front and rear where the intake sits. Many aftermarket intakes don't have those holes so you must remove them, or figure a way to drill the intake
 
I always run the cork gaskets on the china rails but I just put them on without the intake gaskets and bolt the manifold up. This sqashes the cork gaskets then I unbolt the manifold and proceed to put the intake gaskets on and bolt it up again. Works for me, no intake or oil leaks and I have done this many times.
 
Do yourself a favour.Leave the stock intake on it, they work great.
Flog the air gap for a tidy profit or spend it on something that will make a difference!
 
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