How much needs to be machined from my intake?

Jim Sullivan

Well Known Member
Supporting Member 10
I had my 348 block decked 0.030" and I was hoping the intake would fit without machining. I can't quite line up the holes, and I could probably file the holes. But, I would like to know how much should be machined off of the manifold to make it fit properly. Unfortunately, my machinist passed away over the winter and I'll have to find someone else to do the machining, if I go that route. I'd like to know ahead of time before going to another machine shop just to check their knowledge.
 

Fathead Racing

Well Known Member
Supporting Member 7
Just guessing here. I'd say half of what the block was decked, that would be around .007 off both sides. Drop the intake on without the gaskets on place and see if the bolt alignment is better, this will give you an idea what you need to remove. Measure the thickness of the intake gasket. Why did the machine shop take so much off the deck? Your pistons will probably be out of the hole too, maybe at zero with luck.
 

Jim Sullivan

Well Known Member
Supporting Member 10
The pistons are still down in the hole about .005". We calculated how much to deck the block after a preliminary mock up. Trying to keep compression up as high as possible with a double notch block. Good idea about trying the intake without a gasket, that's what I'll check first. Thanks.
 

MRHP

 
Supporting Member 1
Intake gaskets are different thicknesses as well. I think Victor are the thickest from memory. May want to get some measurements. I know Edelbrocks are pretty thin. I have a set of Edelbrocks I can measure if needed. May have some Fel Pros to measure as well. Let me know.
 

Don Jacks

Well Seasoned Member
Supporting Member 3
Eddies measurements won't help here.He's running 817 heads.The idea of measuring the gasket thickness is a good idea. With the heads on,place the intake on the engine,without any gaskets. Look at how the bolt holes line up,them check the gap between the manifold and the engine block.
 

Skip FIx

Well Known Member
Nice chart Cecil. Does that chart work for our W motors with a slightly different block angle than most motors?
 

Don Jacks

Well Seasoned Member
Supporting Member 3
The old Chevrolet Power books from GM used to post that chart.The spec's are slightly different on both the 60 degree v6,and the Mark 1V engines,but this will get you very close.
 

Jim Sullivan

Well Known Member
Supporting Member 10
I checked the intake to head and block. There is .072" gap between the intake and heads and there is .090" gap between the intake and the block. The intake is nice and parallel to the heads. I'm not sure what gasket I have but it seems pretty thick. I'll see if I can measure a few different gaskets to see what I can find.
 

dave1961

Well Known Member
Supporting Member 1
Cut the intake side of the heads instead of the intake,otherwise that intake will most likely only fit on that motor combo,also allows you to try a different intake if you want.
 
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