Thread: How much to mill on intake

Tweet

Hello,

I'm building a tall deck chevy 10.2 deck. I believe the heads have been cut but not sure how much. Brand new tall deck intake mounting on but the bolt holes don't line up. I can get one side bolted no problem. The intake sits perfectly on the heads, just sits up to high. I was using a .060 gasket to mount, when I removed the .060 gasket I was almost able to get the blots in on both sides. Does that mean I need to remove a minimum of .060 off the intake? I do not want to machine the heads on the intake side. There is plenty of clearance on the block China wall. The intake is a dart tall deck. Do the dart tall deck intakes need milling from the get go?

Thank you in advance.
J

Yes I have tried the punch to center the intake. The only way to get the bolts in would be to drill out the holes. I do believe .030 off the intake would work, but than would i need to take additional off for gasket?

Yes when I tried with a .060 thick gasket the bolts wouldn't go in. When I tried without the gasket I was able to bolt up one side and almost the other side. I figure I have to take off at the least .060 for the gasket and maybe another .060 to center the bolts. That just seems like a lot to me.

As I posted in my first post there's no gaps it fits perfectly. I can't take pictures as I already dropped the intake off at the shop to be milled. The intake is to high it needs to be milled. I'm taking .080 off, .060 for the gasket and .020 extra to line the bolt holes up better.

I wouldn't do 0.080" myself. Gaskets compress a little, and if you go too far... I would take 0.025"-0.030" to start, and test fit. And, one big thing you need to keep in mind, if you cut too much off, the valley rails will hit. Use silicone and not the rubber end rails too.

Also, the amount you remove is not a linear measurement, but rather an amount relative to the cosign of the angle.

GM BBC 109cc closed chamber head: Head 0.0065" per 1cc
Remove 0.007" from intake side of head (or manifold) per each 0.010" removed from head/block
Remove 0.0193" from end rails on block for each 0.010" removed from head/block

GM BBC 119 Open chamber head: Head 0.005" per 1cc
Remove 0.007" from intake side of head (or manifold) per each 0.010" removed from head/block
Remove 0.0193" from end rails on block for each 0.010" removed from head/block

Originally Posted by 69Bee

I wouldn't do 0.080" myself. Gaskets compress a little, and if you go too far... I would take 0.025"-0.030" to start, and test fit. And, one big thing you need to keep in mind, if you cut too much off, the valley rails will hit. Use silicone and not the rubber end rails too.

Too late just picked up the intake. I did read that dart intakes require milling out of the box on oem heads.

Originally Posted by 69Bee

Also, the amount you remove is not a linear measurement, but rather an amount relative to the cosign of the angle.

GM BBC 109cc closed chamber head: Head 0.0065" per 1cc
Remove 0.007" from intake side of head (or manifold) per each 0.010" removed from head/block
Remove 0.0193" from end rails on block for each 0.010" removed from head/block

GM BBC 119 Open chamber head: Head 0.005" per 1cc
Remove 0.007" from intake side of head (or manifold) per each 0.010" removed from head/block
Remove 0.0193" from end rails on block for each 0.010" removed from head/block

Great info! Thanks, I wish I would have cc'd the heads before I installed them.

.080 was $$ it was rite on, centered the bolt holes. That was the border line max though.

Good to hear...

Thank you to all that replied