zero decking

[4barrel]

I need some advice. Everyone tells me to zero deck my block when I have it prepped. Will this affect the way my intake fits? My buddy tells me he thinks it will.

Is zero decking expensive at the machine shop?

Thanks fellers!

[HeadDoctor]

Thats just engine building 101
The closer the piston is the head the better off you are, so long as you stay within the RPM constraints. At 5K and below you can get by with .017 clearance 5K to 7K you need .021, 7K to 7500 you need .030 beyond that with steel rods you need .039.

Ideally the piston shoud just touch the head at max RPM.

Denny@JDS INduction Products

[mustangII460]

If the deck is square, it don't need it.

[HeadDoctor]

How many blocks have you ever seen that were square from the factory - even some of the after market blocks need to be "Square-Decked"

As far as creating a misalignment that depends on how much is cut off the deck surface, it usually only takes .010 to .020 to straighten it out. Also how much is cut off the heads so its the total of both that affects the manifold.

Zero decking means that you have to assemble one of the pistons in the block and check the (TDC) deck at all 4 corners. The problem lies in - if the piston is down in the hole .040 and you want to run zero deck then you have to mill the deck that far or change something in the rod-piston dimensional configuration.

The .040 on either the deck or the head is going to cause a slight misalignment of the manifold.

Denny@JDS INduction Products.

[4barrel]

Square decking and zero decking, same thing? Or square decking makes the surface consistent, and zero brings it all the way to zero at top dead center?

I'm lookng at building a street/strip 347...have been for about a year LOL. Right now I'm at the stage of getting the block prepped. I should have it ready to take to a machine shop soon. Any advice will be helpful.

[bmxmon]

When I rebuilt my 302 I also wanted to zero deck it, the machine shop advised me not to and spend the money else where.

[Rev]

I think decking the block square is a good idea for any performance engine build. To me it's a $50 well spent. I like the deck height to be such that the piston deck is close to even with the block deck at TDC. My machine shop guru says that if the block decking and head milling added together are not more than .050", then the intake will still fit well enogh to seal.

Rev