Depends on the whole setup and what the goals are. An all-out max effort race motor needs a number of things not needed on a lesser buildup. You can go all the way from a stock rebuild to the max effort scenario and different operations will make the most sense for each level.

Rich

 

Dont want all out race.
This is a weekend and nice weather fun toy only. Im looking to make around 400RWHP and not use any power adders.

I want durability and reliability and will give up a few HP for it.

I will be boring .030" over and installing forged pistons, new rods and refresh the crank. I also have new LE2 heads with LE 1.5 cam and 1.6 rockers.

 

If the deck and heads are flat and straight, you don't have to do anything.

Rich

 

Heads with that much mileage on them need to be surfaced, the deck will be brinelled.

 

LE2 heads are fresh machined and ported from LE including being milled .010".

 

If you do this you will want to figure out what the deck height is...

To find that, have the shop or you put the piston and rod in the cylinder and bring it up to TDC and then measure how far down the piston is in the bore from the deck surface.

For example the stock setup is:

9.025" Deck Height
5.700" Rod
1.55" Compression Height Piston (distance from the center of the pin to the top of the piston)
1/2 the stroke = 1.74"

So

9.025"-5.700"-1.55"-1.74"=.035" in the hole.

What you are shooting for is to have the distance from the bottom of the cylinder head to the top of the piston @ TDC be .035"-.045", so you have to take how far the piston is in the hole and add the gasket thickness to it. This is called quench distance.

Now normally a shop will deck the block to 9.000" so if you do that math from above on a 355 build up it will end up at .010" in the hole. You can then run the Mr Gasket .026" gasket or the impala .029" gasket to get .036"-.039" quench distance.

Bret

 

Damn, I always thought they were ~.025 in the hole??

 

Depends on the pistons he bought.

 

I will be going Mahle .030 over flat forged.