Deck Height Even Or Below

[DIRT DODGE]

What do you guys recomend? Small block 360 ross domed pistons with w2 open chamber heads.Shoud I leave the deck height where it is at 10 below ,or mill the block to zero deck.I'll be running it on methonal on dirt. looking to get 12 to 13 to 1 compression.or should I mill the heads to get my results.

[6 packin]

Give us some more specs on the dome cc size and stuff, what head gasket your running and so on.....I can give you a estimate of compression, are you running aluminum or iron head? Whats the cumbustion chambered size in cc's? You mabe better off with a flat top closed chamber design for better quench effect. It really important on how the dome is made. There is no question a flattop enigne will make more power given the same compression, maybe even with a little less. Cometics make a great head gasket that is bore specific that can be had in .020 compressed thickness. That could be as much as a 3/4 point diff compared to say a felpro blue at .040 thickness. Check out Cuda Don in the ultimate phone book for more info on them.

[sanborn]

You are really looking at two issues; piston to cylinder head clearance and compression ratio.

First, piston to cylinder head clearance. You need .035" minimum clearance. This takes into account the head gasket thickness(FelPro is about .040", Cometic has several thicknesses available). With a flat top piston, you could use zero deck without problems. Domed pistons must be checked very closely since they protrude above the deck. The way we checked with domed pistons was to rotate the engine over without a head gasket. If it rotated without interference then you are probably OK.

Second, compression ratio. W2s usually have no more than 63ccs, and can be much less. You need to find out what the chamber ccs are. Then you must measure the valve relief, usually 5-8cc. The .040" head gasket is about 8cc, if the piston is .010" in the hole that is another 2cc. With those specs and a flat top piston, compression would be about 10 to 1. With a .125" FLAT dome, your compression would be about 12.5 to 1. Those numbers are off the top of my bald head without benefit of a calculator----so check them.

Combustion chamber 63cc
Head Gasket 8cc
Valve Relief 5cc
Compression height 2cc
total 78cc
360"/8 cylinders = 45" x 16.3cc/"=733cc
733cc of bore + 78cc of chamber = 811cc /78cc=10.3 to 1. You would need to reduce the chamber cc about 15cc to get it to 12.5 to l. You can do that with either a dome or reducing your chamber size.