Engine guys, have a question on compression

[wage92]

Okay so ive been trying to find a good rotating assembly for my 406 sbc, and i found one that i think i can live with but its not exactly to my specs. it will give me 10.35:1 static compression and i want to use this cam ( http://www.lunatipower.com/CamSpecCard.aspx?partNumber=60104 ) with it but every dynamic compression calculator gives me different compressions so im not sure if i will be able to run it on 93 octane...anyone shed any light on this?

Aluminum heads also.

 

[earnett]

From what I've read you should be good on 93 octane up to 10.5 to 1 dynamic compression. Also the cam should have a min compression ratio rating probably 9 to 9.5 to 1. I put your 406ci and 10.35 static and cam spec through a calculator and came up with 9.4 dynamic compression. That should be good for 93 octane but my best advise would be to call lunati and talk to their tech support.

 

[4X4HIGH]

Do you know what your piston deck height is? Without know that you cannot tell exactly what your compression ratio will be. Also there are usually a couple options for head gaskets that will play a small roll in the CR also.

 

[76zimmer]

In a heavy vehicle, that should be about the max you would want (9.5 dynamic compression) with Aluminum heads...otherwise what the others have already stated!

 

[wage92]

Do you know what your piston deck height is? Without know that you cannot tell exactly what your compression ratio will be. Also there are usually a couple options for head gaskets that will play a small roll in the CR also.

pistons would be in the hole .025" and i would use a .020" gasket.



Im thinking that i will order all the parts seperately that i want and get them balanced by a machine shop...will be more costly, but it will put me at about 9.8 static which i am more comfortable with

 

[greensideup78]

Well if it helps any, Im running a 406 in my camaro with 10.1:1 compression ratio with cast iron heads. So far its been ok on 93 octane but I haven't run it at the track yet, just on the road. From what I was told you are ok up to 10:1 on pump gas and cast heads. Any higher you want aluminum heads and higher octane fuel. This came from an engine builder friend of mine.

 

[wage92]

im sure it would be fine, i just dont know if i wanna be that close to the limit...