360 magnum 10:1 pistons

[MOPARCODY]

Accidentally dropped a nut down the carb so while I have the heads off I'm going to have them ported and polished and I'm also considering putting some good higher compression Pistons in it. Motor only has about 25k original miles and still has the cross hatch in the cylinder so I don't plan on boring it out. The motor is basically a 360 380hp crate motor clone with eddy heads and crate motor cam.

Any suggestions on Pistons

 

[krazykuda]

Read through this to find out what your compression is.

Then measure the deck height of the piston dome that you have and figure out where you need to go to get where you want...

http://www.forabodiesonly.com/mopar/showthread.php?t=278215

 

[MOPARCODY]

thanks for the link all good info.

now hopefully someone who has built a mild magnum engine has some insight

 

[magnummopar]

Have you checked your CR with stock pistons? If your Edelbrocks are 58cc then you should have close to that now. How far are stock ones down in hole? What gasket do you use? The crate engine had flat top w reliefs but 63cc chambers to get to 9.5. Need more info.

 

[MOPARCODY]

Head gasket thickness is .038 I believe. Pistons are .040 in the hole

 

[sireland67]

KB 107's should yield around 11.1 with the eddy heads.

 

[magnummopar]

If you do the calc's on CR with the info: 4"bore, 11cc dish(factory 5.9),.040" in hole, .038" gask and 58cc chambers you will probably be pretty close to 9.75:1. A 10:1 piston will put you in 11:1 CR which is probably too high.

 

[MOPARCODY]

If you do the calc's on CR with the info: 4"bore, 11cc dish(factory 5.9),.040" in hole, .038" gask and 58cc chambers you will probably be pretty close to 9.75:1. A 10:1 piston will put you in 11:1 CR which is probably too high.

11:1 would be ok. its just a bracket car so i could get away with mixing the race gas or pulling timing and running pump gas if i wanted to cruise on the street. or i could just put the extra money into the heads...