Building a 557 ci wondering the best head

[junkman 77]

I am building a 557 bbc and I am wondering what would be the best head for this engine looking at 15-1 compression conventional head engine with loads of nitrous I think the 370 oval would be choice but wood like others feed back please

[corcon]

I'm not sure about the best heads to use but with loads of nos I think 15:1 is way to much compression.I have 14.2:1 and I'm told I have to much for lots of spray.

[junkman 77]

We have a simular set up with 15.5 :1 with three stages at 350+ on each stage and it seems to be the most we can get.

[corcon]

I have dart 360's with 4.50 stroke and 4.56 bore .I was spraying 250 hp to it.Iwill go to 400 shot and I was thinking about lowering the compression a bit.You don't think there is a problem?Thanks

[junkman 77]

as long as your parts are devoted and you give your engine proper time to cool there should not be a problem and what I mean is if you blow your tires off on the line do not restage take your car back to its pit and let it have propper cool down period I watch so many people burn pistons for lack of patients its pathetic. It is also good to have some type of data log to see what your engine turned when you broke your tires loose to ensure no over reving might have happend. Also alot of time will be spent on the head chamber and top of my pistons to insure there are no hot spots that can lead to falier even with all this in mind we still can over do it when weather conditions are at its finest. Going to a lower compression ratio may help create more power with nitrous being that there is less contour of your piston. My belief is that if you can run high compression with as flat a piston as possible and still keep a great head chamber design you will make more power. But I am just an amature when it comes to engine building when there are people like Sonny and Fulton out there and companies such as Par that lead the industrie in Nitrous engines better to get their opinions than mine. There is alot more to nitrous engines these days that help with attrition and a science to tunning them what might work for me may not work for you and with so many varibles that come in to play we are left to do are own r and d. So I hope this could help.

[junkman 77]

Par sells engines capable of 4.0s in an automatic promod now that is making a name for your self

[corcon]

Thanks.I will try lowering the compression to 13:1 and try that.I have data aquisition,it's great.Thanks