06 dyna, stock heads. Zippers redshift 557 cams, thundermax autotune, thunderheader,
Zippers says cams need 9.0-9.8 comp, I have a spare set of HD cylinders that im sending out to be reworked!!!! I want to build a 95" as cheap as possible,
I'd like to stay with SE parts, as i get very very good deals through a buddy, Can someone tell me which SE pistons to buy? I cant do any headwork right now... Im not savy on squish, static, or cyl pressures!! Just looking for solid advice on how to make the cams i allready have installed happy with 95" jugs...

 

SE cast flat tops (PN 22851-99A) with a .040" head gasket will set your static at 9.8; corrected and CCR a bit on the soft side but is should run good. You could use a .030" head gasket and push static up to 10:1 but while the heads are off, you might want to have compression releases installed. The releases are not absolutely necessary but nice to have if/when you need them and they don't cost that much.

 

Thanks, I checked around alittle and those seem to fit the bill nicely, Collecting parts now to send in with the cylinders for fitment...

 

Djl, what actual comp would that put me at? I know there is alot of variables, and with flat top pistons i shouldnt have any issues with valves to piston clearence right?

 

PHA-Q, I screwed up on my initial calcs. I was working on something else and neglected to change the chamber volume in my calculator to the stock chamber volume, so we have to start over. Zipper's says the cams like 9.0-9.8 static compression, so that is what you should try to achieve. I think you could go higher but let's stick with Zippers recommendation for talking purposes.

The only way to precisely estimate compression is with accurate data, i.e., chamber volume and deck height being the two variables that require measurement. With 95" bore/stroke, SE cast flat top pistons, a .030" head gasket and assuming 85cc chambers and .003" deck height your static CR is 9.3, corrected CR 8.5 and CCR 172. Static is in the Zipper's recommended range and you can run there with no issues. However, going to the upper end of the Zipper's recommended range will make more power; problem is, you can't get there unless you reduce chamber volume. Two ways to do that, use the SE 10.25 cast domed piston or deck the heads about .040". The domed piston pushes your compression too high so you would have to shave the piston dome; decking the heads and staying with the flat top pistons is the easy way to go.

I know you said you didn't plan on any headwork at this time but, if you can afford another $100-$125, having the heads ccd and decked to 80cc chambers puts you at 9.8 static; the upper end of the Zipper's recommended compression range.

I use my own calculator but have attached copies of the calculations at 85cc and 80cc from the BigBoyz calculator; the link is also attached so you can use it yourself and check out the effect of making changes.

Apoligies for the error and misinformation previously posted. I am very careful when posting information like that as it is important to post accurate information but I screwed up on that one and I apologize. If you need some assistance figuring out how best to proceed with your upgrade, PM me.

http://www.bigboyzheadporting.com/TwinCamComp.htm

 

No worries at all, you gave me more info than i have been able to get on my own, Thank you... Sounds like i need to have my heads worked over to take advantage of my cams

 

You have the '06 heads which flow pretty well; almost as good as an early set with a "stree" port job. A quality triple angle valve job and decking about .035" or .040" and some new guide seals will not cost that much; no need for a full port job for this upgrade. Get the compression right and a good tune and you will be impressed with those cams. Don't hesitate to PM me if you have more questions; don't mind helping out.

 

Enhancing the cylinder head flow chateristics, along with the correct compression, will make a world of difference.
Scott