I am trying to figure the compression on a 2007 TC96" with stock jugs & pistons, Screamin Eagle 72cc Heads, and a .030 cometic gasket. I think my math is bad. I am coming up with a number around 9.75:1..........Stock Compression on a '07 is 9:2:1

I know this doesn't affect the numbers, but I will be running Woods TW-7H cams, Zippers ThunderMax, and V&H ProPipe.

 

Do you know the deck height? The shorter (.009") rods on the 07's cause the pisons to sit "down in the hole" and usually creates deck height <0, thus reducing CR. Did you also factor in the valve reliefs in the piston tops?

 

rods arnt shorter in 96 piston pins are located higher for the 3/8 longer stroke. pistons are not >in the hole<

 

EDIT:
reply retracted... not worth arguing over.

 

I think you will be alot higher than 9.7!

but you will need to blueprint some parts so you know for sure.

 

With my caculations come up with 10.15:1with an adjusted compression of 9.5:1 with the cams.

 

Thepistons will be in the hole.

They shouldn't be in the hole...but they WILL be in the hole.

I am like Phil...I am not going to bother arguing the point with you.....but it'sa very well known fact regarding the 96 inch rods....they're shorter than HD admits or planned. 10 minutes of searching here or the other forum will give you all the info you need.

 

Well, I bit the bullet and picked up a Zipper's ThunderMax from my shop yesterday. I will have it installed today.

 

95% of the builds we do we shorten the cylinders slightly 95", 96", or other wise.