I've read a lot of threads about 'normal' compression on a TC96, but most end up talking about the addition of cams and other assorted add ons. What would a bone stock 96 run? The best info I could come up with was minimum 90 and norrmal 140-160. Sound right?

 

I have factory service manuals for shovel heads, EVOs, Twin cam 88' & 103" engines... I don't have one for a Twin Cam 96" engine...

From what I've read, minimum acceptable compression is 90psi... While 90 psi is acceptable, it will be a rather "tired" engine. I have also read that on a 96" engine, 145 - 165 psi is normal range for a fresh engine. But acceptable compression, on all engines, also includes the caveat that the difference between cylinders is 10% or less...

Obviously the max compression will change with cams and displacement. I believe the most important parts are the over 90psi and within 10% difference between front & rear cylinder...

IMHO.....

Lower than 90 psi or greater than 10% difference on any twin cam would cause me to immediately strip it down to the cases, and do a top end rebuild...

Also any compression test on any Twin Cam that's below 110 psi, I would start planning my top end rebuild.... It would be sooner rather than later...

Just for a comparison/reference:

My 2003 Heritage (95" big bore kit), after adding a new cam plate/tensioners and new A26 cams, had a compression test of F185/R185psi with a leak down of 2% front & rear @ 100 psi.

My 2001 Springer (88" stage I), purchased 4 years ago with 9.8K miles, on my initial inspection, had a compression test of F155/R147 with leak down of 2%F & 5%R @ 100psi.

 

Thanks for that info. I did a cold engine (I know that a warm engine test is better and would yield higher results) compression test on mine, 39,000 miles and got 148 front and 149 rear. Thought it was odd to get more on the rear than front, but one pound difference isn't worth worrying about. Ran a bore scope down it

and both cylinders looked exactly the same.

 

Looks good to me, I believe you are just fine...

And will be for quite awhile with good maintenance habits..

Enjoy....!