Engine Leakdown and Compression results

1985 302 HO with original heads, Weiand intake, Holley 600 CFM carb, headers and 3” exhaust.

A little confused by my leakdown and compression test results. A couple of the cylinders with lower compression have hood leakdown results. These both were dry, cold tests. I know results are better hot, but that’s not an option today.
1. 12%, 150
2. 10%, 145
3. 10%, 150
4. 8%, 125
5. 11%, 120
6. 12%, 145
7. 10%, 145
8. 15%, 130

All leakage during the leakdown test was coming from oil filler hole indicating rings.

Wondering what others make of these results?

I’ll be swapping the heads out this winter for a set of built GT40 heads I have.

7991LXnSHO said:

So how much of a breeze or hiss is that 10-15% leak down test making? Is it a whisper or a mad Siamese cat hiss?
My initial opinion-
Run it hard as is and do a rebuild when you cannot stand the smoke or plug fouling. I’m not sure I’d put heads on it until I needed to tear it apart.

Click to expand...

It’s hard to say. This hiss is audible, but not overly loud.