505 stroker fresh off the dyno - Power seems low? Thoughs?

604B1duster said
I hope your feeling better and doing ok.
I have icon 4.382 bore pistons with 16.4 dish that look the same as what’s in your motor, 440 source just advertises as 17cc but it’s an Icon 16.4cc piston. Besides, they use the same photo for all the dish pistons on the 440source site.
That spinning assembly is 10.705. With the block cleaned up, I would think it’s gotta be within.010-.025 deck clearance.
How tall could the block be ? ..What’s the tallest factory block you guys have seen ?
With that cam, calculator says roughly
10.4-10.7 compression and 8.0 - 8.3 dynamic, depending on deck.
The static and dynamic compression ratio calculator

If the deck height is tighter, .00-.010
Static and dynamic go up close to 11-1
and 8.5. Maybe it’s detonating and why power was dropping off over 30* Timing ????
Mix some race fuel in and run it again,
bump up the timing

I appreciate your concern.

The machine shop just cleaned up the deck surface. If it was detonating, I have to think the Dyno guys would have noticed. I'm mostly deaf, but I don't notice anything. We just finally fabricated the exhaust on, so I'll get to drive it on the road tomorrow. It seems to run really well though.

Honestly, I'm more worried about figuring out why it made peak power with the ignition timing is so low. Temps are dropping fast up here in MN. Looks like I'll have it drivable just in time to put it away. I still plan on pulling the timing cover and verifying valve timing before race season. Sure wish I had a ceiling in my shop so I could heat it.

Any other tips on what could cause such low timing would be greatly appreciated. Will give me a place to start looking in the spring.