Need advice 360 timing chain cam/crank slightly off

340challconv said
Purchased a 360 from Mabco to put into my A66 340 Challenger short term while I pull the 340 for a rebuild.
I bought a hp version with flat top pistons and installed hp cam sited as a 272 cam
Cam specs; 272-272 duration 454 lift 110 lobe separation 52 degrees overlap, 216 216 duration @ .50
Power range 1500-5200 Considered the largest "stock" cam for this engine
In going over the engine for parts install; the timing marks are slightly off.
I call the manufacturer and he stated to leave the chain as is.

Pistons are flat top 30 over, no valve notches, piston to deck measurement is not a stock (deep in the hole) 360 with the higher compression pistons it measures out at about .087 below deck with number 1 piston at TDC.

I am no expert, and I have installed cams years back always aligning timing marks; is there a reason for the manufacturer to alter the timing in this manner with this hp cam and flat top piston?
Pic of timing chain sprockets and Number 1 piston at TDC
Any thoughts appreciated.

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Thoughts........Don’t waste you’re time calling Mabbco with any more questions. You already are likely flagged as “we might have issues with this guy” by asking about the timing set and questioning things. Either do the correct thing as a few here have told you to do or......do what they’ve told you! Read, re-read on how to centerline a cam. Acquire the equipment and practice with it or spend a little and take it to someone who (knows) can check it for you. Rest easy knowing it’s either ok or corrected. Assemble engine etc etc.
That’s my thoughts:thumbsup: