408 rwhp dyno

Anyone dyno their 408 on a chassis dyno ? I did mine 4 weeks ago and the result was 391 hp and 389 lb ft. Motor is 10.5 to 1 ported, 2.02 eddies m-1 intake, 750 holley hp and bullit hydraulic solid 282 -292 @108. Also it was a mustang dyno.