Quite a few guys with 35's on normal F150 and upgrades making around 500WHP and 600WTQ on current Gen 1 engines out there on pump gas due to limit of stock fueling.
You will be super surprised what this thing will do on E and tune.
The wheel tire combo will impact the dyno but the gearing/trans will help massively at the track and 1/4 mile times since we don't race dynos.
I expect 12's out of the Raptor very quickly provided tuning becomes available. I'm praying Cobb jumps into the fray, I bug their Ford Ecoboost specialist almost biweekly on fb
Long term I'm looking at the Motec M1 ECU to control fuel/spark/TC and bigger turbos. Long term goals are 11's and 800WHP for me, gotta finish my CTS-V build first shooting for 1300++ WHP and back halving my 2011 coupe currently.
I am aware that we don't race dynos. My comments were aimed strictly at your example of a 600whp Flex. I'm just pointing out that it's going to take a lot more power in a Raptor to get to that level at the rear. And the fact remains that a truck with 4.11 gears and 60 pound tires is going to accelerate faster than a truck with 4.11 gears and 90 pound tires. So you really can't dismiss the dyno results any way you slice it.
I would recommend against the Raptor as a platform for that kind of project. It's really not built for quarter mile racing.
I'm waiting for them to bring back the Lighting. Hopefully with a 5 liter EB. That would be a much better starting point for a street truck.