Ford FE 352. Upping the cubic inches?

I'm 16 years old, have a '66 ford f250 with a 352FE in it. It's got a remanufactured holley 500 2bbl and headers going on right now. Everything internal is stock. I'm looking for more power out of this grandpa of a motor. Not saying it's a bad motor but it just doesn't have the power I'm looking for. I don't have the money to get it bored out or professionally rebuild but I've though about changing the crank and rods out with a 410 or 427 crank and rods. Can that be done with a 352? I know you can put a 390 crank and rods in to make it about a 360 but if I'm going to tear down this engine I want something more drastic than 8 more cubes.

Credit Score 736 is that good enough?

My mom has a credit score of 736, and I wanted to start mapping out cars she can afford to get me, monthly payment wise. Do salesmen lower the payment the higher your credit is, I do know dealerships lower interest based on how high your score is. My mom has been a school teacher for the past 16 years, a nurse and sells Mary kay products. I know she makes over 60,000 a year. The cars I want the most is a Mercedes Benz CLA 260 Coupe, BMW 328I, or a Ford F250 unlimited. She just bought her 2 cars in the past year she just doesn't make things understandable for me. Thanks for the info in advance.

Added (1). It's a Ford f 150 Unlimited!

2014 Ford Super duty 6.2 mpg?

Any word on what the mpg's are on the 2014 6.2 Super duty? Specifically a Supercab long bed 4x4 with 4.30 rear axle

Commercial's License Required? Yes or No?

2014 Ford Super Duty F-250 XL 6.7l PowerStroke is a truck that has a 14,000 GVWR.
Would i need a CDL for this pick-up.
Also would it help to have a 9,900 limit weight Package?
Using a vehicle for:
* Tow/Haul
* Commercial interior/ Hard touch plastic
* Plowing
* Landscaping
* Heavy dutyCommercial s License Required Yes or No

How to move two trailers at once? I'm moving?

I have a ford f350 and am renting a big u-haul to move my stuff. I also have a boat(no I'm not selling it) it's my only vehicle, what's my best plan of action here? Not paying any company to help either.