High-Revving 5.3 Vortec Combination
 

I'm looking to build a high-revving, high-hp 5.3 liter vortec based motor. I'm going to be running a t5 manual transmission (no complaints please) behind it, so I don't want to make more than about ~330 ft lbs. of torque. BUT, I'm looking to maximize top-end horsepower. What camshaft and/or combination of parts will help me achieve my goal? Ideally, I would like 425 hp.

Stock, stock and stock.

425 horse and 330 ftlbs is kinda off the map considering the 5.3 makes very close to that, stock.

You might consider finding a 4.8 crankshaft and rods. Bore your 5.3 to 3.898 (LS1 bore) and use LS1 pistons....stock or forged. Complete the long block with a nice port job on your stock heads and a 02-04 LS6 cam/new LS6 springs. Your stock intake with headers/full exhaust will work well with this combo. Finally get yourself a nice tune. This combination will be fairly inexpensive and will exceed your performance goals.

Thanks for the input. I've haven't purchased a 5.3 yet, but I've decided to go with a 4.8 instead. I'm going to use the following parts: ported ls2 intake, patriot performance cnc-ported 5.3 heads, and an ls6 cam. Should put me at about 400hp and keep torque in the low-to-mid 300s.

There are a lot of cams available that are better than the LS6. Are you talking 400 hp at the crank?

Yeah, I'm looking to make around 400hp at the crank. I've got a T5 Z-Spec, and that's considered to be its limit in the mustang community.

sell the currently working T5 and buy a T56...... or you will be selling a broken T5 soon enuf and still buying a T56 :usa:

A healthy 5.3 will chew up even a World Class T5 over time.

No doubt, only way that t5 is going to survive is if you shift like a grandma...and performance shifting or clutch drops and you will be in trouble! Even a 4 speed would be stronger than the t5....if you must use the t5 than get the lightest flywheel possible to cut down on your rotating mass bc the heavy truck flywheel will blow that t5 up! Good luck man

LS2 intake is a POS. You will be trashing that T5 soon and wishing you'd gotten a t56 anyway. Then guess what? You'll wish you'd built a standard bore motor instead of downsizing.