From my experience it's hard to beat the turbo stuff if you're willing to fab a little.

The most expensive part isn't making 8 sec power, it's the 8 second fuel system, Trans, axle, suspension to make it all hook, chassis to cert 8.50, etc.

Power is pretty easy.

Grab a 6.4L Big Gas out of a junk yard truck. Has strong short block, hellcat head castings, add a cam and let ot rip.