What's the budget formula for a 4.8 LS + manual swap into a Challenge car, and are 4.8s still cheap?

Yes, 4.8s are still the budget pick. Speedway says they can often be found for as little as $200 at the salvage yard, which makes them the cheapest LS you can buy. 4.8s were never built with AFM, so there are no AFM lifters to worry about.

The engine side: The 4.8 shares the 5.3's block design (six-bolt mains, 3.780 in bore), cylinder heads, intake and PCM. The differences are inside: a shorter stroke (3.267 vs 3.622 in), different rods and a different cam. Stock, the 4.8 makes about 270–290 hp; a cam, springs, injectors and a tune are the cheapest way to add power.

The manual side: an LS needs an LS-specific bellhousing (a factory T56 bell or an aftermarket steel one), a clutch, a flywheel and hydraulic release. The Tremec TKX is the most popular LS swap manual today; a T56 may need firewall or tunnel work.

Build your number with the swap cost estimator.