i picked up a 5.3L L33 SBC. I think it's rated at something like 330#tq and 320hp as it sits.
now this is just crazy to me:
with a simple whipple 2 screw supercharger (which isn't a traditional roots but it is close in fit and function) dialed up to only 9# of boost, and nothing else, the engine will plant 515hp and 480#tq... a camshaft swap on these things is super simple (as far as cam swaps go) - and an undramatic lift in the 290* range on a 110* LSA along with decent long tube headers and heads w/68cc combustion chambers and w/valve springs to manage both higher RPM range and pressure of the lift, and (dig this) we're talking 700+ ponies... this can be done in a weekend with fair ease, and a total cost of around $10k which includes the fuel system upgrade (pump, regulator+return - if you have the flexfuel injectors, you don't have to swap them). Now that is steep by anyone's estimation for a daily driver intended to remain that way, but.... more than doubling HP and TQ in a weekend with what amounts to bolt on's and no machine work? this was unheard of even 20 years ago. the L33 has been taken to 1400HP and managed it. This is with all the above work along with running 108ran fuel, and an aggressive tune, dialing up the boost to just shy of +2 atmospheres, and swapping pistons (primarily as it's the OE rings that cause issues at the higher boost levels+heat- the gap is too shy which causes them to break up and take pistons and cylinder walls out when they go, the idea is you run a higher quality forged piston with rings that have a bit more gap and allowance for expansion at top end while suffering greater blow-by at low end). By the way, the L33 that was pressed up to 1400hp? They were trying to blow it, to see what the internal OE components could handle (pistons/rods/crank). They thought they had, but what had actually happened is they bounced the rocker off the post on cylinder 8 and bent the hades out of a lifter rod, which allowed near zero compression on that cylinder... they discovered it as they tore it down to inspect, which is right at the beginning of a tear down. knowing they wiped that lobe on the camshaft, they went ahead and tapped a new rocker post in and girdled the whole valve train (the OE is pedestal), and put it back on the dyno... they were still making 1000+HP runs on that engine before they 'lost interest'. all of this from a freakin' 5.3L engine w/ zero machine work to the block other than testing it for leaks prior to building. they didn't even do that until attempting to break 900 (and swapping pistons/rings due to expansion they knew was 'next' to go if they didn't).
somebody mentioned exhaust... don't get me going on exhaust- it is one of the most interesting topics to me about engines, and because it is so universally misunderstood.
as it is, this tahoe i've been daily driving is about to get a lot more fun.... as soon as i find some white space, and as soon as my whipple is delivered... the estimated delivery date is February- they are a bit behind.