it depends on how much horsepower you are making. However once you use block guards, or close the deck on a honda engine, you basically just turned your car into a Drag only application. Close deck blocks don't do well sprint racing, road racing, etc. From experience they hold too much heat in the engine and does not allow to cool down fast enough for long spirited driving like road racing. As far as drag applications, they are what you want for high boost, high horsepower, 1 pass, kind of racing.
i'm not saying it's a bad idea. Paul knows what he's doing. I'm just telling you from the experience that I have... Most of the engines I build really get put to the test. They don't just do a couple of freeway passes or a pass down the drag strip. They often times get driven hard for hours pinging the rev limiter non stop around a road course.
These guys with sand rails, you gotta remember, they aren't building a street car. They are building a toy to go fast. You're comparing apples to oranges if you are thinking that would be something to compare to.
Just like Formula 1, Nascar, and than your funny drag cars. All their engines are built differently. They all have life expectancies. They aren't built to last long. They are built to get the job done and thats it. When the season or event is over, they put in a new engine.
Now if you're planning to boost 20+lbs, make over 500whp, 500ftlbs. Than yes, sleeve the block. As far as longevity and reliability, throw that out the window.
I have a J35 that makes over 330whp, and over 300ftlbs of torque naturally aspirated. It's a open deck, sleeved, with pistons and rods. I beat the crap out of the engine. I broke it in on the dyno and at the track. I put about 10,000 miles on the engine so far, 8,000 of it was at the race track... It's still running strong.
block guards should only be used id the block is to be torn down a season or two after. the have been proven to oval cylinders and if they are not welded in you chance it dropping. block post or MID's ftw!