2 barrel to 4 barrel
This was a bit more than a carb/ intake swap but it is on a 318. For MY purposes it was a huge wake up for that engine.
83 D250 2wd 727 3.23 and 32" rubber (235/85-16 10 ply). It ran more than decent for what it was and how it got used stock, as I bought it.
I swapped EQ heads into it, a new, stock replacement 360-2bbl cam, the 1.6 rockers that the magnum heads would normally come with, a regular performer (not rpm or air gap) a Carterbrock 625 carb, hooker super comp headers and true 2-1/2" duals all the way to the back bumper, std issue muffler shop turbos.
While I never had this on a Dyno, the difference before and after was more noticable than night and day.
That truck was overloaded more often than it should have been, and I towed a car trailer often, and when I did so it was always likewise overloaded for what it was.
More than one person who seen that truck thought I had to be lying when I told them it only had a 318. But it did.
And mpg went up from stock/ especially when I wasn't towing or hauling.
I sold that one to my cousin, and my son ended up buying that truck back some years later just for that engine. It's now in a 72 fury wagon
Other than the cam swap at around 133k miles (all work listed was done together at same time) the rest of the short block has never been apart/, pistons, rings, rod and main bearings, are the very same ones the engine left the factory with in 1983.
But everyone's wants for their vehicles are different. That 318 definitely exceeded my expectations.
Between the kid and I we have a complete rust free cab, doors, bed fenders and hood stashed away that we could put it back on the road... The original body has been crushed but he still has the rolling frame.