Where does the extra 30 ponies come from in 405 LT5?

[Brett]

How does the '93-'95 LT5 make its extra horsepower?

I checked around the model center, but couldn't really find anything specific. Maybe I missed it.

I could be wrong, but I thought I remembered once reading that part of it was the exhaust was more aggressive.....and if so, wouldn't that advantage pretty much be nullified by adding an aftermarket exhaust anyway?

 

[Aurora40]

The exhaust on the '93-95 was less restrictive. The resonator on the '90-92 necks down considerably more. The headers are also different. I imagine the mufflers are less restrictive, but maybe not.

Also the plenum and injector housing passages were larger on the '93+ motors, and I believe the intake passages in the heads were as well, though I could be mistaken.

So yes, you can get that difference back if you choose to. It actually makes the gains more impressive if you do the exhaust and port the plenum and injector housings, since they are both more restrictive initially. It costs the same whether you have a '90 or '95, so you get more bang for your mod buck on the earlier motors. Though you have more off the bat on the later ones.