Actually the oil feed line comes off a distribution block that threads into the 1/4" NPT hole at the back of the head...and this hole is on both heads, so that isn't really a difference. To explain it a little more...n/a heads have a "closed" chamber (heart shaped) where the turbo heads have an "open" chamber (D-shaped). The turbo heads also have hardened valve seats on the exhaust side, and the valves are better. Other than that they're basically identical.
A turbo head will give you power only on a turbo engine (well, in most cases). With lower compression on the turbo 2.3, you can crank the boost into the 20ish+ range. Turbo with a N/A head, 10-12psi is about all you're going to get. To see the differences in the chamber design, check out http://www.binaryweb.com/fordtech/cyl_head_bowl/index.asp
The SVO's came stock at 15psi... I forget when the T3 runs out but I want to say around the 20-22psi range.
pffft. Anyone ever calculated the actual difference in compression between the NA heads and the turbo heads? The difference is minimal, and on a 9.0:1 NA engine, the turbo head will drop you to around 8.7:1. The turbo head flows a bit better, so you can expect a bit more top end (only sightly less pathetic) and possibly a little less torque everywhere else. On the other hand, an NA head on a turbo engine will get you from 8.0:1 to 8.3:1. That alone won't make the difference between running 20psi and 12 psi. Simply not true. Heck, I milled my NA head, and was running probably 9.5:1 compression and still getting away with 12-14 psi of boost. lol. Most of the difference in compression is from the dished pistons of the turbo engine.
