Not only is an intercooler ineefective for a draw-thru, but it's unsafe. I've heard that the atomized fuel in the intercooler can ignite from a backfire and actually blow the intercooler apart (nasty shrapnel, etc). Bottom line is no intercooler for a draw-thru.
I for one would be thrilled to hear what's been done to the motor and how it rides on the street. I'm still putting together a mostly-streetable turbo engine from an ATP kit as well and I'd like to know how the fuel consumption is, what carb you're running, what fuel pump/regulator, how it goes and stops, what ignition system and timing is on the bike, etc.
I'm 99% sure that's an ATP kit, and it's an early kit because it has the log-style manifold. I've talked to Terry at Mr Turbo and he told me they didn't actually offer a CB750 "kit". They did one for the 550, and they sold parts, but that setup there is likely ATP.
The ATP kit for the street was allegedly "bolt on and go". I've got a few mags that talk about it and supposedly you didn't change anything, not even the ignition system or timing, for up to 4-5 pounds of boost.
The oil-cooler is definitely a good start. If you wanna go through the trouble the best way to cool the bike would be water/meth injection. There are some fairly small setups for the tuner crowd with integrated pumps and all. It's a bit of extra plumbing, but not too bad since it's a single manifold anyway. Might be more current draw than the CB is good for though. I looked into them, but decided ultimately that it was just too much extra crap to carry along.
Another way to keep temps a bit better is more oil capacity. A larger oil tank, or secondary reserve tank. There was also back in the 70's a deeper pan for the 750's (not an auto pan, they don't fit the K's) that also had more fins on the inside. That would help. I'd imagine you can have a shop machine you a pan spacer and get another quart in the pan (with a longer pump pickup too of course) and that should help out.
Definitely check the timing and fuel mixture. Lean mixtures make bikes run hot, and forced-induction aggravates it. Also, the timing is going to be retarded somewhat because of the turbo. It might be that someone has retarded it too far to make up for running crappy fuel. That bike's gonna expect (and need) premium to keep the knocking down under boost.
NitroHunter is definitely more the expert on turbo SOHC's here, though.
