see also http://forums.turbobricks.com/viewtopic.php?p=26597#26597
&
http://www.geocities.com/iadr1/techphotosmystuff.html

I'm part way through setting up this conversion. I'd probably be done if the rest of the car were fresh and the b20 didn't run so well... and I had money, and, and, and...yeah...

My thought is that the leaned over conversion is a bad method, as it requires way more mods, and the M46 ratios- how do I put this... suck.

The advantages of an OHC as I see them are: never have to buy another $140 head gasket, never have to battle timing gear failure, no need to buy aftermarket cams- the A, K & T are excellent, no need to buy lifters. The 96-97mm bore on b23's is way bigger than the max of 93mm on OHV- which requires a $$$ bit of machine work, so more displacement. A proper cast iron turbo manifold is available (in the wreckers, no less), as are a major selection of pistons- flat, & a ton of combinations of bore, CR & sizes of dish (b21, b21ET, b21ft, b23E, b23F, b23ft, b23et, b230E, b230ET, b230K, Aq151). Service pieces like gasket sets are cheap and easily sourced. Not so with a number of the desirable b20 parts- thin head gasket, decent intake/exh manifold gasket, steel timing gears.

I think the engines got bad reputations running in overweight cars, and in smog trim. Drive a Canadian, Aus, or Euro-spec b23E...

I don't know anyone who's gotten 200K out of a set of b20 gears, btw, and the belt is cheap.