Ok, so I have the engine out and everything is going smoothly with the transfer when I realize, "hey, what cand I do to help performance?" I am installing a replacement b230 in my 86 240dl and was thinking about porting and polishing. I have heard that it is possible to do this at home and I have an extra head to practice on. What would be the benefits, if any, of doing some porting and polishing of my the head on a b230 and possible some work on the intake/exhaust manifolds? Any help would be appreciated.
Thanks,
Josh

There may be 10hp with porting and polishing on a B230 engine, but I doubt it.

Gasket matching the intake manifold and intake ports will help, but not much.

With a new cam after the port and polish...quite likely to see some gains if not feel them. Make friends with you local dynamometer guy or get a G-analyst or whatever it's called.

Read this article about DIY porting. Standard Abrasives and The Eastwood Company are two places you can get kits and/or parts to do it.

You'll get the biggest benefit out of port matching the intake manifold and intakes ports to the size of the gasket, and smoothing out the sharp inner bend where the ports join the combustion chamber. I haven't done this yet, but I do plan to. I'm only estimating, but I believe you can find an extra 10HP with a DIY job on the standard "small" Volvo head.

I'm planning to send some heads (100405 castings and 398 castings) to a local guy who has quite a reputation for finding increased flow on his flow bench.
So far what I know:
Misubishi inatke valves from an 80-84 2.6 four cyl (think Sapporo or down size Challenger will work and are 2mm larger. These won't work with Volvo valve spring retainers, however.
GM exhaust valves from the 2.5 $cyl will work and are 3.25mm larger. These work with Volvo valve spring retainers, but require GM valve locks (aka keepers)

Never port match your exhaust ports. The manifold must be larger than the port, with a mismatch.

Email me if you want to keep in touch.

iadr@hotmail.com