Suggestions, please! Stock 1972 142S / M41

Want a modest 'Street Performance' type engine build, using available off-the-shelf parts.

Block: How much overbore?
Head: Port & polish?
Cam: ?
Intake: ?
Carb: ?
Header: ?
Exhaust: ?

Many thanks for your advice.

Depends on how much extra power you are looking for. I have a B20E which is the highest output version of the B20. It is more powerful than a B20B; but, not by a lot and its still a noisy engine with a narrow power band (compared to modern engines). If you are looking for significant reliable power increases your low cost solution will be a more modern engine transplant. Picking an engine and gear box from a car with a similar in-line engine configuration will make life simpler. A Mazda MX5 or Saturn Vue / Pontiac Solstice come to mind (salvaged MX5s can be hard to find). The turbo versions of the Vue / Solstice would toast the Dana 30 differential so stay away from them unless you want to do a complete drive train. There are other options such as the Ford Lima engine. The Volvo B230FT engine is possible; but, probably more work because of its tilt (turbo interference with the right inner fender) and the intake manifold - brake booster interference.

If you take out the B20, you don't have a Volvo anymore.

The B230FT sucks because cylinder head is terrible. B234 if you want a better Volvo donkey, although I'd stick the B234 head on a B23 & a mild stroker like this:

http://www.topplocksverkstan.se/volvo16vrc.html 300+ BHP without a hair drier.

Will stick with a Volvo engine. A modest power increase is desired. Car now has a port-matched F head, headers, WEBER 38 DGMS with Cannon intake, D cam.
Would like to try a TINUSTUNING cam, maybe the TT5, as they have improved on the 50 year old design of the D cam.

You don't have to spend a fortune to get some positive results. A '72 142S should have HIF SU carbs. They are fine. To get more oomph from your 2 liter - raise the compression ratio and install a healthier cam. I think your stock compression is something like 9 or 9.5 to 1. If you mill the head 40 or 60 thousandth of an inch that will bump the ratio to around 10.5-11 to 1. That depends on the starting ratio. I think the "green book" lists the head thickness (for lack of a better term at the moment) - that is -- from the head/block mating surface to the machined surfaces on top (head bolt or valve cover machined surfaces). That thickness will determine the compression ratio. I found when rebuilding my B20 that for every 20 thousandth taken off raises the ratio about a half point.
On my engine I went a bit further and found a carb type cylinder head (maybe from a Canada car?) that has the 44mm intake valves (like a Fuel injection head) over the normal carbed 42mm and did some minor porting and port matching on the exhaust side. You don't need any kind of wild cam - the "K" cam works well with carbs. The split exhaust manifold may not look sexy but is very efficient. A switch to the later Bosch electronic distributor or a good aftermarket will be a plus. I wouldn't go for any radical boring - at the most that will get you a few cubic inches - but make the block un-rebuildable. A few simple changes can get you from the original 118hp up to about 130 - something you'll feel. Good Luck with your project. - Dave

"the "K" cam works well with carbs": This is very true because it has the same seat to seat timing.

Low Compression, closing the lobe centres up a little is helpful.

High Compression, a longer exhaust lobe can be used because high compression & high octane burns faster, so opening the exhaust valve earlier helps overcome the poor exhaust port flow.

I thought of one thing additional -- budget enough to have hardened seats installed on the exhaust side to better match todays fuels. - Dave

How much money you got???

What have you got now?

Strombergs? SU's HS6 or HIF6?

This is a good starting point. It was one of the first things I read when I started building my 145. The DCOE intake/carb setup is a bit lavish, but you can always opt for the more "modest" alternative, the Weber DGV.

http://www.vclassics.com/mppe1.html