Hi fellow Brickers,

I am in the process of restoring one of two of my P130’s.

My ‘daily driver’ P130 has a B18, single stromberg, and a 5-speed M47 fitted. In the higher speed regions the B18 lacks torque.
On my ‘best’ P130 I’ll be using an AW71L tranny. The M47 has ratio 0.81:1 in 5th while the AW is 0.69:1 in overdrive. Since I’ve got a Lock-up torque converter this is the ‘true’ reduction ratio. Because of this the engine in my ‘best’ P130 will need even more torque.
I’m not willing to use an other rear axle / ratio, since I was able to purchase a real good, but real cheap Limited Slip differential (ratio 4.1:1) which offcourse I want to keep.

I do have a good shape B20A, with cast iron manifold with double SU’s on the shelf, but I want some more power then that. (btw can I cut the thing in 2, to keep the inlet side a bit cooler) Concidering a stallspeed of something in between 2000-2500 rpm I guess I want to gain torque in the 2000-3000 region. (Low end torque is what I like anyway: also with the manual I shift up very quick, don’t like revving)

My plan is to use a late B20 (from a 140), and bore it to fit B21 pistons, and perhaps use the injection system and manifold. Keeping my objective of increasing low end torque in mind, these are my questions:
1) Do all late type B20 head have big valves/ports? Or are early injection heads better/bigger?
2) Will any standard B20 head have sufficient flow for the B21 piston-setup?
3) I read that the combustion chamber has to be modified to fit the bigger bore? How, what and where do I have to cut out?
4) Here (Netherlands) I’ll be driving LPG so no worries about pinging. What should my compresion ratio be?
5) Since I need hardened valves and seats because of running LPG, what would be the best head vs. valve size (in+outlet) combination?
6) What about manifolds? Inlet: injection? Outlet: spagetti / free flow? Or should I use standard exhaust manifold for low end increase?

(Perhaps I do not need any bigger valves and/or prts at all since it’s mainly low rpm power I’m after)

What are you people thoughts?

Thanks in advance, Ben Flierman
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Volvo P130, 1965: B18A + tilted M47, Volvo P131, 1969: in the proces of rebuilding: B20 + AW71L , (www.knutselsmurf.web1000.com)