Well, today I took delivery of the new engine (thanks again Justin!) that I intend to put in my somewhat recently acquired red '70 145. The engine is used, but has fairly low miles (we think) and is said to be a runner. Actual condition is a mystery, as is what all has been done to it.

The engine itself is a semi-metric (arg...) 8 bolt crank B20 from a '74 or '75. Quick and obvious modifications would inlcude double valve springs, ipd pushrods, nice shiny ported intake & exhaust ports.

Slightly less obvious stuff would inlclude steel timing gear... thanks to a strong magnet (aluminum timing cover still in place). Add another to the strong magnets uses list... #1589403 I think.

And.. perhaps concerning, perhaps not.. is how much has been shaved off the head. I actually noticed how thin the deck is below the plugs right away, so I did a quick search to find George Downs' list of B20 head thicknesses, but lost it since I found it. Quickly measuring the head itself on this engine, I came up with ~3.225 between the bottom machined surface where the head gasket mates to the top of the machined surface for the valve cover gasket. That would put it at about 1/10" thinner than the highest compression B20E. Seems like that's an awful lot. But would that be an approprate thing to do for a big bore kit?

I also did a rather crude measure of the cam lift...by dropping a pushrod down the hole and measuring the distance from its top to the valve cover gasket surface... I came up with ~.3" lift on the exhaust, and ~.31 on the intake. WOuld they normally be the same? If so, I'll assume its a measurement error, and take an average. Which, with the *1.5 from the rocker assembly, should be a lift of ~.46". According to my research, that would put it in the vicinity of the Volvo R-Sport cam, which I know nothing about. And...of course, I have no way of measuring duration.

The engine is reported to be overbored to 2130...but I don't want to remove the head to look. I don't have a headgasket, but I'm assuming it is. And also might have a stroked crank, but not sure about that. My guess would be no with so much taken off the head...but...?

I also have no idea as to the valve sizes, but I assume they are big ...again, don't want to take the head off to see.

Questions being... Do my measurements make some sort of sense, and what can I expect out of such an engine assuming it is in reasonable shape? What sort of compression might I be looking at? Would it even be streetable? Any other things I could be checking out without a teardown? And...with that sort of lift, and that much off the head, could valves hit pistons if the timing gear went? Of course, being steel the gears ain't gonna go, but curious anyhow.


I'm basically planning to just stick it in as is and test it in the car, but would like to get any insights and/or precautions first. I've never dealt with these sorts of performance modifications...

Thanks so much for any thoughts...
-Matt