Hi Dave,
Do you mean bore out the 821 block to accept the existing 843 liners?
I’m unclear where you’re going with this?
First thing to do is assess the current status.
Re the 843:
The crank appears to be serviceable.
Unknown wear on the pistons/liners, valves etc. & many other items.
Unknown coolant circulation.
Missing camshaft.
N.B. - Lots of caveats here because diagnosing things over the internet via strangers looking at pics needs to be taken into account also.
Suggest taking the important parts to your machinist and have him measure stuff & do an assessment. They usually don’t charge much for this and it’s vital.
Skinning the cheapest cat:
Assuming everything measures OK, reassemble pistons/liner, new bearings etc. Refurbish/renew whatever is needed, install a mild cam, Weber/Dellorto 40’s, headers and go. I’d expect this to be surprisingly decent.
Skinning the cat differently:
Using the 821 block, build a 17TS spec. engine as I mentioned earlier.
Install the larger valves, Weber/Dellorto 40’s & headers, same as before.
Skinning a bigger cat:
The 843 uses the 84mm spigot so there’s little available off the shelf in terms of just dropping in a set of pistons/liners as is usual. However, why not take advantage of that?
Have some custom 80mm pistons x 10.25 compression made and bore out the 843 liners to suit. That should provide about 1689cc’s.
Install a 17TS cam & larger valves, Weber/Dellorto 45’s & headers etc.
All these “cats” would be entirely streetable. This last option is probably the best bang for buck and perhaps cheaper than building a 17TS.
Thoughts JB?
