[Fot] GT6 vs TR6 blocks - interchangeability?

[Scott Janzen]

I am rebuilding my street TR6.  I need to replace the block - it’s sleeved, bored 30 over, and needs another bore, and I would rather just start over as it’s not original to the car anyway.  It’s a later block with the horizontal reinforcement cast into the manifold side, and the car is a 1970.

I have another block, allegedly from a GT6, has a KD number indicating GT6, but it has the concave/convex “blowouts” on the manifold side to clear a TR6 crank, which none of my other GT6 blocks have.  It’s also 25 lb heavier than a GT6 block, and has notches at the bottom of the piston bores to clear the con rods, which I’m pretty sure the GT6 blocks don’t have (though I don’t have a GT6 engine apart and apparently my memory is not that good).

So, here’s the question - can I use this for the TR6 - is it the same block where at some point the factory used them interchangeably?

Or, do I need to find another block?

Scott Janzen
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