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TR5/TR250 TR250/6 head identification

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G

gjh2007

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While tinkering on my 250's rear axle I peaked under my workbench at my spare engine & heads & got somewhat distracted.

Here's my question. The head that is on my very early block has the following castings "V3059" "Stanpart" "307837" & a circle "B" Under the valve cover. I thought I read something about the circle B heads being a good one to use.

My other spare striped head has "V3267" "312388" "218227" & what appears to be an oblong "O" under the valve cover.

Let's say I was planning on redoing a head to swap onto my 250 & both were in the same condition. Is there any advantage to one over the other?

Thanks for your input.
 
Hello Gary,

from what information I have, your first head is not on the list, 312388 as a cast number is a Mk2 P.I. engine and should be 3.4" thick, which is a high compression with 32mm exhaust valves. However a stamped 218227 is a TR6 head, low compression and 3.535" thick also with 32mm exhaust valves.
I would select which head gives the higher compression ratio, but bearing in mind that shorter push rods are neede for a 3.4" thick head if you have a thicker head already installed.

Alec
 
Alec,
The early US heads had the narrow spacing on the inlet ports. I think the PI heads all have the wider spaced inlet ports. Can you confirm?
BOBH
 
On quick inspection the manifold gasket I have fits either head, so the porting appears to be the same, where do I measure the height of the head? & should I measure the dia of the valves on the spare that is stripped?
 
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