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Thank you Mr Stanpart!

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70herald

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Yahoo, I found a brand new head casting!! Still in its 30+year old British packing grease. Happily it has the correct sized valve holes for the valves I already bought.
The only thing I need to do now is get it machined to raise up the compression ratio a bit. The head is a 1500 head so it has slightly larger combustion chamber volume than what I need for a 1300 engine but even my sort of vaguely competent machine shop should be able to handle that!
Of course being straight out of the '70s it doesn't have exhaust valve seats but since I can still get leaded gas here for the next year or so, I am really not worried.
Now I just need some time.....
 
I drove my TR3A for 43,000 miles on un-leaded before I got too much valve seat recession and had to put in the 4 hardened steel inserts for the exhaust valves. Depending on how much you plan to drive your Herald, you may be able to delay this operation for quite a few years. When I had mine done, I also had them put in 8 new valves for un-leaded, 8 new valve guides and the engine rebuild shop skimmed the head and ground in the new valves and seats. That was 57,000 miles ago and I have not had any issues since then. The valve clearances have stayed correct since then with a few valves needing only minor corrections to re-gap them to specification.
 
I was told by the machine shop that was prepping my heads during my now two year old motor rebuild completion that I should live so long as to need hardened valve seats and special valves for the unleaded gas. So I did not select this procedure and at about 4000 miles driven per year, I hope to live so long as to need it done later.
 
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