<html xmlns:v="urn:schemas-microsoft-com:vml" xmlns:o="urn:schemas-microsoft-com:office:office" xmlns:w="urn:schemas-microsoft-com:office:word" xmlns:x="urn:schemas-microsoft-com:office:excel" xmlns:m="http://schemas.microsoft.com/office/2004/12/omml" xmlns="http://www.w3.org/TR/REC-html40"><head><meta http-equiv=Content-Type content="text/html; charset=utf-8"><meta name=Generator content="Microsoft Word 14 (filtered medium)"><style><!--
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</o:shapelayout></xml><![endif]--></head><body lang=EN-US link=blue vlink=purple><div class=WordSection1><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>To add to these replies, which I agree with, it does depend on how you want to use the car. I faced a similar scenario with my 72B’s rebuild about ten years ago. Although it is an 18V engine block, I went with HC +0.060 pistons that I acquired from the UK (ebay dealer mechspec who also has an Internet site). This put the compression ratio around 9:1. I also used a 270 cam. I did not modify the head except to have hardened seats installed. I was looking for increased performance while maintaining the car as a driver. I was hesitant to increase the compression ratio too much as that would make it harder to find fuel for it, particularly in rural areas. This was based on previous experience – with my first MGB, a 1965 B, I installed an engine with a 10:1 compression (as I recall but it could have been higher, this was several decades ago). It was a fast car but back then, when leaded fuel was still available, I sometimes had problems finding a high enough octane fuel and in those cases, the car would keep running after I turned the ignition off. I don’t recall the octane back then but where I live now, the highest octane rating I can find locally (within a 30 mile or so radius) is 93 at two stations, 91-92 is typical for the rest.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>David Councill<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>67 BGT<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>64 B<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>72 B<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'>From:</span></b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'> Mgs [mailto:mgs-bounces@autox.team.net] <b>On Behalf Of </b>Richard Lindsay via Mgs<br><b>Sent:</b> Wednesday, January 11, 2017 8:03 AM<br><b>To:</b> Jack Wheeler<br><b>Cc:</b> mgs@autox.team.net List<br><b>Subject:</b> Re: [Mgs] Fw: MGB Question<o:p></o:p></span></p><p class=MsoNormal><o:p> </o:p></p><div><p class=MsoNormal>Hi Jack, et al.,<o:p></o:p></p><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>Thought I would chime in, philosophically. <o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>Just please remember that any engine design is a tradeoff between power, reliability, and cleanliness. Add to that known adage, 'drivability'. Old engines have fixed cam timing. That means the valve timing is set to the give optimum drivability - so maximum top end performance is not achieved. But if you tune for 5000rpm, the car is beast to drive at lower speeds.<o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>Okay, I've said what everyone else has said, perhaps except for this: What is YOUR goal? Decide upon that then build accordingly, and accept the limitations associated with that solution.<o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>Rick<o:p></o:p></p></div></div></div></body></html>