nm9stheham said

Typing at the same time....

Thank you... it restores my faith in humankind LOL. I appreciate your listening.

There is a set of those rods up in Strasburg VA advertised on FABO that might be had at a fair price. I am trying to think of a set of pistons with higher CR that are the same weight as stock, so that you can avoid the price of re-balancing but am drawing a blank. That is the chronic parts problem with the 318; cheap high compression piston options with stock weights.

The other ones that could be considered are very early 318 LA pistons like '68-'69 that have been reported to have a much higher compression height; they should balance out fine. But finding those would be a challenge; the standard replacements are not that, even if they are listed to cover '67-'69.

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nm9stheham said

BTW, you asked about lower CR's for trucks. IIRC those are listed in the Silvolite catalog; you can see the lower compression heights listed.

Trucks spend most all of their operating time at low RPM's near the peak of the torque curve with small cams. The small cams increase the DCR at low RPM's to optimize this. But the RPM being around the torque peak puts you the closest to detonation.... add in some poor octane fuel from a fuel pump in the 60's in the middle of no-where and it wants to go 'ka-boom'. So I presume that is why the CR was lowered in those uses.

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