Does anyone out there have a '68 or '69 truck which came with a 396 stock? And if so what is the timing advance spec? According to Haynes the '70 version is set at 4 degrees btdc. But GM only put the 396 in the '68 and '69 trucks. After that it became a 402.
Me.
with automatic tranny engine warm, idle 600 rpm in gear set to 4 degrees before with the vacuum advance disconnected and the line plugged, all accessories off For standard shift, engine warm, idle at 750, vacuum line disconnected, tranny in neutral, again 4 degrees before TDC all accessories off. This for a '69 C-10 with a 396
Whitelightning
Thanks a ton (Well at least a three quarter ton) M
Just a note here. If your motor has been "re-built" it is common practice for the re-builders to reduce the compression ratio on that era truck engine to accommodate the lower octane fuels that came in the
70s.For instance, a 9-1 CR will usually be reduced to 8-1. This will necessitate a complete re-curve of the distributor advance settings.The Vacuum,centrifugal and static settings will need to be changed. If this is the case (does your truck run without knocking on regular gas?) you might want to buy a new BB dist.for a later low-compression truck,and gain the advantages of an HEI dist.in the process.
disconnected,
How do you reduce compression without changing the mechanics of the engine? And yes, my truck runs pretty damn good on 87 octane even though the carbuerator is not set up right for this engine (which is going to be another task).
Host
You don't, the pistons are changed at build. Watch the 87 octane till you get the carb done, I've burnt holes in pistons before(army facility engineers truck, '69 1/2 ton short bed step side, mogas has high octane)
Whitelightning
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