The 1947 - Present Chevrolet & GMC Truck Message Board Network - View Single Post - Truck running poorly under load, need help.

rich weyand · 08-25-2016, 10:04 PM

That is about right, although a little low for a non-emissions (1975) engine, if that is with the vacuum advance disconnected.

You did measure it with the vacuum advance hose disconnected, right?

A better value is between 12 and 16. Until it knocks, more is better.

08-25-2016, 10:04 PM	#18
rich weyand Registered User Join Date: Apr 2014 Location: Bloomington Indiana Posts: 1,041	Re: Truck running poorly under load, need help. That is about right, although a little low for a non-emissions (1975) engine, if that is with the vacuum advance disconnected. You did measure it with the vacuum advance hose disconnected, right? A better value is between 12 and 16. Until it knocks, more is better. __________________ Rich Weyand 1978 K10 RCSB DD.