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Old 08-18-2007, 08:25 PM   #6
loosecannon39
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Join Date: Jul 2007
Location: texas gulf coast near La.
Posts: 6
Red face Re: 305 v6 GMC motor

As a former Houston Lighting and Power mechanic, I worked on a lot of these engines. Previous posts were correct. It is a torque monster, and a workhorse, but heavy as an early hemi. 2 cautions. Never -Never, allow one of these to get hot. Every time it happens, they crack the heads between the intake and exhaust valves. Also, if you have a miss that seems to be a vacuum leak, pull the valve covers and check to see if the Donaldson valve has spit out its innards. It is their version of a pcv valve, and screws into the head,directly into the paired intake passages. The slow turning, long stroke engine caused major pulsations in the intake system, and the valve cycles to violently, it regularly breaks through the tabs that hold the innards inside. Also, I've seen people pull the valve, and just put a pipe plug in the hole. Don't be tempted to do it. Finally, the plugs are on the intake manifold side of the head instead of the exhaust, and you must be extra careful installing the intake manifold, and gasket, and retorque it regularly. They commonly work loose and allow the very thin gasket between the two passages to be sucked in to the passage. A little attention goes a long way. This is a true workhorse, if you give it a little attention
REGARDS
DAN
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