The Stovebolt Site Forums The Shop Area Engine Shop New GMC 305 question -- Plugs and gap?

Can anyone tell me the correct plugs (and gaps) for a '65 305 V-6? The engine is in a 4000 series (ton and a half).

The engine is not running quite as smoothly as it should and has a little bit of a miss. I am going to pull the plugs to check the gaps, porcelain for chips & cracks, etc. But I have no idea what the gaps are supposed to be, actually ...

A quick recap -- The engine has new cap, rotor, points, condenser, coil, wires and plugs. Also, a freshly rebuild carb with a new mechanical fuel pump with a brand new electric back up (On the way to a show last year, the truck's mechanical pump failed and packed the crab full of diaphram bits, caused an engine fire and caused a lot of issues going home most of which have been corrected now except for this missing. A professional truck mechanic did the compression test, rebuilt the carb and double checked the timing and point gap. We have not yet pulled the plugs and double checked them.

Thanks,
John

I can get them tomorrow John if no one comes up with it between now & then. George

here you go john i just dodged the rain drops out to the shop c44ns plugs and .035 gap

Just a thought - when was the last time you adjusted the valves?

Old Dog & George -- Thanks -- I hope nobody got too wet. Was that AC-Delco on the plugs?

David -- Good question. They've not been adjusted since I've owned the truck and may not have ever been adjusted since they were set on the assembly line. Remember -- the truck has 10,000 miles on it -- 2,000 since I've owned it. What should they be set at?

v/r
John

Valves don't usually get too tight on their own, which would be the only way they would cause a miss. If they were too loose then they would be obvious, too much noise,
Scott

I thought that a loose exhaust rocker could cause the engine to run rough, and it seemed like one thing not already done.

John, I have no idea what they would be set at - just talking shop and learning from the best.

yea that was ac delco ,i didn't worry to much there wasn't any soap in it .

Here's a copy of a page out of my '72 GMC 4500-9500 owners manual.
http://image62.webshots.com/662/7/43/48/2348743480103559715JDkNRV_fs.jpg

if you need more let me know.