Questions from a Newby!

[kf4jfk]

First off I want to say I have fell in love with this forum. There is so much valuable information that I find myself losing sleep, but i'm not complaining. I have been searching for my next toy for some time and I finally found it. Its a 1964 GMC Fleetside Longbed w/ 305ci V6 and a 4-speed.

Let me add that I have tried searching this forum and other sites on the web for the answers to the following questions, but with no success.

Now the questions:

1)I know that these engines are rare and only were in the GMC trucks, but I cannot find any specifications on the engine. I am needing to know what weight oil and capacity. Any recommendations Accepted! I have checked the "6066 GMC Guy" website, but have had no luck. The reason I need the capacity is the oil pan has been knocked in from the previous owner. It does not leak and i do have good oil pressure on the gauge in the cab. Can anyone help?

2)I am loving this 305 V6 engine. What a power house! It has a Rochester 2 barrel carb on it. Is this original? (I had to pull it off and clean it due to the truck sitting for some time before I bought the truck.) The only reason that I am questioning the originality is I cannot slow the idle speed down. I have backed the idle screw all the way out and it still idles at 1300-1500 rpm. I have checked the pedal linkage and seems to not be in a bind. Other than the idle speed, the truck has a pretty decent powerband.

I appreciate any all help. I am truly stumped with these issues. I also want to apologize if I put this thread in the wrong place. I am new to the forum life, but am looking forward to busting some knuckle on my new bucket!

Thanks so much in advance for everyone's help.

[wc63]

welcome from az. capacity wise, i would just check the dipstick as i fill it. i think its about 5 or 6 quarts. the weight of the oil normally depends on climate (as far as i know) hotter climates need thicker oil while colder climates need thinner. some people use oil with higher zddp for older engines.
"There are a number of them:
Valvolline VR1 Racing Oil is available in 10w30 and 20w50 grades.
Brad Penn is available in a lot of grades.
Joe Gibbs Racing has a Hot Rod oil with high zddp.
Castrol has a 20w50.

Of these, the Valvoline is probably has the widest availability. It is at most
AutoZones, but they usually only stock the 20w50." i copied that from jolly's message board (6066gmcguy.com) i would seriously consider joining that board if you plan on keeping your 305gmc.
i am pretty sure the stock carb on these was the Stromberg WW model. yours may have been changed at some point. I would check the carb/manifold gasket. sometimes they leak and cause the idle to jump. Try spraying starter fluid at the base of the carb. if the idle increase while you do this, thats your problem. if not, may be the carb. i've switched two 305 engines to the holley 4412 (500cfm) and i aint complaining. the differance is undeniable. hope this helps. good luck...oh yeah, pics are a must. well not really, but surely appreciated.

[Frizzle Fry]

I'm no expert but have read a bit about the big block v6 series. Wasn't the 305 a single barrel carb? I've read about guys swapping on 351 manifolds to go to a two barrel.
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[wc63]

i think the 2 barrel started in or after 62. i have a 63 and a 66 and they both have the 2 barrel carb. ive also heard of the 351 manifold swap but im not sure if it makes a drastic difference, since the ports on the heads are still for the 305.

[markeb01]

Originally Posted by kf4jfk

First off I want to say I have fell in love with this forum. There is so much valuable information that I find myself losing sleep, but i'm not complaining. I have been searching for my next toy for some time and I finally found it. Its a 1964 GMC Fleetside Longbed w/ 305ci V6 and a 4-speed.

I don’t have the answers to your questions, but welcome to the forum!

Originally Posted by wc63

ive also heard of the 351 manifold swap but im not sure if it makes a drastic difference, since the ports on the heads are still for the 305.

I think the main improvement in the swap is efficiency and ease of tuning. The newer carb is a much more modern design and easily adjusted, while not much can be done with the originals other than a stock rebuild.

[kf4jfk]

I appreciate the heads up. I will do sme more investigating and let you guys know what is going on. I should have thought about the gasket leaking since I've been a motorcycle mechanic for over 15 years.

Will try to get some pics soon. Thanks guys!
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['63GENIII]

Welcome from Nor Cal. You are in the right place for your info. I'd ask for pics too but I can never get them to work myself.