purchasing a 1965 gmc 305v6 truck

[Ianmattchevy]

Hey guys and gals i am tempted to purchase a 1965GMC 305 v6 ( not an inline ) it has 3 on the tree manual all original with 90k miles. I went and checked it out and it starts and idles beautifully and not drips, not much rust at all. Looks like the tires have a bit of cracking so i am not so sure how fast i can go and still be safe. My question is how are the trannys on these things and also what is the gearing...will it go highway speeds? It has the original air filter ( that takes oil? ) ....what would be one of the first things you would upgrade on this truck to give it better gas mileage and run better.. I am thinking carb ( whats the best kind ), plugs/wires, air filter unit, syn oil change, dist cap....what else? any comments would greatly be appreciated...I am VERY excited to own such a cool classic but I want it also to be a almost everyday driver and be able to hit the freeway here n Cali. I live in woodland hills and can anyone can recommend some shops in this area that specialize in older trucks and cars? Thanks so much.

[slorio]

Take a visit over here and your questions will be answered:

6066gmcguy.org

Regards,
Steve
New Orleans

[newbe351]

Steve beat me to it. These guys can help with most anything GMC V6 related....


http://www.6066gmcguy.org/performance.htm

[duallyjams]

lets see some pics.

[Ianmattchevy]

Here are the pics. Going tomorrow to look at her and I do believe I will be bringing her home. Hey would you guys know what gears are in the rear end on this truck? I am wonderig if she will be able to reach highway speeds with no problems. They didnt put 4:11 or anything that high in the 305 v6s did they? Also I was reading about the holley 500 carb. That might be the very first thing that I do.

[C10 - C90 Bill]

Nice looking truck. If it has the standard, original rear gears they will be kind of low. It should do OK around 55 or 60 on the Hi-way. Not sure what kind of speed limits you have out there.

I was always satisfied with the stock Stromberg Carb. My '66 GMC 305 would get 15 1/2 miles per gallon on the Hi-way after a "super tune" just using stock Delco and AC parts. Although I have switched to Borg Warner Points in recent years.

If you decide to change the rear gears, remember it will mean starting off in 1st will be more of a strain. I would suggest to keep it original if you can keep it under 60 most of the time. You can change the ratio a little by putting extra large tires on the rear. My '72 C-10 had more of a problem with high revs on the Hi-way than my '66 GMC did and I put on a set of 265/75R/15's on it and it was enough to make a difference, plus I like the look. I'm running 235's in the front.

Keep us posted.

Bill

[Ianmattchevy]

Originally Posted by C10 - C90 Bill

Nice looking truck. If it has the standard, original rear gears they will be kind of low. It should do OK around 55 or 60 on the Hi-way. Not sure what kind of speed limits you have out there.

I was always satisfied with the stock Stromberg Carb. My '66 GMC 305 would get 15 1/2 miles per gallon on the Hi-way after a "super tune" just using stock Delco and AC parts. Although I have switched to Borg Warner Points in recent years.

If you decide to change the rear gears, remember it will mean starting off in 1st will be more of a strain. I would suggest to keep it original if you can keep it under 60 most of the time. You can change the ratio a little by putting extra large tires on the rear. My '72 C-10 had more of a problem with high revs on the Hi-way than my '66 GMC did and I put on a set of 265/75R/15's on it and it was enough to make a difference, plus I like the look. I'm running 235's in the front.

Keep us posted.

Bill

Thanks Bill. I used to have a 72 chevy g20 van that had stock 4:11. I couldn't go over 50 mph. I ended up doing a direct swap of the rear end from a 1993 g20 with 3.5 gears and also added taller tires and it was just like putting in an over drive. I was smooth at 75. I havnt gotten the truck on the hwy yet but after tomorrow I will kow. I'll update you. thanks

[padresag]

http://www.6066gmcguy.org/performance.htm
ron

[duallyjams]

I have the 500 carb on mine , it's cold nature but runs really good after it's warmed up.The GMC V6 is a low rpm engine , a lot of low end torque. I don't drive much over 50mph. I put the 63 factory plaid valve covers and a 67 air cleaner.

[Ianmattchevy]

COOL PLAID COVERS, where can one find some of those? also on my 65 305 what else can I upgrade? What would be a relly good air cleaner to add with the holley 500?

[gimmy 64]

my 64 gmc has 3:54 gears in the stck dana 44 rear end. i have a 350 mtr and it would sound like reving pretty high at 65. i went with overdrive tranny. if you don't do much freeway driving you will be fine.

[factorystock]

Clean truck. Looks like a 3/4 ton 1500 series to me. Don't believe me, just check your vin on the door pilar. Should say 1502.... This truck looks exactly how most mid 60's 3/4 tons looked like before a wheel change. Your truck still has the 15" 2 piece rims. Most 64-66 V6 3/4 tons will have the Dana 60 with 4.10 ratio. A Dana 60 axle with 3.54 ratio can be swapped from a 68 thru 72 GMC 3/4 ton with leaf springs also.

[C10 - C90 Bill]

Originally Posted by factorystock

Looks like a 3/4 ton 1500 series to me.

I believe you're right.

I was more convinced when I took a closer look at the Spare Wheel in the truck bed.

To the original poster: If true, that will change what I have stated about your Rear Gears. The 3/4 Ton should have even lower gears.

Pop off the Hub Caps and post another picture, as well as checking on the VIN as mentioned.

Bill

[hemifalcon]

I had a 4x4 '64 GMC 8-lug truck with the 351E (and "cool" plaid valve covers).. It had tall 16" tires on the corners and at 55-60mph--it was screaming--plus I was getting 8-10mpg.. Don't count on going fast in the truck.. It was built for work. And--the GMC V6's run like diesels, meaning they operate at low RPM's to do all their work for ya..
Have fun with it..