1965 gmc best tranny mate to 350
 

I'm getting a 350 motor to drop in my 65 GMC. I've read all the posts and I'm quite confused on which tranny to mate to the 350. I'd like to get a tranny that drops in that would be able to tow a small camper and still have highway driving capability. What is the best tranny to drop in with the least amount of modifications?

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Re: 1965 gmc best tranny mate to 350
 

You didn't mention whether you prefer a manual or automatic transmission. For me the choice would be a 700-R4 auto. Low ratio 1st gear and overdrive too.

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Re: 1965 gmc best tranny mate to 350
 

Auto is my preference. So where can I get all the mod instructions to make the 700-r4 swap? Currently i have a 3 on the tree.

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Re: 1965 gmc best tranny mate to 350
 

Agreed! I have a 350/700R4 combo now.
2200 stall lockup converter with lockup option in every gear

Now, I will admit that the only reason I swapped out the original powerplant was because I could not find parts for it in the early nineties..no oil pressure and was knocking. Small town with one parts store that had no idea about a 305 V6, no internet, and inexperience with 305's led me to swap to a 350/350 combo to get the truck on the road. The 700R4 came years later. About the only thing that was difficult was getting the TV cable adjusted and re-sizing the driveline.

John

Re: 1965 gmc best tranny mate to 350
 

I used a B&M Truck shifter to connect to my 700R4. Since it uses a cable linkage, it made the mod extremely easy. My manual transmission mount was bolted to the frame, so I was able to easily use it for my 700R4 tranny mount. I know some trucks had the transmission mount rivited to the frame rails...more difficult to remove.

Re: 1965 gmc best tranny mate to 350
 

Thanks for the info. I'll start researching the swap.

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Re: 1965 gmc best tranny mate to 350
 

I bought my transmission from Bowtie Overdrives and ordered their TV cable setup as well. What I liked about BO is that they install their transmission into vehicles and take pressure readings before sending the tranny to the customer. This way, when the customer installs the tranny into their vehicle, the pressure readings can be compared. If they are close enough, the warranty starts. If the reading are off, they work with the customer on adjustments (usually the TV cable) in order to get the pressures right. Once the technician is satisfied with the customers readings, the warranty starts. The proper pressures on a 700R4 are critical in order to prevent transmission failure.

John

Re: 1965 gmc best tranny mate to 350
 

Outstanding advice! I'll look em up. Thanks!

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Re: 1965 gmc best tranny mate to 350
 

Tci makes a valve body for the 700r4 that makes the throttle valve cable, controll shift points only, eliminating problems with low line pressure from misadjusted tv cable. You still have to adjust the cable, but only to change shift points. I have this setup in my s-10 with 350 tpi with 700r4. Works great, firms up shifts, acts like a mild shift kit. I believe they call it a constant pressure valve body.

Re: 1965 gmc best tranny mate to 350
 

Thanks. I'll look into that as well! Forgot to mention Im replacing a tired inline 6. Cant find an original v6 305 so im going 350.

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Re: 1965 gmc best tranny mate to 350
 

I'm sure I speak for most of our fellow forum members when I say that I'm glad you're not pulling a V6 to install a Chevy engine. Maybe someone here on the forum who lives not too far from you has a spare V6 they'd part with. Or maybe you can replace that 350 someday with a V6 if you continue looking for one.

Re: 1965 gmc best tranny mate to 350
 

I would prefer the V6. Anybody have one near Milwaukee WI?

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Re: 1965 gmc best tranny mate to 350
 

Try these:

https://minneapolis.craigslist.org/r...054724178.html

https://southbend.craigslist.org/pts/6134716984.html

https://springfieldil.craigslist.org...066797471.html

Re: 1965 gmc best tranny mate to 350
 

That 401M out of the 69 7500 series truck appears to have a 4bbl carb, could it be that rare dealer installed option?:upyes:

Re: 1965 gmc best tranny mate to 350
 

Anybody have an opinion on how the 305 v6 with the 4 speed tranny would do pulling a small camper and would it be screaming at 65 mph?

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Re: 1965 gmc best tranny mate to 350
 

A 305 would have no trouble pulling a small camper. Whether or not it would be "screaming" at 65 would be totally dependent on rear end ratio and tire diameter, both of which can be changed to suit your needs.

Re: 1965 gmc best tranny mate to 350
 

If that IS, that's a stinkin burma rarity!

Re: 1965 gmc best tranny mate to 350
 

The day I ordered my '87 F-150 I test drove a truck with 300-6 and 4 spd overdrive with 3.08 gears. It would run about 45-50 in 1st, but shifting in the O/D 4th stopped any semblance of acceleration. I had driven a '78 F-150 300-6 and NP435 & NP-205 T-case with 3.55 gears for seven years and 95,000 miles. I went with that Exact same drive train with the changes FMC had made like the 8.8" rear axle in place of the 9", and Twin Traction Beam Dana44 in place of the Monobeam Dana 44. With the creeper low gear you could crawl around at an idle easily, trailer, or mud and snow would be no problem. Second gear was normal starting gear good for about 15 mph, 35-40 in 3rd gear and Tach would read about 2600-2700 at 65 mph in 4th, returning about 12-13 mpg. Traction-loc was not available with 3.08 ratio. That would have helped mpg at Interstate speeds at the expense of having to use low gear to crawl around and really slow acceleration in 4th gear. Trailer towing in 4th would have been very small. The '87 EFI engine was rated 145 hp, vs the carb'd engine rating of 120-125hp, I think installing a 5-speed would be the best solution. The over-drive 5-speed for the half ton Ford barely survives running around empty, the ZF used in the bigger trucks is huge!. SON's buddy in high school had about a '92 Work Truck C1500, 4.3L 5-speed, wide ratio. If that could fit the 305 V-6 that would allow towing in most conditions and good cruising at 65+. Just not enough gears in a 4-speed, but many good 5&6 speeds available now.

My current truck I scratched around and figured gearing for months before I finally ordered it. After wearing out two F-150s that had too many low gears and not enough of a high gear I wanted something that would crawl and fly. The 5-speed ZF manual is considered a close ratio but I think it's pretty wide ratio actually. In high side of T-case I can idle at 600 rpm at about 3-4 mph in low gear, and can accelerate up to 2500 rpm in 4th to almost 65 mph and cruise at 67 mph at 2000 rpm in 5th. 3.55 axle gears and 32-33 inch tires. It's a 7.3L PSD, and I averaged about 19 mpg the first 240,000 miles before I semi-retired it to just towing & hauling, no commuting empty to/from work. The drive train would work great with a 401 V-6 providing the motivation.

Re: 1965 gmc best tranny mate to 350
 

I wish I had as many engine sale options here in San Antonio, I would buy them all!

Re: 1965 gmc best tranny mate to 350
 

These are not "in San Antonio", but may be close enough for you:

https://killeen.craigslist.org/pts/6051147007.html

https://dallas.craigslist.org/dal/pts/6133419761.html

https://dallas.craigslist.org/dal/pts/6079064851.html

If not close enough, someone else on the forum may want them.