72 c10 easy tranny swap

[Johoevasmatrix]

Ok so I have searched the forum a good bit. And I guess I need more info than what I’m finding. Got a sag 3sp. Shifter in the floor. Still mechanical. Looking for the easiest 5 spd tranny to swap on a 307. T5 is tossed out. Was looking at the 4500 or the tremec 600. I’m starting to put more into this than planned like a very project that I or anyone has done. So the 4500 looks like I’ll need to relocate the shifter or go with a hurst shifter conversion? Correct? The tremec 600 will need a new bell housing? Which one is the most straight forward swap? What else would be to do this swap? Did I miss a tranny that would be easier to swap in?

[Alex V.]

If your truck has a rear end ratio on the faster side of the spectrum a 5-speed may be of little benefit...

[Johoevasmatrix]

Originally Posted by Alex V.

If your truck has a rear end ratio on the faster side of the spectrum a 5-speed may be of little benefit...

Was told 3.73 gears in the rear.

[Bigdav160]

Why not a T-5?

Those other transmissions are overkill with a 307

[jocko]

I wouldn't rely on "was told" rear gears when deciding on a trans swap.
What are the details of your truck, besides 307 and 3-spd manual? (year, VIN first 3 characters, C10? C20?)

Better yet, if your truck has a SPID, just post that, it will help us figure all of the above. A 307 in it now may not necessarily mean it was born that way. Do you still have the boss on the steering column for the column shifter?

Is there any annotation on your SPID for a gear ratio (again, or just post it)?
All of the above can only narrow down what it was born with, not necessarily what it has today. It's at least been modified to have a 3-speed floor shifter which was not a factory option, so who knows.

What's the reason you want to switch to a 5-speed? Reduced highway rpm? To Alex's point, if you happen to have a 3.07 rear, for instance, the overdrive ratio won't be such a good thing at higher highway speeds, rpm will be too low.

Bottom line, it's worth doing some of the rear gear checks, either by tire vs d/s rotations vs # wheels turning, etc to ballpark it (several threads on here about that) or, better yet, popping the rear cover (rear end dependent) and counting teeth just to be sure - then you can make a more educated decision on how to achieve your goal.

If you're certain the truck has full original driveline, then we can help you figure out what it came with and you can go from there.

Also keep in mind that the only accurate way to figure out what your rpm at a given speed is on these old truck when you don't know if they've been modified is with a GPS and tach while you're driving it. If changes were indeed made to the rear, then speedo would be completely inaccurate.

FWIW, a T5 is just fine for a 307 engine, unless you plan to do a bunch o burnouts. A Tremec 600 is a bit pricey to be hangin out behind a 307, unless you plan a future engine swap, etc. All comes down to how you're gonna drive it.

[HO455]

How about one of the Ranger hi/low's? Make your 3 speed into a 6 speed.

http://www.advanceadapters.com/categ...lete-units/91/

[volksworld]

not on your list but muncie 4 speed easiest....same length, same spline on both ends, same floorshift hole

[Johoevasmatrix]

Originally Posted by jocko

I wouldn't rely on "was told" rear gears when deciding on a trans swap.
What are the details of your truck, besides 307 and 3-spd manual? (year, VIN first 3 characters, C10? C20?)

Better yet, if your truck has a SPID, just post that, it will help us figure all of the above. A 307 in it now may not necessarily mean it was born that way. Do you still have the boss on the steering column for the column shifter?

Is there any annotation on your SPID for a gear ratio (again, or just post it)?
All of the above can only narrow down what it was born with, not necessarily what it has today. It's at least been modified to have a 3-speed floor shifter which was not a factory option, so who knows.

What's the reason you want to switch to a 5-speed? Reduced highway rpm? To Alex's point, if you happen to have a 3.07 rear, for instance, the overdrive ratio won't be such a good thing at higher highway speeds, rpm will be too low.

Bottom line, it's worth doing some of the rear gear checks, either by tire vs d/s rotations vs # wheels turning, etc to ballpark it (several threads on here about that) or, better yet, popping the rear cover (rear end dependent) and counting teeth just to be sure - then you can make a more educated decision on how to achieve your goal.

If you're certain the truck has full original driveline, then we can help you figure out what it came with and you can go from there.

Also keep in mind that the only accurate way to figure out what your rpm at a given speed is on these old truck when you don't know if they've been modified is with a GPS and tach while you're driving it. If changes were indeed made to the rear, then speedo would be completely inaccurate.

FWIW, a T5 is just fine for a 307 engine, unless you plan to do a bunch o burnouts. A Tremec 600 is a bit pricey to be hangin out behind a 307, unless you plan a future engine swap, etc. All comes down to how you're gonna drive it.

Ok so today I decided to start cleaning Her up a bit. Noticed oil looked like it was coming from both valve cover gaskets. So I gave her a good cleaning and changed oil and valve cover gaskets. The rear end will be next week. So count the teeth on gear and count the rotation compared to the wheel. That will get me my confirmed rear end gear correct? The reason for the change is too high of rpm on highway. The T5 is out because I trashed too many as a kid. I was extremely confident in changing transmission and clutch in s-10........ If I do this swap I’d like to keep the option open to drop a bigger engine in it later with out doing another tranny. Vin number cce142b169 it is a c10 thank you guys for your input.

[HO455]

After removing the cover you count the teeth on the ring gear and the pinon gear then divide them to get the ratio. Many times you can find the numbers stamped on one of the gears. 3:73 should be 41 teeth on the ring and 11 on the pinon. 11/41=3.727272 or 3:73. The stampings may look look like (41*11 or 11-41). Here is a link with common ratios.

http://www.crawlpedia.com/gear_tooth_calculator.htm

[Johoevasmatrix]

So tranny shop here in SC recommended the nv3500. Anyone running one?

[HO455]

Here is a link to Novac's tranny information site. Just click the 5 speed bar. Gives dimensions, ratings, ratios and lots more. Hope this helps.

https://www.novak-adapt.com/knowledg...ssions/manual/