Anybody ever installed a newer transmission on an older engine.

Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.

Frankinmetz

Member
Joined
May 5, 2021
Posts
34
Reaction score
30
Location
Indiana
First Name
Nick
Truck Year
1981
Truck Model
1500
Engine Size
305
Has anyone ever installed a 5 or 6 speed to an old carb. Chevy 350 big block?

Sent from my LM-G710VM using Tapatalk
 

Camar068

Supporting Member
Supporting Member
Joined
Feb 5, 2014
Posts
4,293
Reaction score
3,339
Location
Kentucky
First Name
David
Truck Year
1986
Truck Model
K10/LM7 5.3/4L60e/np208/3.73/32"
Engine Size
10 yrs Air Force
I'd like to find a 350 diesel and be able to AFFORD to convert to gas and de-stroke it :)
 
Last edited:

jjester6000

Full Access Member
Joined
Aug 24, 2019
Posts
882
Reaction score
2,459
Location
Illinois
First Name
Jack
Truck Year
1974
Truck Model
C1500
Engine Size
250
Has anyone ever installed a 5 or 6 speed to an old carb. Chevy 350 big block?

Sent from my LM-G710VM using Tapatalk
The bellhousing pattern for most GM engines has been the same since 1955, so swapping in a newer transmission should be no problem.

If I were you, I'd pick up either an NV3500 5 speed (easier to find, and actually came in trucks) or a T56 6 speed (Expensive, and never actually put into trucks, but it has one extra gear)

If you are going for the Nv3500 route, I'd find a later, 88-98 GMT400 parts truck with a 5 speed and swap all the parts over (Clutch pedal, lines, Exc.)
 

Frankinmetz

Member
Joined
May 5, 2021
Posts
34
Reaction score
30
Location
Indiana
First Name
Nick
Truck Year
1981
Truck Model
1500
Engine Size
305
The bellhousing pattern for most GM engines has been the same since 1955, so swapping in a newer transmission should be no problem.

If I were you, I'd pick up either an NV3500 5 speed (easier to find, and actually came in trucks) or a T56 6 speed (Expensive, and never actually put into trucks, but it has one extra gear)

If you are going for the Nv3500 route, I'd find a later, 88-98 GMT400 parts truck with a 5 speed and swap all the parts over (Clutch pedal, lines, Exc.)
That was the exact answer I was looking for!! [emoji120][emoji120][emoji120] Thank you.

Sent from my LM-G710VM using Tapatalk
 

Frankenchevy

Proverbs 16:18
Joined
Jan 3, 2018
Posts
6,082
Reaction score
7,756
Location
USA
First Name
Jeremy
Truck Year
Square
Truck Model
CUCV
Engine Size
Small
I’m not sure that you can swap over gmt400 stuff directly. If you want a direct swap hydro clutch pedal, you are better off finding a hydro pedal assembly from an 85-87. It’s $$$, but everything else is going to require some level of fabrication.

I believe the gmt400 stuff is also passenger side throw out and uses a hydro TO vs a slave cylinder. That’s usable, but you’ll need longer hydro lines if I recall correctly. In other words, I think the trans itself, excluding the bell housing, is the only direct swap. The bell housing swaps, but again the clutch stuff is on the passenger side.
 

Ricko1966

Full Access Member
Joined
Apr 11, 2017
Posts
5,449
Reaction score
8,686
Location
kansas
First Name
Rick
Truck Year
1975
Truck Model
c20
Engine Size
350
Yes we have installed newer transmissions on older engines, we've installed older transmissions on newer engines, we've even installed engines and transmissions from different makes. We own Chevys damnit !!
 

bucket

Super Moderator
Staff member
Super Moderator
Joined
Aug 3, 2010
Posts
30,439
Reaction score
28,345
Location
Usually not in Ohio
First Name
Andy
Truck Year
'77, '78, '79, '84, '88
Truck Model
K5 thru K30
Engine Size
350-454
Yes we have installed newer transmissions on older engines, we've installed older transmissions on newer engines, we've even installed engines and transmissions from different makes. We own Chevys damnit !!

Yep! I'm sure there's people running 4L60e's behind their 283's and there's people running a Powerglide behind their LS engine. There's even a member here that's running a modern Jeep 5-speed behind their 250 inline six.
 

JustJohn

Junior Member
Joined
Feb 22, 2016
Posts
26
Reaction score
9
Location
Greenville
First Name
John
Truck Year
1985
Truck Model
C10
Engine Size
350
Have a TKO500 on my 454 in the Impala, bolt patterns are the same for all of them (SBS, BBC). I had the OE clutch linkage. If that's not available, lots of kits to add a hydraulic clutch are available.
 

nujac

Junior Member
Joined
Sep 29, 2014
Posts
16
Reaction score
5
Location
texas hill country
First Name
bruce
Truck Year
1982
Truck Model
k20
Engine Size
350
I swapped out a turbo 350 with a NV4500 about 10 years ago. I do not know if in 1979 K15 automatic trucks rear ends had a higher ratio than an automatic. Was very pleased with the swap getting another 4 or 5 MPG but the rear end ratio is too high to use 5th gear.
 

Latest posts

Forum statistics

Threads
44,163
Posts
950,653
Members
36,276
Latest member
2manysquares2care
Top