SM 465 to some 5 or 6 speed

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.

tx_truckin

Junior Member
Joined
Sep 5, 2011
Posts
4
Reaction score
0
Location
Fort Worth
First Name
Jason
Truck Year
1983
Truck Model
k10
Engine Size
350
I have a SM 465 in my 1983 Chevy k20 with a 350 and at 60 I'm pushing 3000 RPM's.

Is there a 5 or 6 speed transmission that I can change to that will give me one or two more gears so the rpms will go down and gas mileage will improve.

Specs on truck:

1983 k20
350 4 bolt main
sm465
np205
4.10 rear end
 

GreaseDog

Full Access Member
Joined
Aug 8, 2010
Posts
1,189
Reaction score
31
Location
Elkhart, IN
First Name
Jeremy
Truck Year
1977 K20
Truck Model
1980 K2500
Engine Size
350
nothing that is a direct bolt in... and being a K20, did you put the 205 in it? it didn't come that way from the factory. if its a 208, you may have some luck getting an NV4500 in there, no way i'd go with anything smaller than that.
 

oneluckypops

Full Access Member
Joined
Feb 6, 2011
Posts
2,210
Reaction score
90
Location
Sedalia, Mo.
First Name
Luke
Truck Year
85
Truck Model
K30 SRW
Engine Size
5.7 Fuel injected Vortec/ 4L80E
I dont know what Tire size you are running, but if you go to a taller tire it will ower your RPM'S. Try playing around with different tire sizes on some of the online calculators
 

GreaseDog

Full Access Member
Joined
Aug 8, 2010
Posts
1,189
Reaction score
31
Location
Elkhart, IN
First Name
Jeremy
Truck Year
1977 K20
Truck Model
1980 K2500
Engine Size
350
by my calculations, he needs to put the tires on the truck back on the wife's prius, and put some real tires on the truck... 28" tires on a 4x4? either that, or he doesn't have a tach and is guessing the RPM.
 

Swims350

Full Access Member
Joined
Jul 30, 2010
Posts
4,351
Reaction score
811
Location
Logan WV
First Name
Chris
Truck Year
1983
Truck Model
K10
Engine Size
none
well somebody correct me if I'm wrong but aint 5 and 6 speeds only better then 1:1 when in like 5th only or 6th? meaning anything less then your last gear is equal to having a 4 speed?

I would agree I got 28's on my stock 88 and they are too small I hate it. run some 33's or 35's on it. Cheaper in some ways and easier then a trans swap.
 

crazy4offroad

Equal Opportunity Destroyer
Joined
Jul 30, 2010
Posts
8,468
Reaction score
1,068
Location
West BY-GOD Virginia
First Name
Curt
Truck Year
1979
Truck Model
K-10
Engine Size
350/SM465/NP205
Overdrive (5th gear) on an NV4500 is 0.75:1
 

78shortandwide

Full Access Member
Joined
Aug 9, 2011
Posts
448
Reaction score
19
Location
Denver
First Name
Tom
Truck Year
1973
Truck Model
C10
Engine Size
5.3
I have a SM 465 in my 1983 Chevy k20 with a 350 and at 60 I'm pushing 3000 RPM's.

Is there a 5 or 6 speed transmission that I can change to that will give me one or two more gears so the rpms will go down and gas mileage will improve.

Specs on truck:

1983 k20
350 4 bolt main
sm465
np205
4.10 rear end
I'll trade you axles. I have a Dana 44 and a 12 bolt with 3.73 that might help!
 

Latest posts

Forum statistics

Threads
41,857
Posts
903,628
Members
33,370
Latest member
mitchell1128
Top