465 to TH350

GubNi

GubNi

8 lug disc brakes?
Joined
Mar 20, 2005
Location
Jonesborough, TN
What all is involved to convert a 465 to TH350?

I have a 350 motor with 465 and NP205. I want to try to get everything ready so I can do this project in a day. I have heard that my 205 will be 10 spline or 32 spline and if 32 spline it will not work. Is the TH350 version 10 spline?

I have a core TH350 transmission. My radiator is prepped for auto trans.

I need:

flex plate - (what about balance? How do I tell which one I need?)
rebuild TH350 - I have someone to do that
rebuild torque converter or buy one with higher stall
metal lines for trans fluid to radiator (have some, but may not be the right ones)
dip stick
350 to 205 adaptor
possibly 205
trans fluid (how much?)
shifter and cable

Have I left anything out? Any suggestions on what to get or where is appreciated.
 
TH350 trans should be 27 spline. The SM465 came in two versions the short 10 spline or long 32 spline. You will need to find a 27 spline input for your 205 or a 205 from behind a TH350.
 
I was wondering how long it would take for you to do this.:driver:

Use an aftermarket cooler. The one in the rad won't cool as much.

Also I don't know if the starters are different???
 
kickdown cable from your throttle body, don't forget that and the vaccum line for the modulator

factory dipstick tube is a push in type, if you go with aftermarket like Lokar, you'll have to drop the pan as it has a jam nut on the inside.

coolant lines are easy to make work with rubber line if need be.
 
chevy has 2 different types of np205 bolt patterns peanut style or circle style. you need need the automatic driveshafts and cross member as well good luck. its a strong trans if its built rite. it'll take 7 quarts with the stock pan
 
there are three different flexplates a 150 something tooth,a 160 something tooth,and latemodel with a different size pilot hole.
the th350 is a 27 spline you are gonna have to change the input shaft on the np205, the sm465 is gonna be a 10 or 30 something spline neither in you case is gonna work.
your also gonna need a th350 to np205 adapter .
 
So on the flex plate I don't have to worry about it being balanced to the year of the motor? I have very little experience with chevy's and I know Fords do.
 
does it have a one piece rear main seal there will be a aluminum piece bolted to the back of the engine if it does and what side is the dip stick on.
do the valve covers bolt on around the outside edge or thru the center of the cover.
and the two center bolts on the intake on both sides are they at a different angle from the rest meaning standing up straighter
oh and the starters are different the auto bolts to the block ,the standard (sm465)bolts to the bell housing the won't enterchange.
you could get the id # off of the back pass side of the engine where the trans bolts up can usually be seen without to much trouble.
 
does it have a one piece rear main seal --IDK

there will be a aluminum piece bolted to the back of the engine if it does -- I didn't see any aluminum. Would it be on top?

and what side is the dip stick on. -- driver side


do the valve covers bolt on around the outside edge or thru the center of the cover. -- each valvle cover has 4 bolts around the edge - (also it has serpentine belt - but that may have been added)

and the two center bolts on the intake on both sides are they at a different angle from the rest meaning standing up straighter -- They are the same angle as the other intake bolts

oh and the starters are different the auto bolts to the block ,the standard (sm465)bolts to the bell housing the won't enterchange. -- darn


you could get the id # off of the back pass side of the engine where the trans bolts up can usually be seen without to much trouble -- 3970010
 
the motor you have was made from 69 to 79,2 piece rear main seal.
you'll need a 168 tooth flywheel,new starter,trans cooler shifter,trans fluid,vacum line for modulator,kickdown cable, it can be plugged with a freeze plug (i would do this)you dont need this.
then you'll need the correct input shaft for the np205 and adapter.
sorry it took so long to get back i was hungry ha ha.
 
On later model 32 spline SM465 non hydraulic bellhousings the starter bolts to the engine not the bellhousing. I would imagine all non hydraulic bellhousings are this way. You need to figure out if you have a 168 or 153 tooth starter so you get the right flex plate (if by chance you have a mini/gear reduction starter most are universal to the 153/168). A way tell whether yours is 153 or 168 is if you have a 11" or 12" clutch.
 
the sm465 i've got laying in the garage floor is a non hydo bell housing and the starter bolts to the bell housing.
didn't know the hydro version was different learn something new everyday.
your right on the clutch dia it's possible for it to be a 153 tooth?.
 
I looked and my starter bolts to the engine, so I am good there. I won't know the diameter of the clutch until I take it apart.
 
keep all the old parts together, you shouldn't have any problem selling the 465/205 set up. you could probably find more than one to trade out their 350/205 set up for your 465/205
 
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