What 4 speed do I have? 1969 c20 - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Ehud · 12-22-2018, 09:40 AM

I am doing a ls swap and thinking about using this transmission. Which tranny do I have? Any input would help. My engine is all stock. And looking to get it on the road. I have this c20 4 speed that I belive to be good.
Thanks.

57taskforce · 12-22-2018, 02:54 PM

Looks like an sm465 to me.

B. W. · 12-22-2018, 03:52 PM

Ditto, 465

Ehud · 12-22-2018, 07:41 PM

Thanks folks

Mike C · 12-22-2018, 09:14 PM

How long has it been sitting like that? The shift tower is open to any rain and snow that chooses to fall on it. Even odds are it will be full of water.

Ehud · 12-23-2018, 10:23 AM

It’s all good. No moisture. From what I have gathered this transmission has a extremely low first gear. Does this sound correct?

toms68cst · 12-23-2018, 10:24 AM

Quote:

Originally Posted by Ehud

It’s all good. No moisture. From what I have gathered this transmission has a extremely low first gear. Does this sound correct?

YUP! AKA Granny gear.

Mike C · 12-23-2018, 08:46 PM

What are your goals for the truck? How are you configuring your swap motor? The SM465 is an awesome trans for a working truck. The deep first gear makes offroading and towing possible with moderate gear ratios.

But if you are looking to build a hotrod type street machine, the SM465 is the wrong transmission.

I ran a big cammed 327 in my Jimmy and the torque characteristics were completely wrong for the gear split on the 465. With the 210@.050 cam that is in it now, it works great.

**jocko** · 12-24-2018, 10:23 AM

Granny is 6.55:1. You won't use it unless farming or rock crawling. And that's ok, just something to be aware of.

Quikshft · 12-24-2018, 01:40 PM

Quote:

Originally Posted by Ehud

It’s all good. No moisture. From what I have gathered this transmission has a extremely low first gear. Does this sound correct?

My 4x4 has 3.07 differential gears and 33 inch tires and 1st gear even with that set up is pretty much un-needed on the street. You'll be left with essentially a three-speed. As somebody else mentioned it is a fine transmission for a working truck, I tow a 4,500 pound travel trailer and will use 1st to get things moving.

12-22-2018, 09:40 AM	#1
Ehud Registered User Join Date: May 2015 Location: E-Town Posts: 44	What 4 speed do I have? 1969 c20 I am doing a ls swap and thinking about using this transmission. Which tranny do I have? Any input would help. My engine is all stock. And looking to get it on the road. I have this c20 4 speed that I belive to be good. Thanks. Attached Images

12-22-2018, 02:54 PM	#2
57taskforce All about them K’s Join Date: Jun 2014 Location: Land of Entrapment Posts: 6,504	Re: What 4 speed do I have? 1969 c20 Looks like an sm465 to me. __________________ Tyler '57 3100 http://67-72chevytrucks.com/vboard/s...d.php?t=813888 '72 K20 Cheyenne: 5” lift, 35’s, front dana 60 blah blah blah… http://67-72chevytrucks.com/vboard/s...d.php?t=662879 ‘69 K10 SWB: 4” lift 33”s… in a million pieces http://67-72chevytrucks.com/vboard/s...d.php?t=805206 '98 Silverado LT K2500HD ECLB Vortec 454/4l80E: 6" lift 35x12.5x20’s

12-22-2018, 03:52 PM	#3
B. W. Registered User Join Date: Nov 2014 Location: Bigfork, Montana Posts: 1,137	Re: What 4 speed do I have? 1969 c20 Ditto, 465

12-22-2018, 07:41 PM	#4
Ehud Registered User Join Date: May 2015 Location: E-Town Posts: 44	Re: What 4 speed do I have? 1969 c20 Thanks folks

12-22-2018, 09:14 PM	#5
Mike C Registered User Join Date: Dec 1999 Location: Austin, TX, USA Posts: 7,728	Re: What 4 speed do I have? 1969 c20 How long has it been sitting like that? The shift tower is open to any rain and snow that chooses to fall on it. Even odds are it will be full of water. __________________ 44 Willys MB 52 M38A1 64 Corvette Coupe 68 Camaro 'vert LT1 & TH700 69 Z/28 355 12.6's @110 69 Chevy Short Step 4 1/2"/7" drop 72 Jimmy 4WD 4spd 4" & 35's 02 GMC 2500HD 4x4 Duramax

12-23-2018, 10:23 AM	#6
Ehud Registered User Join Date: May 2015 Location: E-Town Posts: 44	Re: What 4 speed do I have? 1969 c20 It’s all good. No moisture. From what I have gathered this transmission has a extremely low first gear. Does this sound correct?

12-23-2018, 08:46 PM	#8
Mike C Registered User Join Date: Dec 1999 Location: Austin, TX, USA Posts: 7,728	Re: What 4 speed do I have? 1969 c20 What are your goals for the truck? How are you configuring your swap motor? The SM465 is an awesome trans for a working truck. The deep first gear makes offroading and towing possible with moderate gear ratios. But if you are looking to build a hotrod type street machine, the SM465 is the wrong transmission. I ran a big cammed 327 in my Jimmy and the torque characteristics were completely wrong for the gear split on the 465. With the 210@.050 cam that is in it now, it works great. __________________ 44 Willys MB 52 M38A1 64 Corvette Coupe 68 Camaro 'vert LT1 & TH700 69 Z/28 355 12.6's @110 69 Chevy Short Step 4 1/2"/7" drop 72 Jimmy 4WD 4spd 4" & 35's 02 GMC 2500HD 4x4 Duramax

12-24-2018, 10:23 AM	#9
jocko Senior Member Join Date: Oct 2009 Location: Godley, TX Posts: 17,975	Re: What 4 speed do I have? 1969 c20 Granny is 6.55:1. You won't use it unless farming or rock crawling. And that's ok, just something to be aware of.



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