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73-87 Chevy _ GMC Trucks => Performance => Topic started by: Nospark on December 22, 2010, 10:29:55 pm

Title: how much hp/tq will a SM456 hold?
Post by: Nospark on December 22, 2010, 10:29:55 pm

like the title says how much HP/TQ will a SM456 hold.  If so what modifications need to be done to it to make it hold?  input, output, mainshaft ect... anybody have any experience with them.   Thanks for the help

Title: Re: how much hp/tq will a SM456 hold?
Post by: Grim 82 on December 23, 2010, 09:03:48 am

In my experience it's pretty tough to break a 465. How much hp/tq is your motor putting out?

Title: Re: how much hp/tq will a SM456 hold?
Post by: 77c10diesel on December 23, 2010, 09:39:58 am

I have never heard of a SM465 breaking, most of the time they break other stuff like the u-joints, axles, drive shaft, etc.
I say just rebuild it with quality parts and go. Worry about the other parts more. You will find the weak link and I doubt the 465 will be it.

Title: Re: how much hp/tq will a SM456 hold?
Post by: Nospark on December 23, 2010, 11:47:54 am

in the process of building a 598 for it shooting for around 7-750hp.   I am coming from performance diesels where you could snap a stock input/output shaft like a toothpick.  I was thinking if the Muncie wouldnt hold up to swap in a NV4500 with billet shafts. 

Title: Re: how much hp/tq will a SM456 hold?
Post by: malibu795 on January 02, 2011, 09:16:31 am

Quote from: Nospark on December 23, 2010, 11:47:54 am

in the process of building a 598 for it shooting for around 7-750hp.   I am coming from performance diesels where you could snap a stock input/output shaft like a toothpick.  I was thinking if the Muncie wouldnt hold up to swap in a NV4500 with billet shafts. 

go look at the stock street and supper street gass class.. and thats what they are running is a 465 and 1000hp

Title: Re: how much hp/tq will a SM456 hold?
Post by: Edahall on January 02, 2011, 07:28:41 pm

I've heard that the weak link on the SM465 is the input shaft, so you might want to upgrade it to a larger diameter shaft.

Title: Re: how much hp/tq will a SM456 hold?
Post by: Irish_Alley on January 03, 2011, 05:36:10 am

There are a couple different input shafts 10 and 32. 10 being weaker not much I haven’t had a problem with mine

Title: Re: how much hp/tq will a SM456 hold?
Post by: Nospark on January 03, 2011, 07:01:54 am

ok thanks guys I will be looking for some upgraded internals if you think it will hold.

Title: Re: how much hp/tq will a SM456 hold?
Post by: Irish_Alley on January 03, 2011, 10:46:30 am

I'm running 38's on mine with no problem