Transmission Reccomendations for 383 500hp

[Nor_Cal_Crawler]

My 383 is almost finished and will have a little north of 500hp and slightly more torque. I currently have a Getrag 5LM60 or nv3500 5spd and im wondering if i should replace it with something stronger. Currently dont have posi and this is a 4wd application. I had an sm465 in my previous truck (an 89 k1500) and honestly loved it. Thought about going with a 6spd (has option for low 1st) so i would effectively have 5 gears for economy purposes (take what i can get there).

If i am correct then my current tranny has a 10 spline and im worried once i get a little heavy in the foot i might break things. I refuse to own an automatic. Any input is always appreciated.

 

[Jesse_Wenting]

500hp isn't enough to kill most of these transmissions; a 4L60e can handle around 700 ponies. Torque what you need to worry about and if I was making a bit more than 500 ft Lbs I'd be thinking about building up a 4L80e. Hotrod.com did a nice writeup here

 

[DerekTheGreat]

Uhm, OP refuses to own automatic transmissions haha. I support that sentiment. I HATED the SM465 in our C3500, took so long to shift and such long throws- dump truck trans. If you could find a good deal on a NV4500, go for it. If I remember right, '95 or '96 was the first year for the internal slave cylinder. Not sure what year yours is but if you're looking for less pain during the swap you'll want to figure that out and buy a trans accordingly. I'm sure others will provide better info than me.

 

[RichLo]

95 was the first year of the improved gear ratios and the last year of the external slave for the NV4500

 

[Nor_Cal_Crawler]

I did some reading on the 465 and was under the assumption that the 465 designation was essentially the amount of torque the transmission was rated at. I had a 465 in my previous truck that i really liked. I dont mind the long throw but i reallt liked having that low gear. It was sort of like having a double transfer case without the headache. 4 low plus granny gear was great. I suppose i would be open to a 4500 though. Is it possible to have it modified and swap 1st gear for a 6:1 gear? The tr4050 (i think its called) by tremec is a 5spd with low 1st. That would net me one extra gear over the 465 for economy reasons. Also gonna set me back around 3 to 4k wheras I can get a sm465 for around 4 to 700 dollars used. FML the decisions haha. I suppose i can stick with the stock 5spd for a while hell i dunno haha

 

[RichLo]

94 and older NV4500 had the lower granny gear 1st.

 

[Nor_Cal_Crawler]

500hp isn't enough to kill most of these transmissions; a 4L60e can handle around 700 ponies. Torque what you need to worry about and if I was making a bit more than 500 ft Lbs I'd be thinking about building up a 4L80e. Hotrod.com did a nice writeup here

I appreciate the insight, however i wont be using an automatic. I wouldnt call my truck a daily driver. I drive it around town and highway often enough but its kind of a big boy toy. I do a lot of 4 wheeling in the snow here and an automatic just doesnt get the job done. I am pretty much of the mind that a manual transmission is better than an atuomatic for 4x4 in 90 percent of use cases. Having that control over engagement is priceless.

 

[Nor_Cal_Crawler]

94 and older NV4500 had the lower granny gear 1st.

Oh i missed that comment, now im looking into the 4500 for sure.

 

[Sparkysikes]

I disliked my nv4500 for its 2-3 shift. (where 1 was granny) and. My motor was a quick to boost 6.5 turbo diesel. Torque wasnt an issue at low rpm. HP was tho

 

[DerekTheGreat]

'95 and up still have a granny type gear, especially if you've got 3.73's or higher. If you aren't going to drive it on the road, then the advantage of an NV4500 is probably moot. I drove our C3500 everywhere, top speed of 60mph was atrocious as well as the MPG. Held on to the truck for almost two years I think, spent much of that time looking for a '95 NV4500 as Richlo pointed out. Never found one so we sold the truck. I regret selling that thing.