SM465 in 1st gen???

[tuck_the_great]

Anybody have any good links doin the auto to manual swap in a 1st gen Blazer? I finally killed my TH350 and I wanna put a 465 in its place... It's goin behind a 454 and I'd like to keep the 205 in there too... just got a couple questions. Length difference between the two transmissions? and is it enough that d-shaft mods need to be done? and years of truck i need to find so they can donate whatever bits and pieces i need. thats really all i can think of for now.... i'm sure questions about this swap have been done a million times, but i don't have time to search right now... any help is greatly appreciated..

Ty

 

[Ryan B.]

10 spline SM465-NP205, and a TH350-NP205 (27 spline)
are the same dimension wise.
I mention the 10 spline 465 because there is a later style 32 spline version in the 80's trucks that is 32 spline and that version is longer.

I know these are the same length because i originally had a 350, then i swapped to a sm465.
then a couple months ago built up a th350 with a 4000 stall for sand drag racing, used that setup for a weekend, then swapped back to my sm465 for rockcrawling, a few weekends ago.

you can grab the whole setup with the np205 that comes behind the sm465, or you can use your current 205, but you will have to take it apart and replace the 27 spline input gear with a 10 spline input gear.
Don't forget the adapter and coupler sleeve to connect the SM465 to the NP205.

The clutch pedal you can grab out of any 67-72 era truck, and there should be a sleeve/hole right above your brake pedal assembly, just waiting for the clutch pedal to be installed.

i also suggest trying to find a hydraulic clutch setup from a late 80's truck as well. get the bellhousing, slave cylinder, line, and master cylinder.

 

[tuck_the_great]

thanks for the info! would there be any issues as to strength of the 10 spline? its goin behind a 500hp 454... and yeah, I'll admit it. I'm a complete NooB when it comes to this...

 

[fryed_1]

Grab the tranny tunnel housing out of a donor truck as well. Saves a little hassle in cutting your existing one out compared to the $10 or so it will cost you from the average junkyard.

I'm in the middle of the same swap. As far as strength difference, do a search. You'll find pros and cons supporting each.

And seconded on the hydro gear. Your left leg will thank you for it after a few days.

Not sure on the crossmember for the two either. I swapped from a 700r4/241 to a 465/205 and had to swap mine out, but I knew they would be different lengths.

Also I'm running EFI 350 and I had to swap the chip out for one from a similar year manual. It's not "necessary" because it will run with the auto chip in it, but you might throw a light or stall occasionally on rapid decelleration. Don't know if your 454 is EFI or not, but if it is, you might have to do the same.

 

[Moody]

Like Ryan said if you use the 10 spline 465/205 combo it's the exact same length. I just did the same swap in my 70 and everything just bolted in. You won't be able to use the auto crossmember as it sits to low and bolts inside the frame rails. I used the crossmember from the 465/205 combo I got and it came out of a 78. Works just fine, it just bolts right under the frame in the same spot. Try to save your 205 frame bracket to use with the 465. The later years did not come with this and I had to have my transfer case drilled and tapped for 5/8-11 to utilize my old bracket. I'm still working my mechanical clutch linkage, got the pedals, bracket and linkage out of a 69. I'm going to have to improvise as the 70 had a ball stud mounted on the motor to attach your Z bar and my 406 does not have this. I'll probably fab up a bracket. I'm sure a hydro would be slick but I didn't have access to one when I installed the tranny. Good luck!

 

[bp71k5]

You can use hydro with the stock clutch fork. I did. Just use an external slave cylinder since you need a bracket anyway.