77 C30 crew Dually trans swap questions - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Mr. M3 · 04-03-2018, 10:17 PM

Currently the truck has a 454 paired to a TH350, my main question is what are your thoughts on putting a 700R4 behind the 454? Keeping in mind this is by no means a speed application, more for heavy loads and towing. The second question being more towards the drive shaft length, will I need to chop the shaft down? I will need a new yoke for sure if I am understanding it correctly (27 teeth vs 30 on the spline).
Thanks in advance for any input!

sweetk30 · 04-03-2018, 10:49 PM

700r4 + 454 + heavy towing loads = DEATH FAST

and its 27 spline or 32 spline on the outputs for gm of our vintage .

if you want beefy its th400 or 4l80-e . and the 4l80-e needs a controler to run it . look these guys up . www.usshift.com great price point and tons of softwear options to play with .

bilfman · 04-04-2018, 12:49 AM

4L80e is the way to go, it’s basically a th400 with overdrive. The electronics are easy with an aftermarket controller. I have a build here in the forums.

04-03-2018, 10:17 PM	#1
Mr. M3 Registered User Join Date: Feb 2018 Location: Arkansas City, Kansas Posts: 14	77 C30 crew Dually trans swap questions Currently the truck has a 454 paired to a TH350, my main question is what are your thoughts on putting a 700R4 behind the 454? Keeping in mind this is by no means a speed application, more for heavy loads and towing. The second question being more towards the drive shaft length, will I need to chop the shaft down? I will need a new yoke for sure if I am understanding it correctly (27 teeth vs 30 on the spline). Thanks in advance for any input! __________________ 1988 Suburban V10 350 TBI 1969 C10 Stepside inline 6 250 (new project) 1977 C30 3+3 Camper special 454

04-03-2018, 10:49 PM	#2
sweetk30 Registered User Join Date: May 2012 Location: horseheads,ny rust belt Posts: 2,794	Re: 77 C30 crew Dually trans swap questions 700r4 + 454 + heavy towing loads = DEATH FAST and its 27 spline or 32 spline on the outputs for gm of our vintage . if you want beefy its th400 or 4l80-e . and the 4l80-e needs a controler to run it . look these guys up . www.usshift.com great price point and tons of softwear options to play with . __________________ 77-k30lb BIG truck build . 87-k30lb budget beater build . 85-k30lb the plow machine build . 85-c10sb summer fun toy . ----------------------------- HOLLEY SNIPER efi = worst case of p.i.t.a i ever had . EDELBROCK pro flo 4 = best deal going so far . love my setup works great.

04-04-2018, 12:49 AM	#3
bilfman Registered User Join Date: Dec 2011 Location: Regina, SK, Canada Posts: 622	Re: 77 C30 crew Dually trans swap questions 4L80e is the way to go, it’s basically a th400 with overdrive. The electronics are easy with an aftermarket controller. I have a build here in the forums. __________________ 1979 Chevy Dually Crew 4X4 454, D60 Tru-trac, D70 Detroit Locker, 3.73, 4L80E/NP205 1971 GMC 3/4 Ton 4X4



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