replacing a th400 with a 700r4 - The 1947 - Present Chevrolet & GMC Truck Message Board Network

into69z · 06-17-2007, 02:03 PM

Hey everyone-I'm in the process of installing a 454 in a 69 c-20 long bed. I have a turbo 400 that needs a rebuild, but I'm thinking of changing to a 700r4. What do I need to do like with the shifter? the cross member? drive shaft? it seems to be an easy swap but before i commit to the new trans i would sure like anyone's input-oh-the motor is about 450hp and I would like to pull a trailer thanks steve

**kwmech** · 06-17-2007, 08:07 PM

Lets see, 454---built to 450hp---, full size 3/4 ton truck, towing involved------700r4. Not gonna work for any amount of time. Keep the 400 and install a gear vendor if you want overdrive and want to get back home.

06-17-2007, 02:03 PM	#1
into69z "brand new second-hand" Join Date: Feb 2007 Location: White House, Tennessee Posts: 526	replacing a th400 with a 700r4 Hey everyone-I'm in the process of installing a 454 in a 69 c-20 long bed. I have a turbo 400 that needs a rebuild, but I'm thinking of changing to a 700r4. What do I need to do like with the shifter? the cross member? drive shaft? it seems to be an easy swap but before i commit to the new trans i would sure like anyone's input-oh-the motor is about 450hp and I would like to pull a trailer thanks steve

06-17-2007, 08:07 PM	#2
kwmech Senior Member Join Date: Mar 2003 Location: Colfax-California Posts: 8,398	Re: replacing a th400 with a 700r4 Lets see, 454---built to 450hp---, full size 3/4 ton truck, towing involved------700r4. Not gonna work for any amount of time. Keep the 400 and install a gear vendor if you want overdrive and want to get back home.



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