tranny recommendations - The 1947 - Present Chevrolet & GMC Truck Message Board Network

cojnit · 07-31-2003, 07:01 PM

I got my 350 engine, and now I need a trans. What do you all recommend for a low hump suburban. It originally had a 3 on the tree. Would like to be able to go into the 90-100 mph comfortably, and still have some nice giddy-up off of the line.

Also is it likely that I will have to cut the floor to put one of these in? if so how bad????

crazy longhorn · 07-31-2003, 07:07 PM

It sounds like you need an overdrive trans......are you looking to keep a stick , or go auto trans?

cojnit · 07-31-2003, 07:09 PM

think I want to go to an auto.

but curious on the options for both.

lukecp · 07-31-2003, 10:19 PM

If you want to cruise 90 and still have good low-end acceleration, a 700R4 or 200R4 automatic would be the way to go for an auto tranny. The 700R4 has a low 1st gear (3.06:1 compared to 2.52:1 on a TH350), and has a .70:1 ratio overdrive, which will allow you to travel 30% faster at the same RPM you are turning in high gear right now.

The 200R4 has seveal advantages over the 700R4, but can be more difficult to find and some say it is a waker tranny. The 200R4 has a higher 1st gear than the 700R4; it is 2.75:1. That isn't really a bad thing though. The RPM drop off between 1st and 2nd gears on a 700R4 is pretty bad, about 50%. So if you are turning 5,000rpm in 1st gear, when you hit 2nd, your rpm will drop to 2500, and uless your motor has alot of low-end power, it may slow you down a little bit. The 200R4 has about a 45% rpm drop off, so it isn't quite as bad.

I would call a local tranny shop, and ask for a price on a rebuilt unit for either the 200R4 or 700R4. There is a post on converting to a 700R4 on the FAQ board.

Also, your floor won't have to be cut with either tranny.

07-31-2003, 07:01 PM	#1
cojnit Nothing clever Join Date: Jun 2003 Location: Kailua HI Posts: 828	tranny recommendations I got my 350 engine, and now I need a trans. What do you all recommend for a low hump suburban. It originally had a 3 on the tree. Would like to be able to go into the 90-100 mph comfortably, and still have some nice giddy-up off of the line. Also is it likely that I will have to cut the floor to put one of these in? if so how bad???? __________________ Got "the Midas Touch!"

07-31-2003, 07:07 PM	#2
crazy longhorn Fabricate till you "puke" Join Date: Jun 2002 Location: Ill Posts: 9,402	It sounds like you need an overdrive trans......are you looking to keep a stick , or go auto trans? __________________ 69 longhorn,4" chop,3/5 drop, 1/2 ton suspension/disc brakes,1 1/2" body drop,steel tilt clip, 5.3/Edelbrock rpm intake/600 carb, Hooker streetrod shorties,2 1/2" exhaust/ H pipe/50's Flows , 6 spd Richmond trans,12 bolt/ 3.40 gears....

07-31-2003, 07:09 PM	#3
cojnit Nothing clever Join Date: Jun 2003 Location: Kailua HI Posts: 828	trans think I want to go to an auto. but curious on the options for both. __________________ Got "the Midas Touch!"

07-31-2003, 10:19 PM	#4
lukecp Formerly yellow72custom Join Date: May 2001 Location: Austin, TX Posts: 7,531	If you want to cruise 90 and still have good low-end acceleration, a 700R4 or 200R4 automatic would be the way to go for an auto tranny. The 700R4 has a low 1st gear (3.06:1 compared to 2.52:1 on a TH350), and has a .70:1 ratio overdrive, which will allow you to travel 30% faster at the same RPM you are turning in high gear right now. The 200R4 has seveal advantages over the 700R4, but can be more difficult to find and some say it is a waker tranny. The 200R4 has a higher 1st gear than the 700R4; it is 2.75:1. That isn't really a bad thing though. The RPM drop off between 1st and 2nd gears on a 700R4 is pretty bad, about 50%. So if you are turning 5,000rpm in 1st gear, when you hit 2nd, your rpm will drop to 2500, and uless your motor has alot of low-end power, it may slow you down a little bit. The 200R4 has about a 45% rpm drop off, so it isn't quite as bad. I would call a local tranny shop, and ask for a price on a rebuilt unit for either the 200R4 or 700R4. There is a post on converting to a 700R4 on the FAQ board. Also, your floor won't have to be cut with either tranny. __________________ '72 Chevy C10 Mild 350/TH350/3.07. Ochre/White. Old high school ride. '70 GMC C2500 '62 327 4bbl/SM465/4.56-geared Dana 60. White/White. Project or parts truck. '97 Saturn SL DD. 1.9/5-speed. 40+ highway mpg



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