The 1947 - Present Chevrolet & GMC Truck Message Board Network - View Single Post

**WIDESIDE72** · 09-07-2013, 01:46 AM

Any original equipment transmission in 67-72 trucks will be 1:1 in third gear, whether its an 4 spd SM420, 3 spd saginaw, TH400 or TH350. The only way to get your engine spinning slower is to swap to a numerically lower rear gear ratio or swap in an overdrive of some sort; 700r4, 2004r, T56, NV3500/ 4500, gear vendors etc.

09-07-2013, 01:46 AM	#5
WIDESIDE72 Senior Member Join Date: Aug 2008 Location: Cedar Park, Texas Posts: 7,500	Re: Three speed Saginaw top speed ? Any original equipment transmission in 67-72 trucks will be 1:1 in third gear, whether its an 4 spd SM420, 3 spd saginaw, TH400 or TH350. The only way to get your engine spinning slower is to swap to a numerically lower rear gear ratio or swap in an overdrive of some sort; 700r4, 2004r, T56, NV3500/ 4500, gear vendors etc.