[chewychevy67]

Originally Posted by 72Cheyenne454

No problem... I'm happy to answer your questions.

I've never experienced any lugging or loss of power. Maybe with a manual trans it might be an issue at low rpm, but with an automatic the converter provides the cushion/slippage to just pull away with no issues. In fact, I can shift my GV into 3rd over as soon as the trans shifts into 3rd and just pull away. I can do the same in second gear as well. Again, the converter helps to make this possible. Think of it as just running a taller rear gear - 2.73, 2.91.

As for rpm, my factory tach does not read correctly, so I don't have any idea what the rpm's are at a specific speed. However, I did punch the numbers in to an online rpm calculator... 3.42, with 28" tire at 47mph is almost 2,000rpm.

For my truck, in 3rd gear overdrive, with my 3.42 gear is the same as having a 2.67 rear gear with no OD.

My 3.42/28" tire combo is nearly identical in overall gear ratio compared to your 3.54/29" tire set up


I mentioned my dads 70 K10 in a post above. Not ideal, but he's currently running a 3.08 gear with a 30" tire and he uses his GV whenever he's on the freeway. He runs around 1,900 rpm at 70. In OD, his 3.08 is the same as running a 2.40 rear gear with no OD.

That's what I was thinking but it's good to hear from someone who has one with a set up similar to mine. I appreciate the information. Rod.