The 1947 - Present Chevrolet & GMC Truck Message Board Network - View Single Post - Building a Bulletproof Squarebody Suburban: Community Input Requesting

**buffydores** · 09-07-2018, 08:30 PM

Lol, good point. My concern on fuel economy is more about range not fuel. The Suburban has a 40 gallon tank. Most of the 8.1s seem to get around 10mpg. I'm intrigued by bolting a Allison 1000 6-speed behind it because 1st gear is a little above 3.00 and the second overdrive is in the low .6s. That's attractive for the speeds I'm running on the highway. The 6L90e has a deeper 1st gear for launches, but no other advantage I know. If I could get 12 mpg out of the combo, I'd be rocking.

09-07-2018, 08:30 PM	#7
buffydores Senior Member Join Date: Mar 2016 Location: Longview, TX Posts: 757	Re: Building a Bulletproof Squarebody Suburban: Community Input Requesting Lol, good point. My concern on fuel economy is more about range not fuel. The Suburban has a 40 gallon tank. Most of the 8.1s seem to get around 10mpg. I'm intrigued by bolting a Allison 1000 6-speed behind it because 1st gear is a little above 3.00 and the second overdrive is in the low .6s. That's attractive for the speeds I'm running on the highway. The 6L90e has a deeper 1st gear for launches, but no other advantage I know. If I could get 12 mpg out of the combo, I'd be rocking.