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**70STOVEBOLT** · 04-30-2016, 07:47 PM

I had a 250 with a TH400 and 3.73 gears in my 70 SWB and it got 13-14. Maybe 15 with a tail wind on the highway. It was my DD for 14 years in that configuration. Now it has a 402 and it gets 11. It has a mild cam and an Edelbrock 750 carb with HEI. Other than that, it's all stock. I did not buy the truck because I wanted something that would get good fuel mileage. I just love to drive it. It is loud right now, but it only has 2.5 inch pipes to Thrush turbo mufflers that are right under the front of the bed, and no tailpipes. It will be fine once I get a proper exhaust system on it. There is no replacement for displacement!

04-30-2016, 07:47 PM	#27
70STOVEBOLT Senior Member Join Date: Jun 2005 Location: Winona Lake, IN Posts: 6,568	Re: Will Big Block be TOO MUCH? I had a 250 with a TH400 and 3.73 gears in my 70 SWB and it got 13-14. Maybe 15 with a tail wind on the highway. It was my DD for 14 years in that configuration. Now it has a 402 and it gets 11. It has a mild cam and an Edelbrock 750 carb with HEI. Other than that, it's all stock. I did not buy the truck because I wanted something that would get good fuel mileage. I just love to drive it. It is loud right now, but it only has 2.5 inch pipes to Thrush turbo mufflers that are right under the front of the bed, and no tailpipes. It will be fine once I get a proper exhaust system on it. There is no replacement for displacement! __________________ 70 C/10 SWB 402/TH400/3.73 "The Needy Beast" 200,000 Mile Club Disc Brake Club Owner installed options: Front Sway Bar Power Steering Power Brakes Cigar Lighter Courtesy Lights Deluxe Side Markers Wiper Delay Sliding Rear Window Power Windows Power Locks Sniper EFI 2015 Silverado 1500 LS 4.3/6L80/3.23 lowered 2" front & rear Last edited by 70STOVEBOLT; 02-20-2017 at 07:21 PM.