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Mod | | | Forums66 Topics128,138 Posts1,056,751 Members48,454 | | Most Online14,466 Apr 26th, 2026 | | AD Chevy Trucks Over 6,000 pictures Brad Allen has an awesome collection of Chevrolet factory pictures that he has set up from film strips. Check them out!
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on the Internet for over 30 years! and not clogged down with Ads! Again, thanks! | | | | Joined: Sep 2008 Posts: 293 'Bolter | | 'Bolter Joined: Sep 2008 Posts: 293 | here is the thing: I have a '57 Suburban with a Camaro front clip, rear suspension and 250ci inline6/th350 (in very good conditions). I would like to improve a bit on the powertrain, I have a few engine ideas that I need help sorting. What matters most to me is daily driving reliability, then some more liveliness, and reasonable fuel economy. The project has to be as cheap as possible, too! I appreciate comments, experience, I like numbers, in particular fuel economy. Here is my short list of engine: ~ L6 diesel from a Dodge Sprinter: ideal engine, but too rare, too expensive, difficult swap, so this one is a no-go, sadly; ~ 4.8 or 5.3 EFI modern truck engine:reliable, easy to maintain, power/torque probably more than I need, but what about fuel economy? ~ my 250ci with intake/exhaust manifold (Clifford), GM throttle body EFI, good exhaust line: what power/torque/economy will I get? ~ same as above but with a turbo (with a Brazilian manifold): could be a bit expensive and fear bad gas mileage. Any other ideas? Go ahead, fire up your commenst, experiences... Thank you!
'57 Chevy Suburban; '70 Chevy Impala.
| | | | | Joined: Sep 2009 Posts: 66 Wrench Fetcher | | Wrench Fetcher Joined: Sep 2009 Posts: 66 | My personal preferences would be to either freshen up the 250 and add the turbo if it's in the budget, or put in either a 283 or 305 sbc. With the 250 you have your original engine and decent mileage. I believe the aftermarket intake/exhaust and turbo would both slightly improve mileage and give you a power boost, but I could be wrong. If you swapped it out for a small v8 you would still have a solid, reliable engine but you would have more power at your disposal. Your mileage would drop some but should still be reasonable. I don't know any numbers off the top of my head about power gains etc as I am fairly new to this but those would be my two choices. As far as going to EFI, I would avoid that. EFI is really nice... when it works. I prefer carbs because they are mechanical and I can work on them, I'm not dependent on a computer that way. But that's just my opinion, if you want EFI go for it  | | | | | Joined: Apr 2005 Posts: 1,971 'Bolter | | 'Bolter Joined: Apr 2005 Posts: 1,971 | I'd go with the 5.3 EFI. My truck gets 17.5 on interstate.
My Chevy PU with a 4.3 will get a little better if I slow down a bit. | | | | | Joined: Aug 2007 Posts: 1,859 Grumpy old guy playing with trucks, cars, and boats | | Grumpy old guy playing with trucks, cars, and boats Joined: Aug 2007 Posts: 1,859 | Atlas engine. 4.2 from a trailblazer. Then get ahold of DIYEFI and put a turbo on it for some insane power.
A racing friend of mine describes carburators as "Kohlers Finest" While they may be easy, they do rob fuel economy and driveability.
If you turbocharge the 250, you have some homework to do to make sure that you dont run it too lean which will melt all your pistons and just ruin your day.
A good choice would be a cummins 4BT or 6BT(like the one in the sprinter). Available out of many chassis, including Dodge from 1989 to today.
The problems we face today can not be addressed at the same level of intelligence we were at when we created them - Albert Einstein Or with the same level of $ - Me
| | | | | Joined: Dec 2003 Posts: 1,554 Shop Shark | | Shop Shark Joined: Dec 2003 Posts: 1,554 | Wave 1957.As I have posted before,there are a lot of things that give you good fuel economy.Most of all being your final gear ratio,and also what type of tranny you use. In my 1955 I have a very healthy 350 GM engine hooked up to a 700R4 OD tranny,then into a stock 3:90 rearend.20 MPG all day long,as long as I drive like a human being.The 700R4 is running a .78 to 1 in the top gear,and this going to the 3:90 rear works out very well.I could go all the way to a 4:11 rear and still get good mileage.So in my opinion,get your gearing right and drive sensibly,and you will be OK,no matter what engine you use.If you use a 350,or 400 turbo or a standard with 1 to 1 output you will need to go with possibly a 3:08 or 3:23 rearend for fuel economy.Good luck.
Last edited by dale937; 10/22/2009 12:47 PM.
| | | | | Joined: Dec 2007 Posts: 180 Wrench Fetcher | | Wrench Fetcher Joined: Dec 2007 Posts: 180 | I agree with the 5.3 they are very cheap now and unmatched driveability and fuel mileage. you can pick up a complete package engine, trans, harness and all for around 2K. thats hard to beat | | | | | Joined: Nov 2008 Posts: 25 New Guy | | New Guy Joined: Nov 2008 Posts: 25 | I am going with the 5.3 out of a Chevy pickup in my 1955 2nd. Go with either the 4.8 or 5.3 they will run 250,000 all day if taken care of, get great mileage plus performance. They can bolt up to any GM transmission, turbo 350, 400, 700R4, or 4l60E. I have started working with these LS engines, and haven't looked back. I have sold all of my old small block stuff. Where else can you get 300hp, 6 bolt mains, aluminum heads, modern engineering, and great gas mileage? Also, an engine that doesn't develop oil leaks over time! Go to "ls1tech.com" and look under their "Hybrids and Conversions" sections. They are installing these new GM engines in everything now. There is tons of support and aftermarket on these engines. You can stay with fuel injection, or you can install a carburator intake, MSD ignition box and off you go! Just my 2 cents, but I am having fun with mine. | | | | | Joined: Sep 2006 Posts: 841 Shop Shark | | Shop Shark Joined: Sep 2006 Posts: 841 | i would stay with the 250, it's the only one measured in cubic inches.  liters and fuel inj are a slipery slope. | | | | | Joined: Dec 2001 Posts: 14,522 Moderator: Welcome Centre, Southern Bolters, Legion Hall | | Moderator: Welcome Centre, Southern Bolters, Legion Hall Joined: Dec 2001 Posts: 14,522 | .... if you have excess to a 327 I think it would be nice in your truck. | | |
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