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#1 |
Registered User
Join Date: Oct 2007
Location: Minnesota
Posts: 24
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400 BB vs 350
Got my eye on a couple different trucks. One of them is a 72 c20 with a big block 400, others are 350's. Wondering what peoples opinions are on the 400, good / bad , problems , costs , ect. I like the idea of a big block, but have never heard much about this motor. Any thoughts are greatly appreciated !
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#2 |
Registered User
Join Date: Dec 2006
Location: Idaho
Posts: 210
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Re: 400 BB vs 350
Parts are more expensive. Expect around 10MPG if that's important to you.
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72 C2500 LWB 402 Sierra Grande 05 Odyssey 08 Tundra |
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#3 |
Registered User
Join Date: Oct 2007
Location: Minnesota
Posts: 24
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Re: 400 BB vs 350
Millage would not a big issue, would just be something to put around in from time to time. Wondering more about power and reliability.
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#4 |
Registered User
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Location: Charlotte, NC
Posts: 49
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Re: 400 BB vs 350
I'm in the midst of rebuilding one now. Cruiserman is right, can be more expensive, but as with anything it depends on what you're expecting perfomance-wise.
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#5 |
Registered User
Join Date: Oct 2007
Location: Minnesota
Posts: 24
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Re: 400 BB vs 350
Both engines would be primarly stock. Just didnt know if there was any great advantage to having that 400. Im assuming it would have a little more hp and torqe.
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#6 |
Senior Member
Join Date: Sep 2004
Location: Terrell, TX
Posts: 1,967
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Re: 400 BB vs 350
It should....is it a 402, 396 or a 400? If it's a 400, it's a small block as well. Both the 396 and 402 are more powerful than a stock 350. The advantage is the truck will be faster and more than likely more valuable if sold.
Disadvantages are that parts are higher and gas mileage is less. That said anyone who buys a truck like this for mileage needs his head checked. I'd get the BB if it's in good shape.
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Kelly '05 GMC Sierra SLE Z71 Bone stock except for new bed rail caps. Last edited by Gray Ghost; 03-19-2008 at 11:03 PM. |
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#7 |
Registered User
Join Date: Oct 2007
Location: Minnesota
Posts: 24
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Re: 400 BB vs 350
Its the 402 ci
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#8 |
Senior Member
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Location: Alexandria, MN
Posts: 1,462
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Re: 400 BB vs 350
I own a 402 c20 and it is quite thirsty.... 10mpg is pretty accurate and in our colder weather i was around 7-8 on a few trips last month... welcome to another Minnesotan!!!
--Mike
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63 C20 2WD, 230/SM420/4.11 73K 68 C30 dump truck, 327,SM425,4.56 66K original 68 C10 2WD SWB Stepper, 250/3-tree/3.73 66K.... Wifes 68 Buick Skylark Custom Conv., 350/TH400/2.56 In our family since '79 69 GMC 1500 SWB 2WD, 350/TH350/3.73 posi... 70 K10 SWB 4X4 4-sp,ps, pb, tilt, buckets, console, sliding back window (Need AC parts) WIP 72 Chevy K20 4x4 350/350/205/4.56 donor 72 Vette 350/M21/3.70 posi, triple black and super fast 84 Olds Cutlass Brougham 350/2004r/4.11 was Dad's |
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#9 |
Account Suspended
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Location: Wichita KS
Posts: 1,599
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Re: 400 BB vs 350
The main difference is that you can actually see the gas gauge move down when driving 70 on the highway with the 402.
Honestly each engine has its pros and cons. The big block more power higher cost to fix. SB cheaper parts and easier to fix but less power |
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#10 |
Registered User
Join Date: Sep 2006
Location: League City, Texas
Posts: 732
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Re: 400 BB vs 350
My stock 402 truck has the 3.07 axle and I got 13 mpg city last time I checked.
The C20 you are looking at will probably be closer to 10 mpg as said above because of the gearing. |
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#11 |
Senior Member
Join Date: Sep 2004
Location: Terrell, TX
Posts: 1,967
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Re: 400 BB vs 350
402's are great motors. I know someone who drives one daily to his job in Dallas. He gets around 10 mpg in town if he feathers it....something I fail to be able to do.
I get 11-12 mpg [sb 350] with what's known as a lead foot. If I could feather it who knows? My '67 will probably be a big block....either a 396 or 402.
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Kelly '05 GMC Sierra SLE Z71 Bone stock except for new bed rail caps. Last edited by Gray Ghost; 03-20-2008 at 01:22 AM. |
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#12 |
Registered User
Join Date: Jan 2006
Location: Houston
Posts: 434
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Re: 400 BB vs 350
the parts are only more expensive for the BB if they don't come with the engine. I assume since you are looking at a complete truck the engine, brackets and power steering (if equipped) are complete. Water pumps, carburator, oil pump, alternator, distributor, regulator, power brake booster and cylinder, transmission, air breather, rear end, air conditioner, battery etc, would cost the same as a small block.
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#13 |
Senior Member
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Location: madison indiana
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Re: 400 BB vs 350
get the bb you will like it!!!
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#14 |
Registered User
Join Date: Sep 2007
Location: Grand Forks ND
Posts: 434
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Re: 400 BB vs 350
I had a big block in a chevelle and it was a beast. Some friends had chevelles with small blocks and not even close to the same power, I had way more torque and the gas milage wasnt that much worse, I would get 16-17 hwy they would get 17-18 hwy. It is also a much stronger built engine even in a two bolt block.
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"Beer is proof that God loves us and wants us to be happy" Ben Franklin ![]() 67 Chevy 1/2 lwb, 67 GMC 1/2 lwb (parts) |
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#15 |
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Join Date: Sep 2003
Location: Franconia,N.H.
Posts: 1,029
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Re: 400 BB vs 350
you got 17 out of a BB!
If gas mileage isn't a problem i would go BB. they're more fun and if you like loud pipes it'll definitely do it for ya.
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(Only) Member of the CPNE Fan Club ![]() ![]() 67 C-10 350 with 3-speed tranny and 308 gears swb step ![]() 82 Z28 Camaro 355 small block over 350 hp and a borg warner super t-10 (blown engine) 72 Chevy K20 Suburban (future project) 70 Chevy K20 now 68 GMC K2500 2003 Chevy 2500hd ccsb 4X4 (daily driver) |
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#16 |
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Join Date: Sep 2007
Location: Grand Forks ND
Posts: 434
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Re: 400 BB vs 350
it was the late 70s and early 80s the speed limit was 55zzz. The car had 3.31 gears and was turning 2500 at 60mph if I remember correctly
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"Beer is proof that God loves us and wants us to be happy" Ben Franklin ![]() 67 Chevy 1/2 lwb, 67 GMC 1/2 lwb (parts) |
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#17 |
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Join Date: Jan 2007
Location: Charles City IA
Posts: 1,626
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Re: 400 BB vs 350
the 402 is a .030 over 396 basically, and in the chevelles it was still called the 396 even after it became 402 in 1969, b/c ppl knew the 396 name they didn't know the 402 name, but in trucks it didn't matter
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'67 C20, Under the Knife!, LWB, Eaton HO-52, Rear Coil Springs 72' GMC C2500, 350, TH400(?), Dana 60 '67 K10 4-spd., 305, SM465, Dana 44, 12 Bolt, RUST! '65 C60 292, 4 spd, 2 spd Rearend, 15' Grain Box, MINT! 09 Yukon Denali 82k Miles 6.2L/6A |
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#18 |
Senior Member
Join Date: Nov 2005
Location: northwestern wi
Posts: 2,111
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Re: 400 BB vs 350
are they both all c20's if future may be lowering it you may want a c10but iwould go for an original bb truck if i had the chance
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#19 |
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Location: Hillsboro Oregon
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Re: 400 BB vs 350
My burb was a factory 396. First BBC I owned after several 350s. I liked driving the mostly stock 396 more than some of the modified 350s.
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#20 |
Senior Member
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Location: Williston, ND
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Re: 400 BB vs 350
Believe it or not, I got 15 in town with a 402 in a 72 sb 3.08 gears. I would buy the big block because you can always convert a 1/2 ton 2 wd later down the road if you want. Oh yeah, just look at my sig, too, you can see my obvious choice!!
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68 Chevy CST/10, 50th Anniversary, 327/th400, 373 posi, buckets 68 GMC Shortbox Stepside, 402/th400, Tilt, Tach, Bucket Seats, 3.08 Positraction 69 Chevy Camaro SS, 383, 4 speed, positraction 70 Chevy El Camino SS396, Triple Black, 454/th400, Tach 70 Chevy Shortbox Stepside 4x4, 350/th350, Tilt, Tach, Cab Lights, Bumper Guards, Tow Hooks 70 Chevy 3/4 Longbox, 350/auto, 70k, SURVIVOR 71 Chevy Blazer, CST, 350/auto 71 GMC Sierra K2500, 454, 4 speed, 4.10 posi, 37s 71 Custom/30, Open Road, 350/th400, tilt 72 Chevy Shortbox Fleetside, 496 Stroker/th400, Tilt, Tach, Bucket Seats, 3.42 Posi 72 GMC Sierra Grande 2500. 427/th400, tilt, a/c, tool and stowage, buckets/console, 3.54 posi |
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#21 |
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Join Date: May 2007
Location: Moore, Oklahoma
Posts: 2,396
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Re: 400 BB vs 350
I would probably make a decision on the truck itself first and the motor second. But if all other things were equal, i'd go for the BB.
But i wouldnt if the body was in worse shape -- etc etc
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#22 |
Special Order
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Location: Mt Airy, MD
Posts: 85,859
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Re: 400 BB vs 350
I agree with Streetstar.I`d buy the truck,not the motor.
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"BUILDING A BETTER WAY TO SERVE THE USA"......67/72......"The New Breed" GMC '67 C1500 Wideside Super Custom SWB: 327/M22/3.42 posi.........."The '67" (project) GMC '72 K2500 Wideside Sierra Custom Camper: 350/TH350/4.10 Power-Lok..."The '72" (rolling) Tim "Don't call me a redneck. I'm a rough cut country gentleman" R.I.P. ~ East Side Low Life ~ El Jay ~ 72BLUZ ~ Fasteddie69 ~ Ron586 ~ 67ChevyRedneck ~ Grumpy Old Man ~ |
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#23 |
Senior Member
Join Date: Sep 2004
Location: Terrell, TX
Posts: 1,967
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Re: 400 BB vs 350
Very hard to believe for me that anyone can get mid-high double digit mileage w/any size BB in ANY vehicle, much less a brick shaped truck. Maybe if you drove like 10 mph under all the speed limits and creeped off the lights, I could see a snowball's chance, but I am pretty sure there aren't many of those drivers here. Sorry guys, I can't buy it....I'd have to see that in person to believe it.
I know a guy who drives a 396 LWB everyday....swapped to a 1406 to get better than 9mpg in town...now he gets 10! The motor is relatively fresh and the axle ratio is a 3.08 non posi. On a really good day with a tailwind he might get 12 on the hwy. If you do your math correctly, most of you will find these numbers are very close to what you get unless of course you are running a four speed auto.
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Kelly '05 GMC Sierra SLE Z71 Bone stock except for new bed rail caps. |
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#24 |
Registered User
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Location: Hillsboro Oregon
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Re: 400 BB vs 350
streetstar nailed it.
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#25 |
All stock and staying that way
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My 4.10 ratio equipped C/20 402 usually averages 11. I just installed a new tonneau cover, I might get 12...
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