400 BB vs 350

[SWILL]

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 !

[cruiserman]

Parts are more expensive. Expect around 10MPG if that's important to you.

[SWILL]

Millage would not a big issue, would just be something to put around in from time to time. Wondering more about power and reliability.

[trebeck]

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.

[SWILL]

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.

[Gray Ghost]

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.

[SWILL]

Its the 402 ci

[tkeduk8r]

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

[ksjh1316]

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

[Texasdeere]

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.

[Gray Ghost]

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.

[stope4]

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.

[jamie72]

get the bb you will like it!!!

[bhoeger70]

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.

[CPNEJR]

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.

[bhoeger70]

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

[ed2552]

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

[wibilly]

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

[Frizzle Fry]

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.

[68350]

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!!

[streetstar]

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

[special-K]

I agree with Streetstar.I`d buy the truck,not the motor.

[Gray Ghost]

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.

[Frizzle Fry]

streetstar nailed it.

[1970cstblazer]

My 4.10 ratio equipped C/20 402 usually averages 11. I just installed a new tonneau cover, I might get 12...