SBC 400. A whole different animal?

[Cowboy_Customs]

Ok. this thread http://forum.73-87chevytrucks.com/smforum/index.php?topic=6942.0 got me wondering.

Whats different about a 400? Are they any good stock? Reason I ask is im looking into buying a 79 K30 with one in it with 77K original on it. This would be just a work truck for me, plowing snow, gettin lumber and so on. U know, a TRUCK! SO, is the 400 worth throwin a good intake, carb, and headers at?

Also any info/specs on the 79 truck 400's is greatly appreciated (compression ratio, head flow CFM numbers, ect ect). Thanks guys!

[Captkaos]

400's have siamese cylinders and only have steam passages to the heads.  Some people don't like them because they could run hot.  I don't think you would have a problem with one.

[Stewart G Griffin]

Good torque engine.  If gas were a little cheaper, i would actually want one of these for the truck.  Chevy or Pontiac 400.

[VileZambonie]

I had a 400 in my 1980 and loved it.

[CHawk]

In the process of finishing up the 400 swap (from a 305) in my '85 K10...hope I'll love it!

[78BBSTEPSIDE]

Back in 1977 dad had a brand new blazer with the 400 and was so proud of it until the sunday afternoon drive up over Berthoud Pass, west of Denver. All of the sudden a mid 70's International Scoutt II came by us like we were parked and taking in some sight seeing attractions. Dad always missed the big blocks and for a reason. That is why I replaced the 350 in his 78 PU with a mild 454 which is now my project stepside.

On another note I had a little 75 Vega in High School that had a 400 with a good set of angle plug heads, an edelbrock tunnel ram and too much carburetion and a healthy cam. It was sure fun to thrash at Bandimere, the local drag strip. It would be slow by today's standards, but back then it would run with the best and was a kick to drive.

[bigkountry]

I have a built 400 that can roast the tires on command (with 3.73's) . I had the heads drilled for coolant while they were beign redone. I put a 160 stat in it and the highest I have had it is 180...it NEVER runs hot. They are torque monsters for sure, but not real good on the MPG...lol

I always wanted a 400 for ym truck and ended up finding a complete engine for $50, guy couldn't get it to run and bought a new crate engine. Brought it home, switched the plug wires around and fired it on the stand..ran like a top but I tore it down anyways.

Sorry for the ramble...yes they are good engines...lol

[TexasRed]

bigkountry, do you think you would get better mileage if you would get a higher thermostat (such as 180)? I know you're worried about overheating, but if you've got a relatively good radiator, transcooler and heater core, you should be ok.

[cracker0169]

On a carbed motor, a low thermostat (or no thermostat for that matter) wont hurt the fuel economy as it will in an injected motor. Injected motors read the coolant temp and spray extra fuel to get the engine up to the factory ideal 195. Thats why you see alot of the programers for injected motors recommend running a 160 or 180 thermostat.  Me personally, I dont run a thermostat in my 4x4. I have an electric fan that is ran constant with no thermostat. My truck can idle for a couple hours solid and never get hotter than 145. If I'm on the trail or in the mud, and laying on the loud pedal, I might see 155.

Sorry about the rambling. As far as the 400 set up, I'd throw on an intake, carb, and a set of headers with good exhaust. While I had the intake off, I would throw in a cam with good lift and low duration.  I got a good cam I'd trade ya new in box for that Dana 60 ya got up front

[blast]

My truck can idle for a couple hours solid and never get hotter than 145. If I'm on the trail or in the mud, and laying on the loud pedal, I might see 155.

Aren't you missing out on some horsepower by not running the engine at factory specs?  145 seems very cold, I heard that was bad.

[VileZambonie]

The colder the coolant temp the more loss of efficiency. You can only keep the engine so hot before you either boil the coolant into a vapor or cause metal distortion or to the point of having abnormal combustion taking place but you want it as hot as possible so there is less wasted thermal energy. The cooling system sucks the heat out of the cylinders so the bigger the difference the more thermal loss. It won't hurt the engine just hurt the overall economy. Some people prefer playing it safer some try to squeeze ever penny out of their fuel.

[cracker0169]

Lets be honest here, 37 inch tires dont offer up the best economy to begin with. I prefer to play things safe. The cooler that engine stays, the less chance of some type of odd detonation occuring in the chambers. My theory is that I will have a less of a chance to crack a head hitting water or a mud hole if my coolant is at 130 degrees vs. hitting one with temp of 195 degrees.

I saw some gm 6.5L oil burners do some funny things when I was in Iraq. I saw temp gauges exceed 265 degrees... you are asking for things to start melting down internally.  Thats my $.02

[bigkountry]

My truck doesn't see much road use, just back and forth to work every now and then, about 30 miles round trip. I have a 4 core and 10K GVW trans cooler ( I think it might be a tad big) I also have a set of flex a lites sitting in my shop ready to go on.

She is basically a work horse on the farm, but I am trying to spruce her up a bit.