Author Topic: Small Block 350 vs 400  (Read 84456 times)

Offline BlueCollarRon

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Small Block 350 vs 400
« on: February 21, 2009, 06:28:11 PM »
So here is my dilemma.  I had a 350/350 in my '82 swb GM and I busted my crankshaft.  That old block is complete garbage.  So now I have a early 80's 350, or a 400 that is sitting in a 79' Chev in the yard.  I plan to compete my truck in the mud drags, so faster times the better.  On the other hand, I will be tearing it up with friends on the weekends.  Lots of those trails are very long so....

In your opinion which would be the best option from our choices above?

I found this interesting read from another forum
http://www.greatlakes4x4.com/showthread.php?t=120939

http://www.youtube.com/watch?v=jkfGuDhB8_c
Utube: 350 races a 400

Thanks
Ron
« Last Edit: February 21, 2009, 06:29:50 PM by BlueCollarRon »

Offline jwag30

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Re: Small Block 350 vs 400
« Reply #1 on: February 21, 2009, 09:12:21 PM »
theres no replacement for displacement! 
Speed is only a matter of money. How fast do you want to go!

Offline 78 Chevyrado

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Re: Small Block 350 vs 400
« Reply #2 on: February 21, 2009, 10:07:53 PM »
I'd get a 400 personally, bigger is better in the same size package, but if you broke a crank, whichever engine you get you need a forged crank and rods instead of the stock cast crank.  everybody hates 400 because they have heard this or that about cooling.  most people who have had them love them.  As long as you have steamholes in the right spot in the heads, no other equivelent small block can touch a 400.  nowadays with everybody going to 383's.  IMO 350's are the new 305, and 383's are the new 350.  I'd reuse a 350 for the same reason one might reuse a 305.  you already have it, or for a tad better fuel mileage.
« Last Edit: February 22, 2009, 02:58:37 PM by 78 Chevyrado »
Kenny

1978 C-20, 350/400, 3.73, Graystone Metallic, Raceline Renegade 8 Wheels - 18x8.5, 275/70R18 BFG KO's

Offline Lt.Del

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Re: Small Block 350 vs 400
« Reply #3 on: February 22, 2009, 08:00:12 AM »
Get a stump puller!!

I didn't see an option to vote on a 383 stroker ;D 

Offline VileZambonie

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Re: Small Block 350 vs 400
« Reply #4 on: February 22, 2009, 10:51:55 AM »
Why would he build a stroked 350 when he already has a 400? The 400 is a nice small block and it's too bad they stopped making them. A few things to keep in mind with the 400 is build it for what it's meant to be and have a good cooling system. You will need to either get a set of drilled heads or drill a set of heads for the steam holes. I had two 400's and both of them were awesome. Keep the compression ratio streetable and use a dual plane intake manifold and don't go too crazy with the cam.
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Offline BigHemi353

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Re: Small Block 350 vs 400
« Reply #5 on: February 22, 2009, 12:04:35 PM »
My friend had a mean 79 k5 with a 400 with mild mods(not exactly sure other than intake and headers) that i was going to put through the mud bog at our county fair. It was a fast sucker. i worked hard getting that thing ready, fix tires, fixed the hubs, replace belts, ect. he had it for sale sign on it after i got it signed in there and sold it an hour before i was going to race.  :'( It did great and place pretty high.
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Offline 78 Chevyrado

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Re: Small Block 350 vs 400
« Reply #6 on: February 22, 2009, 02:51:03 PM »
My friend had a mean 79 k5 with a 400 with mild mods(not exactly sure other than intake and headers) that i was going to put through the mud bog at our county fair. It was a fast sucker. i worked hard getting that thing ready, fix tires, fixed the hubs, replace belts, ect. he had it for sale sign on it after i got it signed in there and sold it an hour before i was going to race.  :'( It did great and place pretty high.

That would piss me off >:(
Kenny

1978 C-20, 350/400, 3.73, Graystone Metallic, Raceline Renegade 8 Wheels - 18x8.5, 275/70R18 BFG KO's

Offline hilton850

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Re: Small Block 350 vs 400
« Reply #7 on: February 22, 2009, 03:16:27 PM »
the 400 gets my vote too...Vile has some good advice about the steam holes.  I posted a link in another thread on here about a 400 sb with airflow research heads that made 490 hp and 529 ft-lb.  Sounded like a good build, and if your budget doesn't allow they built the same engine with vortec heads and 1.5 ratio rockers (they used 1.6 ratio with the afr heads).  Other than that everything was the same including the cam...that version made 427hp and 515 ft-lb or something like that. 

Might be worth mentioning that the combo with the afr heads could run 87 octane iirc and they had to run 93 in the vortec headed one. 

either way I think it could be done on a budget and you could upgrade to the afr heads down the road.  that much torque would make anything go like a $#*().  They did all this with a stock 400 crank, evidently they're pretty strong.   
'84 Sierra 3/4 ton.  4 on the floor, 4 wheel drive, upgraded to FM radio and steelhorse seat.  383 stroker under the hood - 430 hp 440 ft-lb.  custom rust holes in the bed and both rockers and cab corners.

Offline Russ130

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Re: Small Block 350 vs 400
« Reply #8 on: February 22, 2009, 05:39:33 PM »
You would probably do better with a 327 turning high rpms. Mud bogging is all about rpms of the tires and floatation. Look for high rpm hp and don't worry about torque too much just make sure you have enough to get it up to speed. 327 uses the 350 bore and a 3.25 stroke crank as opposed to the 350's 3.48 stroke. Plus with the internal balance higher rpms are going to come a lot easier than destroking an externally balanced 400.

Offline 406 Q-ship

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Re: Small Block 350 vs 400
« Reply #9 on: February 22, 2009, 06:01:22 PM »
Do the 400 with a 5.7 rod lenght.  383 don't breath as well as a 400 due the smaller bore that shrouds the valves.  A 350 just has to work harder to get the job done and if you already have the 400 SBC then it is a no brainer.  Forget the highwinding 327 if you drive this thing and do mudbogging on weekends, all that will happen with a 327 that you have to daily driver is a temperamental engine that wears out faster due to the low gearing.  Highwinding equals big cam which means higher compression that leads to no street driving because big compression will not run on pump gas.  I have a 406 that was built in the late 1980's for a magazine article (Strong Arm 406) in a Monte Carlo that runs high 12's on pump gas,drives on the street like a dream, and it does just like a late model car (starts without a hassle in the cold, runs with a shorter gear and pulls down 17 mph with a TH400)

Another consideration if you are willing to get another engine.........Oval port 396/402 BB with a hyd roller Cam, easy to build big torque, cheap to build cause it is out of not so saught after pieces.
« Last Edit: February 22, 2009, 06:05:50 PM by 406 Q-ship »
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Offline Captkaos

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Re: Small Block 350 vs 400
« Reply #10 on: February 22, 2009, 08:33:51 PM »
Go as big as you can afford for bogging.  You can build a 400 to spin just like anything else ( buddy built one that would spin to 8000rpms), 327 would just have to work harder for the same amount of power.   No brainer..  400.

Offline Lt.Del

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Re: Small Block 350 vs 400
« Reply #11 on: February 22, 2009, 09:48:44 PM »
Quote
Why would he build a stroked 350 when he already has a 400?

I'm gonna steal a line from my 4-yr old boy....."Because!".

I dunno, never had a 400, but, I have a 383 and that puppy has loads of torque.  Torque is what makes an  engine go.  'tis why they are called stump pullers.  Love mine.  Anyone else would love there's.

But, as mentioned, c.i.d. is  boss.  Go with displacement--i'm outvoted www.delbridge.net/install

Offline Russ130

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Re: Small Block 350 vs 400
« Reply #12 on: February 22, 2009, 11:42:47 PM »
Look guys, stating your opinion as fact is just plain, well uneducated.
Fact #1 the 327 had the highest hp output of any naturally aspirated production gm sb engine until the 2002 Corvette z06
Fact #2 the 2002 z06 engine was a 350
Fact #3 the 08  Vette engine is 366ci
Fact #4 the 400 was only manufactured for 10 years, if it was so good why only make it for 10 years? They still made big blocks so the mpg thing is out the window.
Fact #5 the 400 was never used in the Corvette by gm which being the flagship Chevy car always got the best motors, yet the 327 was and so was the 350 as well as big blocks odd isn't it how the 350 and 327 are the 2 most popular corvette engines. I find it also interesting how during the 70's while the 400 was being produced the 350 was the base corvette motor.
Anyone ever wonder why most 400's output was around 250 hp which is around 100 hp less than the 327's? Ever wonder why gm did away with the 400?
A 400 turning 8000 rpms? On a daily driver? On a budget the OP could afford? That's a pretty big claim.
Why didn't GM bring back the 400 in the second generation small block? There has to be a reason especially with the Mustang walking all over everything Chevy made in those years.
Capt - I beg to differ with you. Getting a 327 to turn 8000 reliably is going to cost a lot less than a 400. A 327 makes 350 hp with a hyd cam, they actually call it the 350 horse 327 cam. You could drop a hyd roller cam in and get 400 hp. I think that should be all the power it would need and it can live in the 6000 rpm range all day long and be perfectly streetable, actually tame. Simple physics proves the shorter stroke of the 327 will spin faster than the longer stroke of the 400 or even the 350. The crankshaft even with no pistons attached will be capable of spinning faster. Have you ever watched a figure skater do there spin move? Did you happen to notice as they brought their arms and knees in towards the center they speed up? When their arms are out can be thought of as the longer stroke than when everything is close to the center line.
I agree that a big block is a better choice if it can be afforded because then the jump in horsepower allows you to use gearing to get those tires spinning at the right rpms. As an added benefit the bbc would still be very streetable.

Offline 78 Chevyrado

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Re: Small Block 350 vs 400
« Reply #13 on: February 23, 2009, 12:27:53 AM »
The 400 died because of emissions and no more huge cars.  they were for torque in those big cars with better mileage than a 454.  I agree the 375/327's were bad little engines, but a bear to drive on the street and a pita to maintain with the solid lifters.  but either way, if the 327 was so great, where is it now?   Also you said the if the 400 was so great how come they only made ot for 10 years, so why were 327's only made for 8 years.  Ask lots of dirt track racers if they use 327s or 400's (rules allowing)  they turn 5000+rpms.  By the time the 327's went out, everything else was being choked by emissions junk, so of course they cant perform like that.  The reason big inches is better is that you don't have to hop it up as much to make the same power, giving better reliability and driveability.  if they had went all out and set up a 400 like they did that 375hp 327, we'd all be talking about that super impressive 400 chevy used to make.  IF you set it up correctly, ANY chevy small block will turn 7000rpms all day.  i see what you're saying about the physics, smaller stroke, less mass to move a shorter distance.  the stroke difference between a 327 and a 350 is about the same as the difference between a 350 and 400.  how many 327's turn 8000+ rpm's like 350's (with longer less capable strokes) in NASCAR and do it for 500 miles straight?  327 was just a stepping stone, like every other engine chevy has made or will make.  Cubes make the difference, as an extreme example would you race a chevy small block 265 or a big block 572 for pink slips.
« Last Edit: February 23, 2009, 12:31:31 AM by 78 Chevyrado »
Kenny

1978 C-20, 350/400, 3.73, Graystone Metallic, Raceline Renegade 8 Wheels - 18x8.5, 275/70R18 BFG KO's

Offline BlueCollarRon

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Re: Small Block 350 vs 400
« Reply #14 on: February 23, 2009, 12:48:23 AM »
Cool, great thread and info.

I'm definitely going with the 400, and I will build it up as much as my cash allows.  Down the road I would like to bore it out, but for now I am going to swap motors and swap the carb from my 350 to the 400.  That will get me back on the road for a while, at least until I get more cash.  I still have another month until I can even think about spring.

So correct me if I am wrong, but I need heads with holes drilled in them to let out steam!?  Is that a major problem with the 400sb for those without drilled heads? 

I have read that due to the motor being externally balanced it can cause problems.  What should I be worried about?

For the cooling system, as long as I have a fan for the radiator what more could I do?  Would a fan even be beneficial?

Even though I made my mind up, keep the debate going, I'm learning a lot! :o


Small Block 400



Small Block 350
« Last Edit: February 23, 2009, 12:55:05 AM by BlueCollarRon »