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400 sb vs. 94 350

 
Pontiacman350
I love my Chevy Chevette!
Posts: 18
Joined: 07/13
Posted: 07/22/13 07:52 PM

Hey I was wondering if somebody could tell me what would be better for my project, a rebuilt fuel injected 350 I have the intake to change it to carb and have everything all priced up for the swap and I might be able to get a 400 small block from a 80 3/4 ton chevy for around the same price, i was told it has a steel crank? and it runs no noises. What would you get?  

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68scott385
I mow my lawn and find Chevys
Posts: 1994
Joined: 10/09
Posted: 07/23/13 06:54 AM

I'd go with the 400 for the additional torque available from the longer stroke but if it has never been apart it may be getting close to needing a rebuild.  
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Pontiacman350
I love my Chevy Chevette!
Posts: 18
Joined: 07/13
Posted: 07/23/13 07:33 AM

I'm not sure if it has been apart or not. Any special way I can tell its a 400 without a number when I go and look at it?  

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68scott385
I mow my lawn and find Chevys
Posts: 1994
Joined: 10/09
Posted: 07/23/13 10:54 AM

The balancer and flexplate will have more weight on one side than the other. Look at the balancer on a 350 to see how it's a concentric circle, smooth on the outside with no portions machined out, a 400 balancer has some of the mass removed on one side of the balancer.  
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skyeking
I mow my lawn and find Chevys
Posts: 2738
Joined: 08/09
Posted: 07/24/13 05:06 PM

Hi there,
The 350s outweigh the 400s in reliability and spares in every way.
 No siamese bores etc and go to what you know. getting 370 lbs of
torque is all you need with average gearing and is no big project
to get. Whatever you choose good luck...Skyeking..  
skyeking

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Pontiacman350
I love my Chevy Chevette!
Posts: 18
Joined: 07/13
Posted: 07/24/13 06:27 PM

I'm still not sure If I can get this 400 for sure but if its not going to be as good if a motor as the 350 I won't bother, I'm just looking for the best bang for my buck and what will give me the best power  

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68scott385
I mow my lawn and find Chevys
Posts: 1994
Joined: 10/09
Posted: 07/25/13 07:25 AM

As you can see by the mixed responses, it is a personal preference call. Me personally, I would get the 400 and if it needed to be rebuilt then so be it but realize that it is not the same animal as the rest of the small block family. The most important factor here is that you need to be comfortable about the decision you make and the engine you feel comfortable with and weigh the opinions you've asked for as our own choice of the options.  
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waynep712222
I have an SS396 tatoo
Posts: 251
Joined: 03/13
Posted: 07/25/13 07:45 AM

one thing.. unless its an aftermarket crank in the 400.. its going to be cast iron..

as far as i know.. there were never any forged steel 400 small block cranks made by GM.. at least for public sale..


i would choose the 350 over the vintage 400 ..  

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redneckjoe69
I mow my lawn and find Chevys
Posts: 2337
Joined: 03/10
Posted: 07/25/13 02:45 PM

what kind of fuel injection does the 350 have?    it could have a factory roller cam?    get the casting numbers, then you can look it up.

   the 400 is mighty tempting too! Grin  

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Dave632
I mow my lawn and find Chevys
Posts: 2253
Joined: 07/08
Posted: 07/25/13 03:19 PM

Personally I always went for cubic inches, that where the 632 comes from. However in this case the reliability of the block is in question since some members question that so would I as I never ran one. A cast crank is OK as long as you are not going for a high rpm race motor. For a street car with an occasional trip to the track you should be OK.  
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Pontiacman350
I love my Chevy Chevette!
Posts: 18
Joined: 07/13
Posted: 07/25/13 03:38 PM

Scott what do you mean a different animal than the rest of the small blocks? Different how? And redneck joe I did look up the numbers and it said that the year it was man there some roller and some that were not. Thanks for all the comments!  

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68scott385
I mow my lawn and find Chevys
Posts: 1994
Joined: 10/09
Posted: 07/25/13 06:16 PM

The 400 has siamesed center cylinders on either bank meaning that there is no coolant passage between them like all other small blocks. The cylinder heads used on the 400 block also have to have steam holes in them or the motor will over heat. These are two distinct differences that no other displacement in the gen1 family has to deal with. The harmonic balancer/damper and the flexplate/flywheel also have offset weight for the rotating assembly to be balanced, again the only motor in the gen1 family like this.

Just some things to be aware of when building a 400sbc.  
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redneckjoe69
I mow my lawn and find Chevys
Posts: 2337
Joined: 03/10
Posted: 07/25/13 07:27 PM

hey, whats the motor going in?

  any info on the project at hand?  

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WScott
V-6 Camaros rule!
Posts: 40
Joined: 03/12
Posted: 07/26/13 06:21 AM

i put a 400 sb out of a 75 full size chevy back in 1994, it was a 2 barrel rated
at 175 factory hp. into a 67 chevelle, it replaced a 350 sb, the 400 moved
the car so much easier than the 350, would smoke the tires and accelerate the car
quicker out of the hole even in the stock condition, the 350 was a four barrel
engine with small cam and headers, both using a 3 speed turbo 350 trans. with a
3.08 rear gear and 26" tall tires,the motor ran great even with the points ignition
system, never over heated, today as i type this the engine is still in our 67 chevelle but in 406 trim, mutha thumpr cam, trick flow aluminum heads, full roller
1.6 rockers, rpm air gap with a 750 holley carb , 1.3/4 headers into full 3 inch
exhaust, msd ignition, 3.55 gears with a 4 speed stick, gotta say the car is quite
quick, got 28" tall M/T sportsman pros on the back, tuned suspension and it is still
hard to get traction, in my opinion cu inches are still the way to go and to pick up
an extra 50 cubes on an engine with the same overall dimensions seems like a great deal and would make a great project, also even if you go with the 350, BUY THE 400 and save it as  these engines are getting harder to find, at least
where i live, in a nut shell if you go with the 400 pay close attn to the cooling
system, rad, rad shroud thermostat and what ever else to keep it running cool, mine always runs at 180, i really love my big sb  

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skyeking
I mow my lawn and find Chevys
Posts: 2738
Joined: 08/09
Posted: 07/26/13 06:24 PM

Hi there people,
" Let the Buyer Beware".  
skyeking

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