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Budget 383...Is there such a thing?

tch777 said:
So what is really better when on a budget: 383 or swapping in a 400?

Just wonder cause next year I am going to find a builder block to build up a new engine for the Suburban so I can keep in on the road and just swap out the engine before it dies. I have to pass emissions and keep all my TBI stuff too.

Tim
Click to expand...

I asked that same question and there were way too many negatives on the 400. I ruled that out, and now I'm deciding if I just want to build my 350 or spend a little more and go with the 383. I'm sure those here that know MUCH more than I do will respond.
 
I would go with a 355 with a good set of heads personally. That way you save all the clearance issues and some money. Put a good set of aluminum heads mild cam and an aftermarket throttle body and you will come out cheaper, make close to the same horsepower (however at higher rpm's) without worrying about emissions as much. But thats just me :o
 
I don't give a damn about emissions, the truck is green stickered. So no smog test.

A 355 is a good idea though. Somethin else to think about. :wink1:
 
hmmm, how much would it cost to go to 355? would it be worth the money to do that and still keep the tbi, or would results really only be noticed going with tpi?
 
TPI would definately be better in my oppinion. But I have ran them with TBI until funds were availible. Worked fine just didn't make as much power depending on cam size, heads, etc.
 
Sorry for the ignorance but what negatives are there to the 400?

Also is a 355 just a oversized bore on a 350?

So most bang of the buck is rebuild the 350 using a .030 ovesize bore.
And then slap on some good heads and a better cam? This would result in less spent than a 383 with similar performance?

And I did try searching but the search thingy sucks.

Thanks

Tim
 
400 blocks are prone to cracking in the lifter valley area and the heads also are prone to cracking.

Yes a 355 is nothing more than a .030" overbore on a 350. It will not produce the same amount of low end torque that a 383 will but it will still run good. Power is made in the heads and valve train so keep that in mind when choosing what to buy and where to skimp.
 
So is it a myth about these 400 small blocks or is it more of a documented fact that they crack? Just wondering since all I ever heard was they overheat easy, but I figured a blig block 4 row radiator would fix that.
Also just wondered since I have seen a lot of references to people going with 406 s for more power and torque.

Thanks

Tim
 
you'll gain about 3 hp and 3 ft lbs over a 400 with a 406. all it is is a bored out 400.

350's are known for crackin heads where theres only about 1/16th of an inch of steel seperating the valves... most of the time you won't know unless you get it magnufluxed. But like the 400 it has to get HOT before that happens.
 
Back in the old days (80s), I was involved in dirt track racing. I helped build and was around ALOT of 400 sbc engines. Stock cast crank, balanced and polished rods, sometimes stud the mains, sometimes not, depended on the budget. These motors got beat on HARD!!!! 15-20 minutes at 4-6K, 5 or 6 heats a night on the weekends. My point is, with proper cooling system, and sane driving, a 400 will last just fine. No, it will not rrev like a 350, but it doesn't have to. Build a stock 400 shortblock with quality components and put the money into the heads. Don't get a 4 bolt main 400 block, there is actually LESS metal down in the mains than the 2 bolt. The 400 was built as a lower rpm torque motor. Isn't that what we want ?????
 
The problem with 400 blocks is that GM had to siamese the cylinder walls to make that big bore fit into the block. This means that coolant can't fully surround the cylinders, so cooling is incomplete. The design doesn't inherently make the engine run hotter. The problem comes when the engine gets overheated for some reason. Once overheated, the siamesed area of the cylinders gets much hotter than the rest of the cylinder wall. Oil starts coking from the heat, sticking the piston rings. At that point the engine can become damaged to the point that it will need to be rebuilt. :(

Neglectful owners cause most of the problems with 400's however. They got a bad rep many years after they were sold. As the trucks aged, the radiators got clogged and crusty, yet the owners kept towing heavy trailers, etc. What would be an overheating problem with other engines could end up being fatal for a 400. That gave the 400's a bad reputation, when really the owners should have been the ones that got a bad reputation. :wink1:

A cooling system that's in good working order is 100% madatory on a 400. Running a good synthetic oil is also helpful, as it is far less likely to coke in the event that the engine does overheat.
 
Hey guys thanks for the information.
I am just struggling a little with this decision.
I just keep remembering the old saying, "there is no replacement for displacement".
The suburban just seems like too big of a vehicle for only a 350 a 400 just seems like a much better choice to start with.

And having this be a daily driver and emissioned really ties my hands.

So just to sum this up what kind of power are we really talking about on these engines:
My stock 91 350
a 355 with TBI compatible and streetable heads and cam
a 383 with TBI compatible and streetable heads and cam
a 400 with TBI compatible and streetable heads and cam

Thanks

Tim
 
Just remember that if you choose to go 383 or 400 you will need to have a new chip burnt for the application otherwise the timing and fuel curves will be incorrect.
 
A 406ci with about 10:1 compression and heads that can flow somewhere around 270/280cfm should get you darn near +/- 400HP/500TQ in street trim.

383's and 400's make torque! The bigger stroke isn't going to want to rev up unless you build it with a light rotating assembly. The 350 on the other hand, with it's 3.48' stroke will rev like a mofo. But then you'll need to start worrying about valve float and all the other problems associated with high RPM operation.

There's a fine line between building a strong street engine and race engine.

I really like the AFR heads. They are quite pricey but there performance is undeniable. Look for heads that have an intake runner size around 180-190cfm and flow well.

Here's a Link to my old website. You can find flow sheets,dyno charts and who knows whatelse there.

KM
 
tch777 said:
So just to sum this up what kind of power are we really talking about on these engines:
My stock 91 350
a 355 with TBI compatible and streetable heads and cam
a 383 with TBI compatible and streetable heads and cam
a 400 with TBI compatible and streetable heads and cam

Thanks

Tim
Click to expand...
If you're trying to keep the TBI setup, consider 330-350 the mildly affordable maximum HP.
Travis
 
TravisO said:
If you're trying to keep the TBI setup, consider 330-350 the mildly affordable maximum HP.
Travis
Click to expand...

i am running that setup and wish i would have gone with edelbrock mpfi... only 200 more than my tbi setup but i can burn my own fuel maps.


Even if you stick with the trusty 355 you'll need to modify the fuel/ignition map if you want to hit anything above 300 hp.

You can get up past 400 hp with tbi but it would take some good heads and alot of computer tuning. First thing you need is a bigger tbi and manifold. I went the with the holley setup... projection manifold, and 670cfm tbi. I was gonna go with a 454 tbi and a bored stock manifold but the holley manifold flows ALOT better.
 
its all about what you want it to do!

400's are good motors just as harry h3 said, it was usually the owners fault..i have 2 rigs, 1 i play around in and 1 i compete in and the motors are completly different close to same power but completly different

you need to decide what you want the motor to do before you try to figure out how to build it..i think people under estimate the 377 way to much, which is 350 crank in 400 block big piston short throw, but depends on what you want the motor to do

in my play rig..its a 383..via the 350 block with a steel aftermarket crank made for a 383 with the 6" rods...because the longer rod equals more torque, same principal as putting a cheater pipe on a wrench for leverage..to keep wrist pin out of oil rings i used a 327 piston..and it has aluminum vortec fast burn heads...these heads accept either vortec or old style intake and also centerbolt or perimeter bolt valve covers..Intake port volume is 210cc and have raised runners .024" higher than stock..wish they would make these in cast..then they would b in my bogger...i also run the gm performance intake for a carb! heads and intake are gasket matched and ported and polished...its around 450hp i would say and about the same if not more torque

where as this one has about 450 hp but around 300-350 ft lbs torque
in the comp truck tho you see i run in stock class, but you can get by with quite abit as long as it all cast iron and looks stock on the outside even have to run a cast iron intake which i run a older('70) camaro hi rise...it has a large journal 327 or 307 crank in a 400 block.with even longer rods (titanium rods)..there for, it has a 4.185 bore with the 327's very short stroke(3.25") for the fast rev to get tires rippin...but like i said the engine is built for what the truck does and this 1 screams down a 3-4' deep pit 120' long...i'm actually

looking 4 302 to put in the 400 block...talk about rev like a die grinder..man o man..i cant run the vortecs because of the center bolt valve cover give me away,,,so i run part #14011034 heads any1 have a 302 crank they would get rid of or a newer model 265 with the 3" stroke
 
blazin_blazer said:
in my play rig..its a 383..via the 350 block with a steel aftermarket crank made for a 383 with the 6" rods...because the longer rod equals more torque, same principal as putting a cheater pipe on a wrench for leverage..
Click to expand...

actually its the other way around... 5.7 rods give you better tq, 6.0" give you better hp and higher rpms. Has to do with the rod ratio. Stroke is what the cheater bar theory applies to.
 
actually, you're wrong on one part. while a 6" rod does allow for better upper rpm power, due to the piston dwelling at TDC longer, giving a more complete burn, the 6" rods also provide more leverage on the crank journal, allowing more of the force from the piston traveling to BDC to be fed to the crank.

as for 400hp with a stock TBI, or any out of the box TBI, dream on. TurboCity modifies throttle bodies that *could* get you to 400 hp, but having the injectors still hanging above the throttle bores really hurts power. the Holley manifold is a step over stock,yes. but you would have had better results with a carbed application intake and a TBI adapter.
 
i wasn't going to argue

but the longer rod is the cheater bar theory, i'm glad some1 else stepped in, glad i toke him off of ignore also!
 
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