Hot Rod Forum banner

What's the better motor?

  • 400 SBC

    Votes: 216 45.7%
  • 383 SBC

    Votes: 161 34.0%
  • Bore your 383, get a 388

    Votes: 22 4.7%
  • They're equally good street motors

    Votes: 74 15.6%

Ok, here's the debate of the century: 383 or 400 chevy!! Cast your vote and reason

227K views 299 replies 138 participants last post by  Studebaker 
#1 ·
OK, in the opinion of everybody here, what is the better street motor, a 383 or a 400? Take into account the strength of the motor, availability of parts, reliability and power.

I'm torn, I have a 388 and i guess its nice to have the availability of 350 parts and the better cooling at virtually no sacrifice in power.

What do yall think?

K
 
#2 ·
I guess all that matters is which block you happen have on hand. 400s tend to unshroud the valves a little more than 383s for a few extra hp, not to mention the extra cubes. 383s don't have the cooling issues though. A toss up I guess. What's layin' on the floor is what get's built as far as I'm concerned.
 
#3 ·
Re: Ok, here's the debate of the century: 383 or 400 chevy!! Cast your vote and reason

killerformula said:
OK, in the opinion of everybody here, what is the better street motor, a 383 or a 400? Take into account the strength of the motor, availability of parts, reliability and power.

I'm torn, I have a 388 and i guess its nice to have the availability of 350 parts and the better cooling at virtually no sacrifice in power.

What do yall think?

K
With all of my posts written on the subject you already know what I think.

coldknock said:
I guess all that matters is which block you happen have on hand. 400s tend to unshroud the valves a little more than 383s for a few extra hp, not to mention the extra cubes. 383s don't have the cooling issues though. A toss up I guess. What's layin' on the floor is what get's built as far as I'm concerned.
If you use the Fel-Pro gasket #1014, there are no cooling issues with a 400.
 
#6 ·
#7 ·
I went with a 400 because a buddy of mine gave me a core for free. Turns of the core was no good. I would have built a 383 if I couldn't find a 400 block. It was either a 383 or 400 but definitely not a 350. I like the extra displacement of the 400. My engine dynoed at 425hp/470 lbft torque. With a 160 t-stat, on an average summer day in the high 70's low 80's it runs 170-180 degrees, 190 in traffic. I have a 3 core rad. My 350 on the other hand ran 200-210 in traffic and on the highway on a hot day 205 with the same cooling system. It all boils (pun intended) down on the machine work and clearances. If I had to do it over again I'd stick with the 400.
 
#10 ·
My vote goes to the 400

Years ago I built or was involved in building several SBC�s (305s, 327s, 350s, 383s, 400) only one of them was a 400 which was the last and best, the 400 was built after researching and putting aside the bad reputation it had.
Now 20 years later I am back to building another SBC, I did my research and choose to build another 400, more bang for the buck.

The issues the 400 have are basic and very easy to over come (keep in mind the 383 also has it�s unique issues). 1) It is a SBC with a 4.125 bore so you are limited to how far you can bore it out, 2) It is a bigger displacement motor and creates more HP and heat, it will need a bigger radiator, 3) The design of the block (so we can have more cubic inches) requires steam holes, so use the correct head gasket with steam holes and drill the steam holes in the heads.
Take care of these issues and a 406 will run just as well as a 383, but when you stomp the gas pedal you will feel the extra cubic inches the 406 has.

400 Pro�s
No if and or buts there is NO replacement for displacement:
350, .30 over, 3.75 stroke = 383 CI.
400, .30 over, 3.75 stroke = 406 CI.

It cost about the same to build a 406 or 383.

You can put a slightly bigger cam (more HP and Torque) in the 400 and maintain a good idle.

400 Con�s
The 400 blocks are getting hard to come by, but they are out there.

Weak main webbing, this is not a problem unless you are building a wild racing motor.

DISCLAIMER: I am no expert my statements are based on my personal research and experiences, I have NO problem with some one giving constructive criticism, I don�t mind learning even if I�m wrong, so lets hear it.
Both the 383 and 406 are awesome motors and almost anyone is going to be happy with ether one, if you have a 350 block sitting in your garage build a 383, if you have a 400 block build a 406, it�s that simple.

406chevelle
 
#11 ·
I would have to say 400 for the reasons that have already been stated. As long as you dont bore them too far, and you have a good fan and radiator, there shoulden't be any cooling issues. Like stated before, with a 400, the bigger bore allows the heads to flow better plus you get more cubic inches. As far as strength of the block goes, I know of people running 2 bolt 400s (splayed mains though) in IMCAs, and from what I have seen the blocks hold up pretty well, and those motors are reving to 7500-8000 RPM.

Adam
 
#12 ·
That's basically what I was going to put in the poll but forgot. Basically its just an availability of parts. If you have the parts to build a 383 its probably not worth it to go hunting down a 400 block. For me its nice to have the safety of the 388. I was lucky to get a really nice 350 block (heavy casting four bolt). Definately though, my next small block will be a 406 or a step further to a stroker. That's another point that hasn't been brought up, stroking. The 383 is at its potential limit, whereas the 400 can be stroked all the way to 434 or further.

So there u have it, build whatever parts are in your garage!

K:thumbup:
 
#18 ·
For power, it's hard to beat the bigger bore of the 400"!!

Properly done, with a good cooling system - there shouldn't be any 'cooling issues'!!:thumbup:

If I was going to build a 350 based stroker though, it would be a late model hyd. roller block w/one pc. rear seal. You can build a 383" for similar money as a 350". For a bit more, you can go with a 396" SB.

Personally, I think the factory roller setup with a performance hyd. roller cam is more of a 'selling point' than the bigger bore of the 400". At least, for anything other than an all-out race engine!!

Single biggest 'negative' for the 400" factory blocks, has to be the thin cylinder walls.
 
#19 ·
the heat has to be uneven in a 400 block, causing (probably, just speculation here) uneven wear. There are no roller 400 blocks (not that big of a deal I guess, you could retrofit for some extra $). I guess its always been told to me to stay away from them because they simply have less cooling passages than a 350 block and thinner walls. I've also "heard" that they blow head-gaskets more easily. Anybody have details on this?

K:thumbup:
 
#20 ·
killerformula said:
the heat has to be uneven in a 400 block, causing (probably, just speculation here) uneven wear. There are no roller 400 blocks (not that big of a deal I guess, you could retrofit for some extra $). I guess its always been told to me to stay away from them because they simply have less cooling passages than a 350 block and thinner walls. I've also "heard" that they blow head-gaskets more easily. Anybody have details on this?

K:thumbup:
Never seen uneven wear be a problem or heard of it for that matter. The 400's don't have less cooling passages to my knowledge, just no room between the cylinders. I am also not certain that the walls are thinner than all 350s. The cylinders are simesed to allow a decent wall thickness. It would be interesting if anyone out there has sonic tested them to know for sure. The old wives tales are not always real accurate. I have never had any problem keeping my 400 cool on the street. I dont even have a wonderful cooling system. I think that is also a wives tale.

Chris
 
#21 ·
Ya turbo s10 I think you hit the nail on the head there are alot of old wives tails that float about for the 400sb. It is true that the 400's don't have very thick cylinder walls but the same can be said for alot of the later 350 castings and especially the 305 castings. This in its self isn't really to much for a problem unless you are planing a large over bore. As for the head gasket sealing trouble I don't think that would be anything to worry about, even if it was true with modern head head gasket technology. The siamesed cylinder have been used in other engines to very successfully I might mention.
 
#23 ·
scott011422 said:
You couldn't give me a 400.................. Not to mention finding heads with that damn steam hole............
Something tells me that is because you have never had one. Oh and "that damn steam hole" you mentioned is actually a pair.

Tell you what if anyone ever trys you can give me a call and I will get the junk off your hands.
 
#25 ·
2 Cents

I have to go with the 383.
Bottom end of the 400 has always had problems with weak structure. Out of 10 blown 400's, 8 will be because of problems with the mains and / or crank. Yup, today you can buy a better crank. The variety of parts available for the 400 are very limited. In the last two - three years it has gotten better but not as good a selection as the 383. There is no replacement for displacement, except maybe RPM. 400 balance is a must and 383 balance is desirable. Harder to find blocks? How many do you want? I cheat, I get mine down in Mexico.
Both are good engines but I need to travel between CA & WI. I donut go to the strip anymore. I need the 383. Well hey, that is 2 cents from a guy that only builds 383s from 350 / 4 bolts.

hr41pearl :cool:
 
#26 ·
Over heating on a 400 is a wives tale.
If I have to explain it you wouldn't understand.
If the motor is built correctly and the chassis is setup for cooling there is no problem except for the ones that don't take any advise.
What head gasket problem ? Maybe the dummys that reuse head gaskets. :D
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top