[Chevy71]

I am looking for a good motor for pulling and with lots of torque which would be my best bet?

[OddRodder]

I would go with the 383, not because it will make more torque but, because heavy towing-pulling tends to stress an engine and could lead to cooling problems. The 383 is easier to keep cool when compared to the 400 because the 400 has siamezed cylinders!

[smallblockhead]

I have ta go with the 400, with more cubes you can keep the RPM down a little while still keeping the torque up and thats what makes a puller. Plus the 400 has larger main journals - less main stress per squ. in of bearing

[ronb]

383 a real stump puller!

[nickel333]

400's over heat and the main webbing is weak. id go 383 because the 350 block stays cooler and has a stronger foundation. But if your in a huge need for 17 more cubic inches at the expense of strength and cooling problems go 400.

[stonedchihuahua]

Nickel when have you seen a 400 overheat??? What about someone blow one up... An engine will only last to how you build it...

both are good engines but no matter what you get make sure your cooling system can handle it...

the 383 will probably be cheaper to build since in most areas 350 blocks are a dime a dozen.. also the kits for these things seem to be more and more popular.. meaning in SOME cases the pistons and such are easily purchased in a kit at a cheaper price

also you shouldn't have any problems with braking mains or the main webbing but if you wanna be able to rev the thing (for whatever reason) then make sure you have 4 bolt mains and studs...

neither one should have much of a milage advantage as long as you carb both of them properly they will have the power you want and will be alright on gas

umm also the 17 cubic inches aren't the only difference between the two engines

a 383 has a bore of 4.030 while the 400 is at 4.125 inches possible 4.155 inches if you rebuilt it... since they both have the same stroke it may not matter but having a wider bore to increase displacement is usually preferred to increasing the stroke because having a bigger stroke means that your rods are going to be moving alot faster having more stress put on them because of the extra distance they must travel in the same amount of time...

I'm not saying either engine is superior I am just saying there are advantages to both

[nickel333]

stoned...both have a 3.75" stroke so the "rod speed" is going to be the same right? the pistons and rods are going to travel the same distance, the only difference is in the bores, 4.030 to 4.125. And yes the bigger bore in my opinion is allways better for power{why wouldnt it be??} Now as far as me actually seeing one over heat i havent seen one personally. ive heard this on more than several occasions and its a well known fact. Its probably why they quit produceing them. {just guessing there} i simply stated my opinion based on what ive heard over and over again about 400's. Now the reason i chose 383 for him was because of expense to build {finding a 400 block is next to impossible} and potential reliability. What bad stuff have you heard about a 383. And dont tell me youve never heard 400's are notorious for overheating yeah theres allways an exception. but theres nothing thats going to cause a motor to overheat like towing.

[ February 05, 2003: Message edited by: nickel333 ]</p>

[lancerx]

Just completed over 100 dyno pulls on my street 406
small block, makes 405 Hp and 490 ft/lbs torque peak. I would recomment a 383 based upon the 350
block because it cools better, a 400 block will cook the rings if overheated, and the 5.7 rod used with most 383's is better than the 5.65 rod used in the 400, you can put 5.7 rods in a 400 but the cooling issue is not resolve. You can also buy after market blocks that will resolve some of the 400 block inherent problems but how much do you want to spend.
Big blocks make even more power, so do 500 CID caddy's.

[F-1Rodder]

I drive a hot 383 and although I have always wanted to build a 406, the cost would be much higher for very little return in power. The 400 cooling scare is an actual one, but remember they built them stock and they cooled just fine. Rodders tend to put the 400 in behind small radiators without shrouds and complain that they get hot idling through traffice on the way to a car show....go figure! I think the real issue is just the cost.

[85 regal]

just curious lancerx why cant you put the 5.7 rods in a 400sbc .a friend of mine did explain that one. now you may have to do some cleance grinding for the rods depending on the cam you use . just my $.02

[stonedchihuahua]

Yeah I have heard many people say 400s overheat and every single person I have asked if they have seen it said no which leads me to believe alot of it is just BS as far as gm stopping production because of that I don't quite think that was it... Gm probably wouldn't have put something into production that never cooled properly... It was an emissions thing... they cut down alot on high displacement engines and must have figured it was cheaper to produce poor flowing 454s instead...

Also yes I did state that the 383 has the same stroke... I think i did at least... It is going to have the same rod speed but I have heard (do not take me to heart on this) of people having problems with their 383s with some strength issues (then again there are dumbasses who break all kinds of things)

Like I said they are both very good engines and it is probably going to come down to cost.

[70_Chevy_El_Camino]

The only Problem I have found with 400 SB Chevy's is the shorter rod causing more outer cylinder wall wear making the cylinders out of round and causing more heat, but to correct the problem go with 5.7 rods and get the corrected pistons to go with the new rod lenght, if i had my chouce between a stroked 350 or a 400, Ide choose the 400 any day especially after correcting the thrust to wall ratio

Originally posted by nickel333
stoned...both have a 3.75" stroke so the "rod speed" is going to be the same right? the pistons and rods are going to travel the same distance, the only difference is in the bores, 4.030 to 4.125. And yes the bigger bore in my opinion is allways better for power{why wouldnt it be??} Now as far as me actually seeing one over heat i havent seen one personally. ive heard this on more than several occasions and its a well known fact. Its probably why they quit produceing them. {just guessing there} i simply stated my opinion based on what ive heard over and over again about 400's. Now the reason i chose 383 for him was because of expense to build {finding a 400 block is next to impossible} and potential reliability. What bad stuff have you heard about a 383. And dont tell me youve never heard 400's are notorious for overheating yeah theres allways an exception. but theres nothing thats going to cause a motor to overheat like towing.

[ February 05, 2003: Message edited by: nickel333 ]</p>

dont forget that the 400's have shorter rods than the 350, but you can convert the 400 to a longer rod which reduces friction which reduces heat, 400's are great motors, i have one that is .060 over with flat top SRP pistons and 5.7 rods i got a griffen aluminum radiator and run a 160 thermostat and add a lil water wetter from redline performance prouducts i rarely see temps over 190 during the summer in city driving

Originally posted by 85 regal
just curious lancerx why cant you put the 5.7 rods in a 400sbc .a friend of mine did explain that one. now you may have to do some cleance grinding for the rods depending on the cam you use . just my $.02

You need to put a small base circle cam in a 400 when you do the 5.7 rod convertion

[GTO 1965]

The 400 sbc has steam ports between the cylinders to help with cooling when the engine is operated under 3500 rpms, when people put heads from anyother engine ie. 882, 186, 041 etc. on them they need to drill the holes in the heads to matck the block and also use the correct head gaskets too.

Jim