[CandiMan]

Hello everyone

I'm familiar with engine rebuild and repair, from heavy duty diesel engines to 4cyl gasoline engines (I've never worked on a Wankel) For the most part, rebuilding the short block on a piston engine is the same regardless if it's a gas or diesel. When it comes to the SBC I'm slightly clueless. I know some of the basics like the different CID for the SBC and 2 or 4 bolt mains.
I'm currently driving a 91 S10 and as you guys know, dropping a SBC between the frame rails is a common mod. Some have even squeezed a BBC in between the S10 rails. Besides the usual intake and exhaust bolt on mods, all my other vehicles has gotten chassis/suspension and brake mods.
When considering your first SBC build, what are some items to consider? With that being said, let me throw some questions out there.

• Are all SBC short blocks externally the same? Same bolt holes, same bolt pattern, etc?
• Does the 400 CID motor have more capability and potential compared to the stroker 383?
• Which one has more aftermarket support, 383 or 400?
• If you’re planning on changing the rods and pistons to accommodate your HP goal, does it matter which SBC short block you get from the salvage yard?
• Are there certain year/model SBC short blocks better than others?
• Does one block have more nickel content in the metal compared to others?
• If you're considering a 383, does it matter which 350 short block you get from the salvage yard?
• Pertaining to the above question, would it matter which short block you get from the salvage yard if you choose to achieve your 383 with a aftermarket crank, rod and piston kit or if you choose to use a 400 CID crank?

It would be nice to know I can go to a salvage yard and pick any SBC short block while knowing that after I rebuild it with all the internal good stuff, I can then choose a cam/heads and everything will bolt up with no problem to complete my long block.

[DoubleVision]

In order of your questions.
1. Just about, they changed little from 1955 to 1985. In 1968 the crank journals went from small to mediums for added strenth. in 1986 they went to center bolt valve covers and a 1 piece rear main seal. some 400 small blocks have 3 freeze plugs on the side instead of 2. Other 400`s have 2 with a hump between the 2. The 400 was the only small block to use shorter 5.565 connecting rods. It`s also the only small block to have steam holes in the block and heads deck.
2. Yes. I`ll take a 400 over a 383 any day.
3. Pretty tight race, as they are both popular, 400`s are hard to come by so the 383 is more popular.
4. Not really, as long as it`s not a pre 1968 block. any smogger 350 block from the late 60`s to the late 90`s will work.
5. In my opinion, yes. I always find 1 piece rear main seal with factory roller cam blocks. the 1 piece rear main seal isn`t prone to leak like the 2 piece design. And a roller cam beats a flat tappet cam hands down.
6. They make stroker crank kits for both 1 and 2 piece main seal blocks. If you use a factory 400 crank the mains will have to be ground to the 350`s main bearing size. Next during the mock up assembly, no matter what crank you use aftermarket or stock 400, you`ll still have to check for contact and grind where needed. It`s common for aftermarket cranks and rods to be clearenced so sometimes grinding is not needed, but it still must be checked.
Depending on what you plan to use, a flat tappet or OEM roller cam, you can find any 350 engine in the yard and come out okay. Keep in mind there is a balance difference between 1 and 2 piece seal cranks on the flywheel end.

[oldbogie]

Many good blocks, one of the easiest to find is 3970010, its a frequently used heavy duty 4 inch bore block seen from the original 302, Z28, Camaro's thru heavy duty trucks. Will come in 2 or 4 bolt versions. The 2 bolts are mostly in 1/2 ton trucks and the 4 bolts in 3/4 ton and up. But many 1/2 tonners especially the Heavy Half model have them. The only way to tell is to pull the pan and count noses.

I recommed a 350 built to 383 or more over a 400 as finding 400s is a rare occurance anymore. So rare I don't even bother.

Bogie

[CandiMan]

I was at the salvage yard yesterday trying to find some interior trim pieces for a vehicle I'm working on. While there, I decided to pop the hoods on any 70's Chevy truck. I came across two trucks with the engine still intack, so I took a few pics with the cell phone. Ultimately I know checking the engine code is the sure way to go in determining which engines the trucks has, but I was curious to know if you guys might know which engines these are by looking. I know it's a long shot so bare with me. Both trucks were the early 70's.

[CandiMan]

How about a 73 Cadi with a 472ci

[crussell85]

i built a 383 last summer using a 350 block from a 1994 k1500. I used the scat 4340 cap screw rods with arp 12 point bolts and did not have to clearance the block which was a bonus to me not having to grind away at my block. I would try to stay with a 1 piece rear main they are less prone to leak. I think if you have or can find a good 400 block build that but it is hard to find a good one. That is why the 383 is so popular, besides you have a lot of the parts from your old 350. The 383 would also be a little faster off the line than the 400 if built the same. Good luck and have fun!

[curtis73]

Originally Posted by CandiMan

• Are all SBC short blocks externally the same? Same bolt holes, same bolt pattern, etc?

Pretty much. Some of the muscle cars that didn't have anything but an alternator didn't have accessory bolt holes in the heads, but I doubt you'll encounter those in a normal boneyard. But for the most part, they're all the same. You could bolt on the accessory drive from a 283 onto a 1999 smallblock.

• Does the 400 CID motor have more capability and potential compared to the stroker 383?

cubes are cubes. The more you have, the more power you can make without losing all your low end. The 383 has 4.030" bores, the 400 has 4.125" bores. No contest in my opinion. Same external block, same stroke, bigger slugs.

• Which one has more aftermarket support, 383 or 400?

They're both pretty much the same in the aftermarket. The 383 (since its a more common build and is based on 350 bores) has a few more piston options. If you're sticking with factory stuff, the only thing lacking in the 400 world are factory heads that flow enough and provide a logical compression ratio. 400s need a bit bigger chamber (or dished pistons) to get a logical CR, and nearly all of the factory options of larger chambered heads are really crappy. Vortec heads are the best-flowing factory head, and they make a REALLY nice 400 if you plan on keeping it below 5500 rpm. But other than that, they only differ in main size and piston size. All SBC parts will otherwise interchange. 400s (as has been mentioned) have extra coolant holes drilled in the decks, but you can simply drill any SBC head to match up with that passage.

• If you’re planning on changing the rods and pistons to accommodate your HP goal, does it matter which SBC short block you get from the salvage yard?

Other than your target HP goals, no. 2-bolts will handle a very stout output, but some like to hold out for a 4-bolt. Avoid the 305 or other small bore engines as they are often times very thin castings, and they can't be bored up to 4". The "010" block is common, often its 4-bolt, and its a plenty beefy 4" bore block. Most of the 400s are very similar, and I'm not up on their casting numbers so I'll not try to speak intelligently about them

• Are there certain year/model SBC short blocks better than others?

I prefer late-model blocks because they are already cast as roller-cam blocks. 87-up in cars and some trucks (hit or miss) and 96-up will all be roller blocks. They are also 1-piece rear mains. You're slightly less likely to find cheap plentiful parts in the junkyard. By slightly, I mean that you'll actually have to lift some hoods instead of randomly tripping over them in the dirt like you would older SBC parts.

• Does one block have more nickel content in the metal compared to others?

Big can of worms there For years it was thought that blocks with 010 and 020 cast on the side near the freeze plugs meant it was a high nickel block. The common belief was that meant .1% nickel and .2% tin. The nickel made it hard, and the tin helped it flow into the molds better. However, according to a discussion on another forum with a GM foundry worker, that is not true. The side numbers simply identify the side core used to cast that block. The actual alloy varied in every crucible. High nickel is also not necessarily a benefit. Its harder, but harder does not equal stronger. Harder does mean it won't absorb harmonics as well, which means it may not be best for high-rpm engines. Read up on it here: http://maps.google.com/maps?f=q&sour...38624&t=h&z=15

• If you're considering a 383, does it matter which 350 short block you get from the salvage yard?

I do know that every block has subtle differences in the pan rail and the bottom of the water jacket. If you have to clearance the pan rail to get the crank to fit, some will either A) have more room = less grinding, and others have B) more meat in that area meaning you'll have more room to grind before you hit water. Again, I don't know which ones are better, but suffice it to say that they'll all swallow a 3.75" crank with very minimal headache.

• Pertaining to the above question, would it matter which short block you get from the salvage yard if you choose to achieve your 383 with a aftermarket crank, rod and piston kit or if you choose to use a 400 CID crank?

A 350 block has smaller main journals than 400s. A 383 stroker crank is sold at having either 400 mains or 350 mains. Putting a 400 crank in a 350 block to make a 383 requires turning down the crank journals to fit the smaller mains in the 350 block. BUT, with the huge proliferation of cheap stroker cranks on the market, you can probably buy an aftermarket stroker crank for the cost of buying and modifying a stock 400 crank. I bought a forged stroker crank for my LT1 for $350. Cast cranks can be found for $150-180

Another thing to consider, most SBC rods before about 92 are forged, so they'll take some abuse if you properly prep them. After 92 many of them were "pink" rods which was a powdered metal casting that also does very well. Depending on your power goals, you might be able to do a basic reman on the shortblock and then pick your heads and cam. I've run 450 hp on a stock shortblock 2-bolt and I didn't lose any sleep over it.

Sounds like you're doing it right; researching and putting together the best individual components for the job. If I were doing it, I would personally do this: Buy a 96-99 Vortec longblock for $500. Sell the heads for $300 if you're not going to use them. Cast stroker crank for $180, stock rods, aftermarket pistons, pick cam and heads and have fun. If I were doing a 400, I would buy one and do the same, the only difference is that you can usually pick them up for cheaper but the heads are worthless

Either way, similar investment. You can get 400 cubes with a 2-piece rear main and flat tappet cam, or a 383 with 1-piece rear and a roller cam. Although cubes are king, a 383 roller can make similar power and torque compared to a flat 400, so I guess its up to the end used to decide. If you want the best of both, do the 400 with a retro-roller conversion... but you need to open the big wallet for that one.

[DoubleVision]

Those both look like Olds engines Candi. Neither is a SBC.

[ericnova72]

Originally Posted by crussell85

. The 383 would also be a little faster off the line than the 400 if built the same.

This is completely false. Crussel, where did you get this erroneous information?
Built with the same parts, the larger engine will always make more power.

[Deez]

If you find a good 400 by all means use it and make it bigger. Now the Crussell85 thing, look man, he has a 383, so of course his is going to be faster. Do you really think he's going to say his is slower? LOL

Here, do like this. Say you were to stroke either/or and each made 1.25HP/CI. The 383 would make just under 480. Stroke a 400 to 420 and it would make 525 at the same 1.25HP/CI. 50HP via displacement looking at it like that. TQ would also be abundant.

[ssmonty]

Some of the later blocks have to be modified to be able to use a mechanical fuel pump.
ssmonty

[MrChevyDC3]

Originally Posted by curtis73

If you want the best of both, do the 400 with a retro-roller conversion... but you need to open the big wallet for that one.

Hey, I was told by my builder that this is the route that I"m going with my 408 build. So i'm doing my research on builds using the 400 block. A lot of this info was VERY useful. So does the cam selection alone make it a "retro-roller"???

[crussell85]

if a 383 and a four hundred are built the same in the top end and put in the exact same vehicle I guarantee the 383 will take off faster than the 400. The 400 is still gonna smoke it after it catches up to it. I am not saying that the 383 will blow the 400 off the line but it will take the 400 off the line. The 383 has a longer stroke than the 400 which is gonna give it the torque over the 400 off the line. I am not talking about a 383 stroker vs. a 400 stroker. I am saying a stroked 350 to a 383 against a stock 400 rotating assembly. Sure the 400 is bigger cubic inches but it makes the bigger cubes in the bore and not the stroke.

[cobalt327]

Originally Posted by crussell85

The 383 has a longer stroke than the 400 which is gonna give it the torque over the 400 off the line.

I suggest you check your facts. The strokes are the same- 3.75".

The bores are different- nominally 4" for the 350 block, 4.125" for the 400 block.

Don't bet against the 400. lol

[ericnova72]

Cobalt, right on!

Crussel85, thats the 400 crank you are using to build your 383, you know. They just grind the mains to the smaller 350 size, and that's exactly how it was done long before the aftermarket started making them already sized to fit the 350 block.

Built my first 383 back in 1987, when you still had to get the mains turned down .200" on a 400 crank to build one, and people still used the short 400 rod. Using the 5.7 rod was unheard of, you couldn't get pistons. That engine is still alive today, runs 11.60's in the 1/4 in a '79 Monte Carlo street/strip, was just freshened with rings, bearings, gaskets 2 years ago with about 55,000 miles on it. No noticable bore wear with forged pistons and moly rings, but it is never run in cold weather.