karkrafter

Have you found a source for a small journal stroker crank? I've looked but so far haven't found one.

DZAUTO

No.

But basically, there are 2 options here.
1. Have the mains turned down on a stroker crank (with 2.45 mains) to fit the small journal block (which has 2.30 mains).

2. Have the small journal block line bored for a 2.45 main crank (my personal preference).

In my opinion, the following is VERY IMPORTANT for ANY small journal block (265-283-327).
Up through the 68 blocks, the hole threads for main cap bolts began right at the web surface. In 69, the threads began about 1/4in BELOW the surface. A good machine shop can cut out the upper 2-3 threads so that the threads begin about 1/4in down in the hole.

WHY?
This changes the stresses in the main webbing and moves the area of stresses deeper into the main webbing for greater strength. Of course, when having this done, it is necessary to use the longer 350 style main bolts (or studs if you prefer).
The difference in stresses in the main webbing are illustrated below.

TCracingCA

I used to beat all of the 383 Mopars, and the 440s with a SBC, but thought I would look up the best of the GM sold ZZ383s

Ok Steel 4340 crank good!!!!
The heads-Fast Burn are about a 235 flow head and I am up near 280cfms!
Max RPM is 6000 (425hp @5400/449lb ft@4500). I set my rev limiter at 7800!
Hypereutectic Pistons 9.6 CR 62 chambers
222/230 duration roller 509/528 lift
Externally balanced
32 degrees total advance 770cfm carb
92 Octane

Part #12498772

Overall not a bad engine, but I would eat it for lunch, but to be fair, I have 20k plus street/race engines!

Ok rebuilding ZZ350, the best sold is the Fast Burn 385 Turn key
Part #19201331
385hp @5600/ 385lb @ 4000

5800 redline, they put the same head on as the 383 above!
The cam is 208/221 duration, 474/510 lift

Everything else basically the same as the 383! Same block, same rods, same pistons, same compression ratio, same 92 octane, same timing, same valves!
Different rockers- 383 has rollers, the other stamped steel.

You do get a Flexplate bolted on, so for a Manual Crashbox you need to buy the External balance flywheel.

For 33 extra cubes, you pick up 40 horsepower over a top of the line ZZ 350/385. You pickup 70 hp over the base ZZ350/355

Randy G.

I know I've posted this a dozen times before. I put a Blueprint 383 long block in my '62 almost 2 years ago. I put a Bowtie Overdrives 700R4 behind it. Dyno sheets said 435 hp with 469 ft lbs of torque. Roller hydraulic cam and Comp roller lifters means no special oil required. It has a one piece rear main seal since they use later blocks, and has absolutely no leaks. It runs great and really pulls hard.

I bought it from Summit before the slight price increase for just under $3,900 delivered to my door, warranty and dyno sheets included. I put an Edelbrock carb and an Edelbrock manifold on it with the stock distributor. I'm so confident in it I would drive it to New Jersey in back tomorrow if I had to.

karkrafter

I don't think you can get that one anymore but when you could it was over $7000!!


I've seen one MAJOR builder [can't mention name because it's not a sponsor] who has same performance for $4500 carb to oil pan inc. ignition. All new parts including new GM block...dyno tuned and broke in as well...

GTOguy

I'll add this: I've been a big block guy all my life, and am used to big inch, stump pulling engines. My GTO's always gave me that kind of rush. Driven and worked on many stock displacement SBC's, and they always ran well, and were very durable, but didn't have that gut wrenching, neck snapping pull of a big inch motor. Then I drove a 383 stroker....It truly is a magic combo. I don't know of a single person who regrets going to a 383 after they've done it. They do everything well, and look right in these cars.

karkrafter

Lemme ask a question of all the engine guys, If OP or anybody else, had decided to build a 383 from scratch....should he at least make a cursory search for a sbc 400 as a core first? I mean, why give the extra 20 cubes away right? You replacing all the same parts as a 350 build [if you can keep it under 5500 PPM you can even use the original crank..] and the only reason 383's exist is because of the rarity of the 400 blocks[but they are still out there, I think I know where 3 are right now. ]

MikeM

You're not counting my three, are you?

TCracingCA

The stroke is out to 3.75 and the bore is 4.125. You would have to sleeve it down and those ran cast cranks which is Ok for lower hp RPM and stump pulling!

I do like thst GM 4340 steel crank, and would have to clearance I assume rods to the cam clearance.

karkrafter

no no no,

I mean build a 406 instead of a 383. Use the stock 400 crank [so you don't have to clearance anything], nothing special 5.7 rods, new pistons, and everything else.

Not counting the cost of either core, 406 is cheaper and will have more torque...assuming you can find a 400 core [and it's final purpose is a street engine] 23 more cubes, less money.

65air_coupe

I drank DZAUTO's Koolaid and went looking for 400 blocks myself. Stopped by a friend's shop that's a local mechanic and also a circle track racer and asked him if he ever saw any more 400 blocks around. He gestured to a corner of his shop and said there's 3 over there..."you want one?" Cost me $100! Had it boiled out, magnafluxed, bored, new cam bearings, brass freeze plugs plus tapped a couple holes in the lifter valley so I could use OEM roller cam components. That cost $550.

As you said, the rolling assembly prices are practically the same so why not? There are some that believe there's a cooling problem with 400s but that's been proven false as long as you use the correct head gaskets.

troutster71

[QUOTE=karkrafter;1594987095]no no no,

I mean build a 406 instead of a 383. Use the stock 400 crank [so you don't have to clearance anything], nothing special 5.7 rods, new pistons, and everything else.

Not counting the cost of either core, 406 is cheaper and will have more torque...assuming you can find a 400 core [and it's final purpose is a street engine] 23 more cubes, less money.[/QUOT]

It sounds like you are comfortable around engines, so I think its a no brainer.
If I build another engine for myself, it will be a 406+. The only question will be stock or aftermarket block. The cost of a retrofit roller cam may or may not be offset by an aftermarket block roller cam ready.
Food for thought, Gary

63 340HP

Yes.

The head gaskets and head casting problems were resolved decades back. The forged aftermarket crankshafts and long rod/piston combinations resolved the bore wear concerns.

There is little to distract from a big inch SBC.

The question today is how high to spin the big cube SBC. With large port heads and forged rods and pistons, the 4000 fpm piston speed limit is not the hard concern of years past. Head port airflow, chamber flame path speed, rotating assemblies, rod to stroke length issues, and internal balance concerns have all been resolved to build a 400+cu SBC that can rev like a L88 427 BBC. Overkill, yes, but doable.

​​​​​​​The OP question and answer however is that a better crate internal balance and forged assembly 383 is a sweet package for the price that will not disappoint.

TCracingCA

I thought someone was wanting to go 400 back to 383, which would be going backyards! I haven't seen any 400 blocks just lying around out at our swap meets in SoCal! Actually good small block period of the Vintage variety are getting scare.

DZAUTO

This is my choice in a heartbeat!!!!
Just recently, I posted about building a roller cam SB400 for my son's 73.
He had not had the 73 for very long and decided it needed more power (not a whole lot of get up and go in a 73 L48) and he wanted to know if I'd help build the L48 into a 383. I asked him why, why not build a SB400. He said "what's a SB400?" So I knew I had to educate the boy.
Long story short. I gave him a short explanation and told him to start looking for a 400. He found a couple for $300-400, incomplete. Then he ran across one (about 100mi from him), carb to oil pan for $250. I told him to grab it. Block and heads were solid and std. Crank was std.
We had it bored .030, had the stock 400 heads opened up real nice (not a full port/polish) with 2.02/1.6 valves, Comp Cam roller kit, .510/.520, 236@ .050 lift, roller tip rockers, flat top pistons and reworked Chevy 350 rods (with new ARP bolts), and added a Chevy windage tray. We also converted the stock 2in ex manifolds/ex system to a full 2 1/2in system. We also had the original Turbo400 rebuilt with a shift kit (had to farm that out, I DO NOT do auto trannys!!!) His Vette is a 73 and as luck would have it, the block is also a 73 casting. Neat. Runs SUPER on 91 octane!
We also dressed it up with some LT1/Z28 parts and a Holley I had in the shop.

68hemi

Tom,
What is the CR on the 1973 400 you built?

ChattanoogaJSB

I'm also curious!

DZAUTO

With the stock 400 heads (~76cc) and flat top pistons, the CR should be about 10:1--------------maybe 9.5, maybe 10.5. But whatever it is, it does just fine with 91 octane.
Back in the day, a 283 with flat top pistons and 64cc heads was about 10:1. With the bigger bore of the 400 and the 76cc heads, that should put it at about 10:1.

karkrafter

I have no personal experience with a 400 build so bear with me, do you think the cam was maybe overkill considering you used the original heads [which I read is the biggest bottle neck on any big inch sbc?]


Would the money have been better spent on a flat tappet smaller cam and a set of Chinese aluminum heads?


Seat of the pants, what do you estimate your HP at? High 300's?

KC John

I think this one looks interesting. What do you guys think?

https://www.skipwhiteperformance.com...hp-base_80557/

I like the specs on the #3 cam choice. I need to know if all the stuff from my ZZ3 will work with this engine. Water pump, headers, fuel pump

I'll have to call and see how much I can customize what I'm buying so I don't have to purchase things I already have.