another "how much can it take" type question..

I've got a question about 400" gm block durability, and what needs to be done to them to take pretty big power reliably.

The reason is the race series rules don't allow aftermarket blocks. I'd be taking all the internals out of the Iron Eagle and going back with a stock block.

BRC crank, carrillo rods, 4.130 ross pistons..

it's got a 101mm turbo breathing down it's neck, so it's got to be pretty tough..

or if it isn't a good idea and won't be reliable, let me know.

thanks!

the odds are not in your favor.
even with 50% fill, and front / rear motorplates you still have limited webbing and hardly any deck to deal with. not to forget pretty thin thrust on the cylinders.

In a perfect world, with no detonation, not torsional stress, and the perfect load....it may live forever.

In the real world...the odds are stacked against you.

My thoughts...call brezinski and have them "retrofit" an iron eagle to look like a GM 400 :D

Dennis

I like the brezinski idea.... or do the same thing to a Bowtie block. Either way if the class allows you to put all these parts on it and not run a good block it's a stupid class in the first place.... the idea is to save money by not allowing aftermarket blocks, it's actually going to cost people more money to run this class since they will break more parts pushing the limit.

Bret

I wouldn't call it a stupid class, IMO. Similar to a class with a tire/wheelie bar restriction. Makes it pretty interesting for the fans, but pretty expensive for the racer.

Ryan

Thanks Dennis, Bret- are you saying it's a waste of time too?

How much power can you make reliably (and don't go saying BigRick this and BigRick that), on a stock block (non-LT1)? We might back the power down to make it live with a stock block..

Here are the rules: http://www.bahraindragracingclub.com/rules.html
The class is #6, Super Street The rules are a little odd, but what do I care :D

One of our dirt track IMCA racers is limited to an original block...we make 510rwhp and every two to three seasons the main-webbings start to break...all the other guys have stepped up classes so we can throw bowtie blocks in there.

I dont see where they say an aftermarket block is against the rules...am I missing it?

line #10 is interpreted as to allow any SBC original casting. The intent of the rule is "no aftermarket blocks and no crossbreeding".

I'd pull a Smokey Yunick and run the Dart since you have it..... unless the rules specifically say "YOU CAN"T Run a DART, WORLD or Bowtie block" I would run one of them. The Bowtie is a GM Casting so it's legal IMHO.

Bret

I have always "heard" that the 400 block weren't that strong. But I have no direct experience with them either.

And about the title, how much can a GMPP crank hold like the one you had in the LT1??

I have a 76 Laguna S3 with a factory 400. It's a 2 bolt main car. The 4 bolt mains actually do not help, and weaken the caps because of less "meat" around and between the bolts. I make 575hp in this car with no bottle, but it does get a 150hp spray on occasion. This engine has been in the car for nearly 2 years and I have had zero trouble with it. I have no cooling issues, either. I don't know how much more power you are looking to get, and maybe I've just gotten lucky...but I wouldn't trade my 400 for anything else. In fact, I would love to know if it's possible to adapt a 400 to work with LT1 heads and intake so I could put it in my 94 Z28.

Zach

The 4 bolt mains actually do not help, and weaken the caps because of less "meat" around and between the bolts. Zach

In your opinion.

My opinion and the opinion of the machine shop where I live that builds 500-2500hp engines on a daily basis. Tell ya what...when I have a failure due to it being a 2 bolt main, I'll apologize. Until then you can just look at tail lights. I do, however, have a 4 bolt 400 that has cracked main caps. The mains of the 400 are bigger than the 350 (obviously) so when you put two holes, instead of one, on a fairly small piece of usuable metal you weaken it.

Zach

Remember, some horsepower numbers have been changed to protect the innocent.

Besides, anyone with a stick Super Duty has no room to talk about strength or durability. Non serviceable ZF=paperweight. The Ford dealership I work at quit ordering them because of so many recalls and failures.

LagunaS3: Just out of curiosity, how much power were you getting out of that 400 block before it cracked? I'm trying to get an idea of how much abuse these blocks can take and still be "safe."

It was the exact same engine as the 2 bolt main. After the 4 bolt cracked I had the crank turned and polished and put everything from the 4 bolt in the 2 bolt. I realize I could've just gotten lucky with the 2 bolt...but I have 3 friends with pretty close to the same engine as I do (2 bolt)....within 20hp anyway. We haven't had any trouble from our engines. You probably know, but it is VERY important to have the steam vents drilled into 400 heads...they cannot sustain RPM's over 3000 without them. One thing I had done to mine was I had every cylinder nickel sleeved. I will PM you with the HP and TQ numbers of my engine.
Zach

Besides, anyone with a stick Super Duty has no room to talk about strength or durability. Non serviceable ZF=paperweight. The Ford dealership I work at quit ordering them because of so many recalls and failures.


I have rebuilt a couple of the ZF boxes....parts are availible, not many ford techs can rebuild a tranny...The only failure point is the weak FORD/Valeo clutch that comes in them. Mine has a dual-disc ceramic clutch which will not fail....our two pull trucks make over 700rwhp and have not broken a tranny, just clutches.

Never seen a 4-bolt break, once they reach a certain HP level we switch to splayed caps... I don't see much broken stuff other than things built by other machine shops, I like to over-engineer and prevent failures. Yes the 2-bolts are strong because of their wide register, I am not disagreeing on that point but main cap failure are usually due to poor main housing bore sizing and/or alignment.

All I can say about my 4 bolt is that the same shop built the 2 year old 2 bolt. At the time I had the 4 bolt built I was warned about main cap failure. It was not splayed...but why splay a 4 bolt (rare) block when a 2 bolt block can handle plenty. I do know that even Mid-America won't touch the internals of Corvette ZF's because very few replacement parts are available. Our Ford dealership also cannot even get the internal parts for Super Duty ZF's or the Focus SVT ZF. Mainly just wanted to pick on you, since you were picking on me.

Zach

how do you "splay" a stock 4 bolt main block?

I think we've decided to try this with a "509" 400 block with the 101mm turbo, what the f*** :D Thanks for the input, if we blow it up, I'll report back..

Brady:

I know this is going to sound dumb, but does a "509" 400 casting have the numbers "509" somewhere on the block? I've heard about these blocks. (They're the high nickel content blocks right?) How do you identify one?

They say 509 on them. That's the block I have. I wasn't aware of the nickel content...but they have thicker water jackets so they can handle overbore better. Mine is not bored, so my engine cools JUST as well as a 350. I was also not aware of a 509 4-bolt. I have an extra 509 bare block at home, so I'll try to get a picture of the "509" on the block and the location of it.

Brady, you probably know, but you will want to get a crank (and flywheel/dampener) for that engine that is internally balanced as the stock style external balance does not contribute to a long life.

Zach

Brady, on a side note, where did you get the chrome Z28 emblems on your car? (In the Mag. article) I have seen RKSport's chrome badges and they are nasty looking with the holes instead of "speed lines."

Zach

how do you "splay" a stock 4 bolt main block?

It can be done but it's not worth the trouble. Laguna is right, the 2-bolt blocks are beefier in the webs, so I'd buy a 2-bolt and splay it.

"Cap breakage" isn't the problem... the 400 usually breaks in the main web or between the cylinders. The first thing you need is a good block. Don't just assume that because you found a "509" that it's good. You'll need someone to sonic check to find a winner. A "good" 400 block can have as much meat in it as a bow-tie.

Back in the 70's, Jack Connely built a number of huge displacement 400's... 440, 454, etc.. Set more than a few drag records with them too. One of Jack's tricks was in finding the "right block" with minimal core shift. He would then plug the coolant holes in the deck surfaces, mill the deck and redrill the the plugs to match those in the head gasket. If the block didn't have coolant holes between cylinders 3-5 & 4-6 (some later blocks) he'd drill and tap for the plug (3/4 NPT) & drill the coolant hole in it. Which is said to help strengthen the block. Adding the center hole helps keep those cylinders from running too hot.

You also have to spend a good deal of time deburing/smoothing the main bulkheads and every nook and cranny of the crankcase area. Jack's blocks even had larger fillets in the bulkheads, courtesy of some serious die grinding I'm sure.

Hey, like you said... build it and see what happens. I'd much rather put a tubo to it than a bunch of nitrous. That's what we did to them many years ago and some held up just fine. With the fine tuning of an EFI setup... there's no telling how much it'll take.

Good luck.

-Mindgame

It can be done but it's not worth the trouble. Laguna is right, the 2-bolt blocks are beefier in the webs, so I'd buy a 2-bolt and splay it.

"Cap breakage" isn't the problem... the 400 usually breaks in the main web or between the cylinders. The first thing you need is a good block. Don't just assume that because you found a "509" that it's good. You'll need someone to sonic check to find a winner. A "good" 400 block can have as much meat in it as a bow-tie.

Back in the 70's, Jack Connely built a number of huge displacement 400's... 440, 454, etc.. Set more than a few drag records with them too. One of Jack's tricks was in finding the "right block" with minimal core shift. He would then plug the coolant holes in the deck surfaces, mill the deck and redrill the the plugs to match those in the head gasket. If the block didn't have coolant holes between cylinders 3-5 & 4-6 (some later blocks) he'd drill and tap for the plug (3/4 NPT) & drill the coolant hole in it. Which is said to help strengthen the block. Adding the center hole helps keep those cylinders from running too hot.

-Mindgame

Splaying a 4-bolt is not good as you said because you are taking even more material away from an already thin main webbing by drilling a third hole there.

This is the exact prep that our stock block 400's go through, find a good 2-bolt core to convert to splayed cap, sonic test for wall thickness, core plugs in the deck add ridgidity, we also run bypass coolant lines tapped into the side of the block.

Even after all this work, the stock blocks at 500+ rwhp and 7500rpm are only good for 2-3 seasons before the main webbing cracks, sometimes on disassembly (after the motor ran fine in the last race) the front main webbing falls out with the crank.

As you said, we had to pass on 3 possible cores last month because of cracks on the deck from the steam holes to a headbolt hole.

Just makes sense to run a sportsman bowtie don't it?

Just makes sense to run a sportsman bowtie don't it?

If rules are dictating that he can't then he CAN'T. Or am I missing something here?

Bret,
You're a young guy... I understand. But keep in mind that some of us not-so-young guys were making big power with the 400 back before all the aftermarket blocks came along.

-Mindgame

This is some awesome info you guys are putting out. One thing that I've heard mention of, but have never actually seen, is this thing called a "block girdle." This supposedly fits down in the main area of the block and is supposed to add strength there. Has anyone ever seen this? Did it help any? I was thinking it might be another possibility to try with solving the strength problem with this block.

By the way, SStrokerAce: Is OldSStroker your Dad by any chance?

Even after all this work, the stock blocks at 500+ rwhp and 7500rpm are only good for 2-3 seasons before the main webbing cracks, sometimes on disassembly (after the motor ran fine in the last race) the front main webbing falls out with the crank.

What? How many times has this happened? 500rwhp and they're breaking?? come on.. we're going to turn it down with the stock block, but it's still gotta be over 1000.. 7500 rpm is not too cool either, I've buzzed my 380 to 9500.. I'm starting to get worried again.. :)

By the way, SStrokerAce: Is OldSStroker your Dad by any chance?

Guilty as charged.

If rules are dictating that he can't then he CAN'T. Or am I missing something here?

Bret,
You're a young guy... I understand. But keep in mind that some of us not-so-young guys were making big power with the 400 back before all the aftermarket blocks came along.

-Mindgame

MG,

Yeah I know but for the guy who has the choice and wants to save a few bucks it's a far cry to say that a 400 is a "cheap" way to go in terms of prep and selection of cores and then the fact that they just aren't that durable.

As I said before I think it's a dumb rule that costs the racer money.

Bret

MG,

Yeah I know but for the guy who has the choice and wants to save a few bucks it's a far cry to say that a 400 is a "cheap" way to go in terms of prep and selection of cores and then the fact that they just aren't that durable.

As I said before I think it's a dumb rule that costs the racer money.

Bret

Oh boy, do I agree with you there Bret. I'll stay off my soap-box on this subject but yeah, just drives the cost of racing through the roof. The hydraulic flat-tappet lifter classes are good examples.

-Mindgame

Brady,
Gm has replaced many a motor in trucks...Warranty replacement was a large call to the removal of the 400 in production vehicles. Living in PA (home of the cheapest racers in the world) I see a good bit of local guys breaking 400's with 5-600 rwhp. Most of the time they are unaware until a freshen (they are ussually curious why the right side of the block is still stuck to the motor mount while the engine is on the engine stand?)

MG is certainly correct that their are some thick 509's availible. The thrust thickness is not your only concern..Lets take a look at this a little closer...

The Situation
1. 3000+ lb vehicle (this is assumed)
2. >1200 HP net (30 years ago, if you were making this kinda of power
it most likely would have been blown on alky...and you were still replacing parts)
3. you are most likely leaving with timing control and supplemental fuel. This will cross cylinders up on the brake.

The Downside
1. Even with .200+ thrust. the cylinders are still floating in the block. the deck and main web are not strong enough to support the diameter of the cylinder with the little engagement they have. On the other hand a siamese block integrates all cylinders, the cylinder not under pressure aid the ones
that are.
2. What is the reason you wish to run a 400 block? their are other solutions, and with the amount of artifical respiration what is the reason you HAVE to have a big bore?
3. If you start to distort a cylinder, the block will not be able to contain the hemorage. This will most likely lead to a massive block failure...say good bye to everything from the oil pan, to that nice BRC crank...to the turbo.
4. In the case of number 3, you have a fair chance that you will track over the carnage unglueing you from the track. Normally sending you on your lid and into the wall, I lost a friend in this situation, and hope to never again. If you do it. buy a diaper their cheap insurance!

their are also ways in order to make the 400 block live. This solution is nothing short of expensive...

you are led to believe that the rules that are in place in any form of racing are to protect the racer... when in reality they are to protect the pocket books of the manufacturers.

I would be glad to offer assistance to this issue, call me anytime...but I stress that whatever decision you make, please sleep on it more than one night.

I'll climb down now...
Dennis

Thanks Dennis!

Thanks Dennis, that's a good read (I read it twice)..

I don't have to have a 400" block, it would just be easier given the parts I already have, and the 18° heads have 2.15 and 1.60 valves. I felt it would be an equitable conversion power-wise. (If it wouldn't grenade.)

One other contingent in this scenario is: Trans-brakes are illegal. This is going to pose quite a challenge to get the car to leave (3400#).. We're going to leave off idle and spray about a 150 shot (dry, FAST controlled) for the first second or so to get the turbo spooled, then drop the nitrous. Tuning won't be an issue, I can make that part happen.

Per "Downside #2", what do you feel is a viable option to the 400 block. We'd like to have something that will last a year anyway, and it pretty much has to run at least 8.50's @ 3400# with a stock block and no trans brake... Geez, these rules are great.. :D

And if you don't think my goals are attainable, by all means let me know.

Oh, and if it isn't painfully obvious, I'm a drag racer, not an engine builder :D

Have you actually called and talked to someone in charge about the use of an aftermarket block?

yes, it's specifically outlawed.. It would be a little tough to sneak the Iron Eagle in.

Are you restricted to a small block? If not use the DRCE II block...made by GM. Or you could put a carb on an LS2 or C5R block!

Zach

Too bad those are LS and BBC blocks and are outlawed from what he said.

I just wouldn't race the class if the rule are this dumb on block selection.

Bret

Here's the deal for those who can't read between the lines.
My 1996 Z28 was purchased by a fine Gentleman in Bahrain. The Bahrain Drag Racing Club (http://bahraindragracingclub.com) has established the aforementioned rules. If you've ever dealt with the Middle Eastern people, you know that they are very "matter of fact" and rules are rules. Nothing is open for interpretation. These rules are quite concrete for the remainder of the year.

Bret, you'd race this series if the money was right, and that's all I have to say. :)

We'll be making the voyage to Bahrain in November, it's going to be pretty cool. The buyer of the car has recently bought Mr. Pat Musi's '69 Camaro, and in talking with Pat, he plans on going to Bahrain in November as well. Mark Dantoni and his crew along with Sonny Leonard and his guys will be going, it should be a fun 24 hours on the plane... Me and MadMan are going to have a wild time in the middle east... Hopefully Brian will return with both hands. :D

Me and MadMan are going to have a wild time in the middle east... Hopefully Brian will return with both hands. :D

Oh dear God...battin' down the hatches...here comes WW III! lol
Or maybe Madman can take a side trip and take care of our problems "over there!" :D

Super Street rules summery

10. All vehicles must run factory equipped engine (Block)


This is the only rule included in this set, (in classes below Pro Street), that dictates anything to do with your choice of engine block. It's actually pretty vague. "Factory Equipped" could be taken a number of ways:

1. The actual original numbers matching engine that was installed in the car
from the factory.

2. The same MODEL of engine that all cars of that type were equipped with
from the factory, but not necessarily the original motor.

3. Any engine that was produced by the same factory that produced the car
it's in.

4. Any engine that was an original factory production engine, regardless of
make.

Now, you're talking about running a 400 block, which pretty much rules out possibilities 1 and 2 as being dealbreakers. So if it's okay to run a 400, seeing as how not a single F Body from 93-02 was ever equipped with one from the factory, then why WOULDN'T it be okay to run an LS1, which was? If I were you, I'd be making some phone calls and asking some questions to gain some clarification about what "factory equipped" actually entails. Because it would seem that if these middle eastern people are as strict about rules and as "matter of fact" as you say they are, then using any block other than a good ol' LT1 is completely out of the question.