I came across a 400 with a 4 bolt main but
before I buy I would like your input I know
the 400 will produce good torque and power if set up right but will it last I hear people tell me that there are cooling issues would that be from using heads with out the steam holes basiclly I want it to be a street/strip motor and be able to work well with the 411 gears and an automatic tranny that my car already has and possibly be able to push it to about 6500rpm from time to time so please give me your thoughts

There wont be any issues, 400's are strong if its a street car you can lose some gear with that 400 make it easy on the road maybe 3.42.

If you don't drill the steam holes you will have problems, if you do and don't overheat it it will be ok, however they are much more prone to cracking between the cylinders and blowing headgaskets than the other small blocks. Just look at the space between cylinders on a 350 and 400 block and you can see why.

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There is alot of misconception about a 400sbc. For one: I have never heard of someone having cooling problems with a 400 as long as you have the proper cooling componets. Second the cracking between the cylinders I have heard about but never heard of someone saying they know or having that happend to them. Third headgaskets have not heard of that either.
The 400 sbc has alot of potential value. Even of you dont want it and can get it for cheap, snag it up and resale for a profit. Believe it or not the 4 bolt can sell for more than a 2 bolt

I recently tried to find a 400 4-bolt and gave up because they are simply very, very difficult to find.

I've had one in my Camaro since 1986 and love it. If you do all the normal things to keep it cool that you'd do to a normal 350, they are fine. Some people who have no experience with them immediately complain about the siamesed cylinders, but keep in mind the bow-tie blocks have the same feature.

Sure, if you let them overheat, they fail just like any other SBC. So what?

The only thing you should consider doing is throwing away the factory short rods. Upgrade to at least 5.7" rods (not possible with old technology pistons, but today it's easy) and you will find that you've addressed the only real weakness of the old 400.

dont you meen the 2 bolt can sell for more than the 4 bolt?

<font face="Arial,Verdana" size="2">Originally posted by rsteele:
dont you meen the 2 bolt can sell for more than the 4 bolt?</font>

Actually the 4 bolt does sell for more than the 2 bolt simply because people don't understand that a 4 bolt 400 is a weaker block. They hear 4 bolt and assume that it is stronger, which isn't the case. The 400 4 bolt has weak areas where the outer bolts protrude into the casting of the block which can cause cracks.

I was told to be wary of 2 bolt blocks because of thin cylinders.

Has anyone else found this, or is it an urban legend?

Douglas, of the 400 castings the desirable one is the "509" (3951509) cast between 1974 and 1980. These were 2bolt blocks and had the issue of thin, weak main webs addressed. These are 2 bolt main blocks. The 509 casting from 1970 and 1971 was a 4bolt (only)casting,,, and is reputed to be better than the '817' casting, but the inherrant 400 issues had not been addressed.

You are right, but these can still be had. In fact I just took my '509' 2bolt to the machinist for a sonic check, pressure / mag check, short fill, boring to +.040, decking, having splayed mains fitted, and rough clearanced for a 4" stroke (all for a backup motor). When I dropped the block off the machinist said "auhg,, these 2bolt 509 castings almost ALWAYS have plenty of wall for +.040, and there doesn't appear to be significant core shift in this one, it's the 817 casting that is usually pretty thin" So I left happy as a pig in slop,, I bought this block for $50 about 4 years ago. Then the call comes in,, upon closer inspection we found the block has had one hole sleeved, and a sonic check revealed the top of #3 hole would be pretty thin,, the casting would be a poor candidate to spend nearly a grand on to do all I wanted. He had a '509' 2bolt he had been saving that he'll sell me for $150 'if' we continue with the original plan.

So these blocks are still around and they can be had for a 'reasonable' price. But you really need to make any deal contingent on the block checking out and being servicable. Cracks in the deck (between bolt holes and the bore), cracks in the main webs, and core shift causing thin walls are 'typical' areas to investigate.

I would have never even considered dumping this much $'s into a GM 400 casting if it wern't for the fact that I had the block, I had the splayed mains, I have a set of JE +.040 pistons, I have,,,, well I needed something to toss all this crap on so I could continue with the new motor in the Motown block. With Dart and Motown blocks being under $2k now,, it's a no brainer that dumping $1500 in a GM 400 casting (to make it reliable at 600HP+) just doesn't make sense.

4 bolt is ALWAYS better EXCEPT in the case of the 400SBC when a 2 bolt main is better

I had a good close look at a 509 4 bolt that was already .030 over. 400 cylinder walls are "wavered" as they sit inside the water jacket, but you can find the low spots with calipers thru the deck water holes and the frost plugs bores. I found a .080 lean to the passenger side on the passenger bank and the #8 cylinder was shifted way off and you didn't need sonics ( a good idea ) to check it out.

A .020" 817 I found ( after looking over several ) with not bad core shift was the first one I bought and still have. I have access to magnaflux so I went over it in depth. Overboard in depth. It had the little surface cracks from the steam holes to the headbolt thread. I've seen many of these small steam hole deck cracks and they never seem to go more than about two screw threads deep into the deck. Engine rebuilders I know generally accept them. Take along dye penatrants when shopping and you'll see if they have them or not. I think they are acceptable becuase the rest of the block is perfect but I kept my eyes open for another.

Then I was pointed to a cheap 817 400 short block with a toasted thrust bearing for 100.00. The pan was off, the rear main cap and block saddle were fine. Upon measure and mag, its std", there is even less shift than the first one and it does not have the little steam hole cracks at all. I spent about 12 -14 hours cleaning it up. I had it baked and blasted. I did a partial fill and put water passage restrictors in it. Its being align honed, decked and torque plate fit to the pistons right now. The first one is now the spare.

You can save alot of time by looking over casting bosses and comparing the machine bores. If they are certered then it should be good. It worked 20 years ago and still seems to work today. If the general casting has very little shift in any direction from the outside then the cylinder walls are likely to be pretty good. No garentees but you have to start somewhere when hunting. Be careful I have seen them "for sale" with visible cracks from the head bolt holes into the cylinder!!! Still have not seen a 509 2 bolt for sale of any ilk.

Even some 817 castings will hold up. Just ask Dirt Reynolds. He has been hammering one .060 over for 2 seasons to the tune of mid 11's. It all depends on how good a day the foundry was having http://www.nastyz28.com/ubb/wink.gif

Wow, thanks for all this great info guys.

I sure wish I could get access to one of those awesome blocks they make where I work just 10 miles from here. I don't think the general public can buy them, but I sure wish we could.

The experience and knowledge you guys have is incredible. Thanks for passing it on!

I can't wait to hear your success story Tom once you have that bad boy mounted in the car, better order another set of rears, they seem to melt with 400s. http://www.nastyz28.com/ubb/smile.gif

In spite of popular opinion, don't be afraid of the 4 bolt 400 blocks, my 511 4 bolt has seen many years of abuse, the dyno said 600 HP, factory cast iron crank, passes the magnaflux test every time.

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Custom Auto, your source for quality machine work, cores and new parts at competetive pricing right here in British Columbia 1-888-563-4050
A Canadian, EH? (with a 10 second street car)

And the car is ready for it now! I have a rolling chassis again after 1 1/2 years of chipping away at it. I just need to finish the battery wiring and get my rad. Full report to come soon.

SWEET! http://www.nastyz28.com/ubb/smile.gif

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Custom Auto, your source for quality machine work, cores and new parts at competetive pricing right here in British Columbia 1-888-563-4050
A Canadian, EH? (with a 10 second street car)

Im in the process of building a 406 SBC with a 509 Casting. I had my STD bore blocked baked and cleaned and sonic tested and Mag tested and everything checks out ok. I ordered a internal balanced and spun ballanced forged bottom end for my set up and Im gonna have my machinest stud the main caps and have the mains alined honed just to make sure it is done right. Im still trying to decide which heads to go with but Im leaning toward the 230 Dart Pro 1 Alum heads or do you guys think my 215 Dart Iron Eagles will do the job?

I also have a 400 SBC. Not sure of the casting numbers right now, but I have mine bored over to a 406. Are these motors worth stroking and how far can you stroke them?

Spinmaster IMHO 215-higher is risking a top end only response ( unless you have designs on 7000 rpm? ) and the famed 406 midrange torque evaporates. A lot of guys here are Vortec advocates. For the very good reason that with good flowing 170cc intakes everyone who's tried them loves them.

Better can be done with a 406 street/strip Camaro in the 190 - 200 range. AFRs 190s are popular, likely "the best" but pricey and deliveries can be slow. World, Dart and Iron Eagle all seem to sell into the range for decent pricing. I bought Worlds Sportsman IIs and spent a few hours with a die grinder on them. I think I'll have decent midrange due to the bigger cubes and still pull into the upper rpms at 5600-6000.

Its always a risk once you commit to a plan, but any plan even a bad plan is better than no plan. Worlds are old school but then so am I and mines just a hot rod for our Friday nite street only drags. I hear Iron Eagles are well priced and a newer design with a little better flow than Worlds. I think there all available in iron or aluminum. If your gonna trailer it in and drag it then I guess 215s would be okay.

This is the true beauty of hot rodding ... the chesslike variations on the same themes available to everybody. Its dazzling really but if you watch and see all the different cominations used here but all at their core components are based on the same few principles. Ammoung them are cold air, cool fuel, big cubes, careful pre meditation regarding heads, cams and compression, the best and most exprianced machinist you can find, check every thing they did yourself anyhow, a few other things and oh yeah ... it's all for not if the car can't connect it to the pavement. I do not believe any two regular messagers here run exactly the same "combo". Close but everyone has personnel touches. You gotta love it!

<font face="Arial,Verdana" size="2">Originally posted by spinmaster:
Im still trying to decide which heads to go with but Im leaning toward the 230 Dart Pro 1 Alum heads or do you guys think my 215 Dart Iron Eagles will do the job?</font>

The Dart Iron Eagle is an extremely responsive head in stock form and very responsive to porting. You can make silly levels of power with that head. I would certainly keep that head versus the 230 Pro 1. Keep the compression at 9.5:1.

<font face="Arial,Verdana" size="2">Originally posted by 1982TA:
I also have a 400 SBC. Not sure of the casting numbers right now, but I have mine bored over to a 406. Are these motors worth stroking and how far can you stroke them? </font>

You can safely stroke them to 420 cubes (3.875 stroke) if you have a good block.

I think Ill stay with the 215 Iron Eagles and order a Custom ground Roller cam like this. 108* lobe center & advertised duration is 285 intake and 293 exhaust , The duration at .50 will be 244 intake and 253 exhaust and the gross lift will be .564 intake and .582 exhaust. Im gonna run 11.6-1 compression and a 50/50 mix of 100LL AV gas and 93 prem unleaded gas. This car dosent much street use and I only drive it about 3000-3500 miles a year. I also have a T56 tranny and a set of 4.10s in the rear.

Okay so you are going up there ;-)

I run the weak "511" 400 4-bolt block bored .040. It was sonic checked when built and had enough meat to go .060. I have never had problems with it. A 400 will run as cool as any SBC if it has the proper cooling capacity and is tuned right.

I've often heard rumors of 4-bolt blocks being weaker than 2-bolts. I never really believed it true until a couple months ago. A buddy has a 67 Deuce with the same block as mine running alcohol. It's actually a 3.875 stroker. It's a big tired bracket car running 6.0-6.1's 1/8 mile. One pleasant day his alcohol pump belt flew off. The car hiccuped, stalled and coasted to a stop. It was retrieved back to the pits and a new belt put on. The car started right up but had "0" oil pressure. Upon teardown we found 3 main cap bolts and the oil pump pickup tube in the pan. It cracked all mains deep in the webbing up to the cam journals. Incredible sight to see. We figured it must have been some hell of a detonation to beat the mains out. The funny thing is all the main/rod bearings looked good. The crank was useable, as was all 8 rods and 5 pisons. 3 pistons were scuffed on the skirting pretty bad. This is the reason I won't put NOS on this block.

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409SB, TH350, 4.10 12 bolt
6.86 @ 98.8, 1.47 60'
on pump gas

<font face="Arial,Verdana" size="2">Originally posted by camertom:
Okay so you are going up there ;-)</font>

Hehehe, I like the high RPMs. Im not gonna spin past 7500rpms but I want to be able if needed. I just ordered my Main Support Girdle for the 400 Chevy. The girdle is designed to reduce the main caps from walking on your high horsepower, high torque 400 Chevy. The girdle is made from 1045 medium carbon billet steel and come with 5140 high strength studs and washers. CAT makes it and it's cheap and I figured it won't hurt to have one just incase.

I have the 511 block. I "had" it in my 79' camaro but i took it to 150mph and she developed a mean knock. It really mad me sad, I dynoed it and it put down 260hp and 321tq to the wheels. It was a great engine with tons of tq. What should i Do with it? Build it, sell it???

<font face="Arial,Verdana" size="2">Originally posted by mnhunterman:
I have the 511 block. I "had" it in my 79' camaro but i took it to 150mph and she developed a mean knock. It really mad me sad, I dynoed it and it put down 260hp and 321tq to the wheels. It was a great engine with tons of tq. What should i Do with it? Build it, sell it???</font>

Build it......

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409SB, TH350, 4.10 12 bolt
6.86 @ 98.8, 1.47 60'
on pump gas

<font face="Arial,Verdana" size="2">Originally posted by spinmaster:
Hehehe, I like the high RPMs. Im not gonna spin past 7500rpms but I want to be able if needed. I just ordered my Main Support Girdle for the 400 Chevy. The girdle is designed to reduce the main caps from walking on your high horsepower, high torque 400 Chevy. The girdle is made from 1045 medium carbon billet steel and come with 5140 high strength studs and washers. CAT makes it and it's cheap and I figured it won't hurt to have one just incase.</font>

You'll just be wearing out parts. I suspect it will spin to 7000 but won't be making power. Spin it to 7500 and that will be pretty hard on it. With that cam I suspect it will be pretty much kaput at around 6200 - 6400. I'll lay a 20 on the table and await your engine or chassis dyno results.

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70 SS 454 CI Dynoed 684 HP, 702 TQ All Aluminium Fuel Injected Small Block , plus 200 - 500 HP NX nitrous system.

400 sbc for sale 450 hp. dart steel heads, wilson intake, hyd. roller. 4000.00

400's make power very low. You'd be getting pretty radical to make peak HP at 6000-6500.

If you want all aluminum, great power and the "cool factor", slap an LSx Gen III in it and be way ahead.

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409SB, TH350, 4.10 12 bolt
6.86 @ 98.8, 1.47 60'
on pump gas

<font face="Arial,Verdana" size="2">Originally posted by hals73rs:
If you want all aluminum, great power and the "cool factor", slap an LSx Gen III in it and be way ahead.

</font>

True dat! And you can also stroke 'em to 400 cubes! Can't beat that....a 400 lb. engine with the same amount of cubes.