400 block! - Chevelle Tech
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post #1 of 17 (permalink) Old Dec 13th, 19, 8:05 PM Thread Starter
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Tyler
 
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400 block!

Does anyone know where a guy could find a good 400 block? Preferably a four bolt.
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post #2 of 17 (permalink) Old Dec 13th, 19, 8:27 PM
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Re: 400 block!

in my yard , but the consensus is the 2 bolt blocks are stronger on the 4o0 blocks. jim.
(sorry not selling the 400 right now).

Jim

70 chevelle, SS clone 454 4 speed 3.31 12 bolt posi
71 camaro. (owned since 1978!) 454-th400 3.07 12 bolt
66 chevelle 350 4 speed 3.55 12 bolt and a newly added 142 wieand blower
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post #3 of 17 (permalink) Old Dec 13th, 19, 8:35 PM
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Jeff
 
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Re: 400 block!

Hard to find piece! Thats why Dart and others are making aftermarket ones. Youre better off using a dart shp 400 block anyways. Who wants to dump $1000 buck of quality machining into a marginal oem 400 block? Just my .02 cents.

Jeff

64 El Camino Pro street, 496, T-400, 9" 3.73


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post #4 of 17 (permalink) Old Dec 13th, 19, 8:40 PM Thread Starter
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Tyler
 
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Indeed. I have certainly been thinking about going that route. I’ll probably save my pennies and pull the trigger on that eventually, they are a nice piece for sure.
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post #5 of 17 (permalink) Old Dec 13th, 19, 9:26 PM
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Gary
 
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Re: 400 block!

Dart Sportsman block or there's that other company that makes cast iron blocks for brodix. Don't even consider buying a used 400 block anymore unless you get one out of an old car that's never been apart and you're just building a street motor
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post #6 of 17 (permalink) Old Dec 13th, 19, 11:08 PM
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John
 
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I know a veteran engine builder whose retiring soon and is selling off all his stuff. I just bought a standard bore 2 bolt block that's been cleaned magged and pressure tested and I believe he has another that'll clean up at .030. It's in Spokane, Wa though.
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post #7 of 17 (permalink) Old Dec 13th, 19, 11:21 PM
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Cameron Milne
 
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Re: 400 block!

4-bolt main 400s were 1970-71, possibly into '72 a bit. There were many wive's tales about the 400s, how they would blow head gaskets (ya, on a bad rebuild). The 4-bolt blocks could develop cracks in the webs, whereas the 2-bolt blocks were sufficient for most (and could be machined into 2 extra outer splayed bolts for more strength than the factory 4-bolt).

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post #8 of 17 (permalink) Old Dec 14th, 19, 12:57 AM
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Tom
 
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Re: 400 block!

Quote:
Originally Posted by fr8dog View Post
--------------------------------------------------- Who wants to dump $1000 buck of quality machining into a marginal oem 400 block? Just my .02 cents.

Me!
There are 5 very healthy, hard working 400s in my family. One of them is a 420. With a good, rebuildable core, they make an excellent street-performance-driver.

Tom Parsons
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post #9 of 17 (permalink) Old Dec 14th, 19, 12:59 AM
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Tom
 
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Re: 400 block!

[QUOTE=Jim Mac;11195074]-------------------------------------- but the consensus is the 2 bolt blocks are stronger on the 4o0 blocks. jim. --------------------------------------------------/QUOTE]
I agree, BUUUUUUUUUUUUUT, I've built several 4bolt versions with ZERO issues,

Tom Parsons
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post #10 of 17 (permalink) Old Dec 14th, 19, 1:13 AM
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Tom
 
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Re: 400 block!

Quote:
Originally Posted by Cam View Post
4-bolt main 400s were 1970-71, possibly into '72 a bit. There were many wive's tales about the 400s, how they would blow head gaskets (ya, on a bad rebuild). The 4-bolt blocks could develop cracks in the webs, whereas the 2-bolt blocks were sufficient for most (and could be machined into 2 extra outer splayed bolts for more strength than the factory 4-bolt).

The 70-72 model 400 blocks were 4-bolt ONLY, no 2-bolt.
The 73-80 model 400 blocks were 2-bolt ONLY, no 4-bolt.
Correct.
Correct.
Since 1972, I've built about 25 SB400 engines and have never seen nor had reported any issues with any of them.
The most recent 400 we built was last year for my son's 73 Vette (2-bolt 73 block). It's 10:1, healthy hyd roller and will embarrass some big blocks. The 400 heads that were on the engine were enlarged with 2.02/1.6 valves and mildly massaged. We put it together with 350 rods and the cast crank that came with the engine. A 400 certainly can be built with the shorter 400 rods (5.565in) if there is no intention of spinning it above 5000, but I really prefer the longer 350 rods (5.7in). I have turned the 400 in the 56 Vette to 6600 with ZERO issues. I am not a fan of the 6in rods in a 400. It could have been polished, but we had it turned .010-.010.
In my opinion, the SB400 has gotten a bad rap by too many people that really don't know the ins and outs of a SB400.

Tom Parsons
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post #11 of 17 (permalink) Old Dec 14th, 19, 1:18 AM
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Tom
 
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Re: 400 block!

Quote:
Originally Posted by gnicholson View Post
Dart Sportsman block or there's that other company that makes cast iron blocks for brodix. Don't even consider buying a used 400 block anymore unless you get one out of an old car that's never been apart and you're just building a street motor

This is absolutely true and correct, BUUUUUUUUUUT, when you step up to one of these blocks and a pair of premium aftermarket heads, forget pistons, forged stroker crank, trick cam and valve train, etc, etc, etc, you are suddenly well into the price range of a strong big block.

Tom Parsons
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post #12 of 17 (permalink) Old Dec 14th, 19, 8:12 AM
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Bill
 
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Re: 400 block!

Quote:
Originally Posted by Chebell View Post
Does anyone know where a guy could find a good 400 block? Preferably a four bolt.
I have a good .030 over, 2 bolt short block if you make me an offer I can't refuse. Stock crank and rods with forged pistons. I'm in Columbus Ohio.
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post #13 of 17 (permalink) Old Dec 14th, 19, 9:53 AM Thread Starter
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Tyler
 
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Thank you 69ss396, I will keep you in mind, you are not too far away.
Since most of you are more experienced than me in this department I’ll let you know what I’m thinking then you can tell me how far out to lunch I am. So my car is a 68 136, I got it as a basket case but I am now able to drive and enjoy it........but, it needs more snort. The motor runs good, loves rpm but just doesn’t get it done. It was built similar to the 70 LT1 spec from a four bolt 350 out of a truck, this was done in the 80’s I believe. I would like to pull the engine and stick it in the corner and not cannibalize it. Since the care has 327 badges I would like to keep it a small block (at least for now). Since the 427 was a very potent big block and had a nice ring to it, I would love to snuggle in a 427 small block just because I love that number AND 90% of the population would see 327 on the fender and a small block under the hood and think nothing more than a breathed on small block is keeping the frame rails company. Certainly not going to fool smart fellas but it would be fun either way. So that’s what I would like to accomplish, not really interested in a 383 since they are everywhere...........however a 396 SB could be fun too! 😁
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post #14 of 17 (permalink) Old Dec 16th, 19, 1:26 PM
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Re: 400 block!

can't really build a reliable 427 in a production block. There's just not enough meat in the block. By the time all the grinding in the crankcase is done you'll probably hit water somewhere. Junk block, still owe the machine shop for their work. Loser deal there. If you really want to build a 427 small block plan on an aftermarket like the Dart SHP or similar.

Are you near a competent machine shop? Beware of shops advertising these engines for low prices on the net. these are well known to a bad bet.

Tom Terrific or Terrible Tom, depending on the phase of the moon, passing cosmic rays or other factors not fully understood except by my wife.
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post #15 of 17 (permalink) Old Dec 16th, 19, 6:44 PM Thread Starter
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Tyler
 
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Thank you Tom, yes, is do have a good shop close by. My bosses cousin owns a machine shop so if sh.. hits the fan I can hassle my boss about it. 😁 I am also pretty much set on the Dart block, I certainly don’t want to put thousands of $$ in a questionable block. I’ll have to look again to be sure but I think the Dart block has the factory cam to crank measurement, I think a block with a bigger cam to crank clearance would be beneficial, it shouldn’t require a special cam that way......if I’m right.
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