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400 Cracked Block Blues (x3)....

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MrDanB

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Discussion starter · #1 ·
Some of you might remember that I had purchased a 400 block and was all excited to build it up into a monster (well, a little monster anyway) I got word back about a month ago: "Sorry Dan, too much rust to machine out", then I get a 2nd 400 block from a very good friend..."Sorry Dan, crack in the lifter valley". So the Engine builder tells me that he feels bad for me and that he took one in on trade, but not sure if it's good or not. Just heard back today: "Sorry Dan, crack in the lifter valley" :sad: I know I'm not the first guy to have 3 in a row turn out "bad"...it still sucks though! I'm probably going to just save up a little and go buy a Motown 434 short block from Ohio Crank or somewhere. Aside from ranting... I was curious if this is common to have several turn up cracked/bad? Any horror stories? I know it's not Bench, but it IS Performance related (lack of performance :D )

Dano :clonk:
 
#2 ·
Dan sorry about your woes. If you didn't have bad luck... I have heard of a few cases here and there where the 400 blocks tend to have cracks. That's why I settled for the next best thing (383). Seems like a lot less issues with the 350 blocks and cracks (at least from my limited experience). Sounds like you can't go wrong with the 434. I think that's what I might go with for my next engine depending on how impressed I am with my 383's performance. Keep us posted.
 
Discussion starter · #3 ·
yeagh...I just finished rebuilding my 327 last year and ran it for a while, but the 'speed bug" got ahold of me...you guys know what I mean. I'll keep you posted...

Dano :thumbsup:
 
#4 ·
I'm always tempted to run out and jump on the latest 400 block that will usually pop up in the local "IWANNA" trade paper about every other week. I've never made the move for fear of just what has happened to you. For all I know some of these same blocks may just get passed around to the next guy from week to week. At the grocery store the other day I saw a huge 4 door Impala with 400 emblems on it and thought now that's the 400 for me but doubt I’d pry that one away from the owner. The after market blocks are looking better and better and with all other things perhaps increased sales volume may lower the price in the long run.
 
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Discussion starter · #5 ·
Yeagh Robert, You're right. The 400 makes for nice cubes, but a stout 383 will do just fine, and they're still readily available. I looked at Craigs list and found 2, but 1 sold the very hour the ad came out and the other one was too far for me to go look at (6+hours) So, I might just enjoy the 327 for now, get that old posi w/3.36 gears all fixed up and stick that in the 69 car and do the LS1 brake upgrade and call it good for now. I'm runnin' 3.23 open right now and just never made time for the posi axle rebuild. I can give some thought to what I want to run over the winter, then persue it later. Nice garnet red you got there by the way :D

Dano :beers:
 
#6 ·
I think when i do a big cube small block down the road im going to definately go with an aftermarket block. Specifically the Dart IE block. Theres just too much to worry about with the factory 400 blocks. Over heating, cracking, weak webbing, etc. And by the time you find a block, get it cleaned, magnafluxed, possibly sonic checked, bored, honed, square decked, buy and install splayed billet caps, align bore, and clearance it for a stroker crank, i think the few hundred extra dollars for the far superior foundation would be worth it. Plus later on youll still have a few bores to dink with if you only go 4.125 off the bat. And after looking at the block in person ive concluded you couldnt break one with a 25lb. sledge hammer.
 
#8 ·
Dan,
Sorry to hear about your luck. I can't say I am surprised. It's not only the 400 blocks, the 350 blocks have the same issues. there are just a lot more 350's to pick through. I think I told you I went through 3 or 4 blocks (350's) before I found one that was buildable. Two or three had cracks in the lifter valley (typicall place for SBC to have cracks) and one had core shift that was too bad.

I highly doubt I will ever build another high HP factiry blocked engine. I will go aftermarket as well.

Matt,
You are a lucky man. Have you had those blocks mag'd? If not they might not be so good. HTe cracks are usually too small to spot with the naked eye. Once they are mag'd to find them, then you can see them with the naked eye. Hopefully for you they are all good. Hang on tight to them cause they are drying up for sure.
 
#9 ·
Yeah, they've all been tested. I wont machine a 400 without testing them first (well, any block for that matter). I agree that it's not just 400's, it just about all of them that can be troublesome.

I tend to collect these blocks because, like you said, are getting hard to find. I paid $80 for one (with rotating assembly), and the other was free (with crank only). After these are used up, I'm going either aftermarket, or LS motors.

By the way, World will now be casting LS blocks with standard SBC mounts. Should make swaps a breeze.
 
#10 ·
Good 400 cores are getting hard to find in certain parts of the country. Sounds like you have exceptionally bad luck though . . .

If I hadn't found my 509 casting in good condition, I probably would have build another 383 . . . or if I hit the lotto, built an aftermarket tall deck block.
 
#11 ·
We have repaired a lot cracks in the lifter galley on racing blocks that have froze over the winter we use the LOCK-N-STITCH method over the years we have repaired alot of 010 blocks with a 100% success.

The Dart Little-M block with nodular caps is a good choice all machined and shipped they run about 2295.00 which seem to be a hot seller lately as that maybe an option for you. We are W-D with all the top companies as far as hard engine parts and offer balanced assemblies something to think about.

Hope things work out for you what ever way you go.
 
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Discussion starter · #12 ·
Thanks Carl! It's always a crap shoot if they have cracks or not. After seeing the core shift on the first block compared to #2 and 3, I'm pretty skeptical about the quality in these 35+ year old blocks. Probably I'll just slow down and get some other projects done for now, then see if anything catches my eye. And YES I will check out your website Carl ;)

Dano :beers:
 
#13 ·
MrDanB said:
Thanks Carl! It's always a crap shoot if they have cracks or not. After seeing the core shift on the first block compared to #2 and 3, I'm pretty skeptical about the quality in these 35+ year old blocks. Probably I'll just slow down and get some other projects done for now, then see if anything catches my eye. And YES I will check out your website Carl ;)

Dano :beers:
Click to expand...
From what we have seen as far as core shift we have seen blocks severe core shift but the cylinders seem to be centered and and if we could go by only core shift in a block it would have saved me 1200.00 dollars.

We have found many blocks that 7 cylinders sonic real good and one will be .400 on one side and .125 on the other making it a non desireably peice.

If somebody in your area can sonic test a block there might be a keeper in the bunch hard telling and we charge 40 dollars for that operation.
 
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Discussion starter · #14 ·
I think I paid 100 bucks for tank and magnaflux, then 40 for ultrasonic check, but then, I never got far enough along to get one to the ultrasonic portion :D Somthing will turn up. I think I'll wait until I see an ad like this: "wrecked my car, parting out, fresh 400 sbc, hear it run before I pull it". Not too often this happens, but if you're "Johnny on the spot.." lol Anyway, We have the buy and sell, little nickel, etc. + I'm always checking for parts at the wrecking yard...

Dano :beers:
 
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MrDanB
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