View Full Version : 421 sbc
jtortorete
02-24-2009, 06:57 AM
Guys
I am building a new 400 block from scratch. I want to build a 421 CID with a 4.155 bore and a 3.875 stroke.
I am looking at a Wheeler kit with their 4130 forged crank, wheeler forged 4140 rods, with forged flat top pistons. The price is not out ragious at $1400.00
Has any one use their stuff? If so what is your opinion of it.
If there is someone you have used please let me know.
dparker
02-24-2009, 07:32 AM
You may want to consider when you bore that 400 block they have a tendancy to split cylinders when you bore them that much. The little M block is just around 1400.00. A very good investment.
robbiequicknova
02-24-2009, 06:02 PM
i have run 40 over 400 blocks for years thats 4.165 bore only one i had crack was after 5 years of abuse and nitrous lots of nitrous450 shot off the line all the way through the quarter
FullTimeRacing
03-02-2009, 12:43 PM
It seems like to me the only people that don't like 400 blocks are the people thet NEVER ran them.
No body says MY 400 broke at this point.
?????????????????????
I have machined alot of 400 blocks over the years and they seem to have the more problems with cranking in the webbing, decks, cylinders ETC then theh 350 blocks we have machined.
Here is a quote from another builder.
-one thing they need to do is sonic test the bores up and down the bores right under each of the 5 head bolt holes per bore----because there is 5 vertical grooves up and down the bores inside the water jackets.
-those grooves are actually the thinnest segments of the bore walls----and they tend crack vertically when high cylinder pressures happen against the bore walls.
-I measured a lot of 400's years ago and found some of these notches to be as thin as .101" to .129"----BUT good notches should average around .186" thick----and good bore walls should average out at about .238" thick.
-I also found that cylinder #6 was always the thinnest and #5 cylinder was the next thinnest.
-400 blocks with casting #330817 have the thinnest walls and are only about .189" average thickness.
-the thickest bore walls I ever found were on the early 1969 to 1972 four bolt main blocks---but those blocks were always weak in the main webs and needed splayed main caps and then fill the empty main bolt holes with some sort of special threaded fastener and use loctite to lock it in there.
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-here's link back to a discussion a few years ago that might be of interest.
http://www.speedtalk.com/forum/viewtopic.php?p=5832&sid=f6dbd90ec3bdc5182ae953f6d3e44f9b
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-sonic testing a stock SBC 400 for a 600HP application is a very tedious job and really should have a map made of each cylinder.
-I seriously doubt that you'd get more than 4--maybe even 8 numbers per bore-----but really that's not enough----it takes way more time to get the entire picture than most people would ever spend.
Here is a good link to look over
http://speedtalk.com/forum/viewtopic.php?t=9126&highlight=400
cepx111
03-03-2009, 10:12 PM
All there saying is to throw caution to the wind, be advised that its a crap shoot using a 400 that big.
JMO> Cp
FullTimeRacing
03-09-2009, 04:12 PM
The one's that broke how much power were they making? To make a genaral statement that there no good is CRAZY .
Not all of us out here can afford to build max horsepower motors or have the chassie to be safe at that speed. :oops: :cry:
can you see core shift with your eye and a flash light?
:shock:
just a few ?
supergass
03-18-2009, 05:15 PM
There have been three that split cylinders around my group of racer friends here. They were all three bracket racers with carbs and no nitrous. One was a fresh motor that was a Lunati crank and pro mod rods motor and he felt the same way as you guys did about the GM blocks because he had good service till then. That block collapsed about the 15th run and took out everything but the heads. It was .040 over with 12:1 compression. I dont know why people are so quick to take it as such a insult that someone makes a possible helpful statement but he is right, hes not making a comment about someones wife or children here! I would run the GM block in a street motor, but based on facts, I will not run them on a race engine anymore. To costly in event of a failure.
It seems like to me the only people that don't like 400 blocks are the people thet NEVER ran them.
No body says MY 400 broke at this point.
?????????????????????
I have machined alot of 400 blocks for other shops and engines builders only to see them fail after a season or two,
Its hard to make chicken soup out of chicken shyt.
can you see core shift with your eye and a flash light?
:shock:
just a few ?
Only with a sonic tester
The SHP block would save you about 600 dollars over a Little-M Sportsman block.
Here are some links on those blocks.
http://speedtalk.com/forum/viewtopic.php?t=12112
http://www.chevelles.com/forums/showthread.php?t=237241
FullTimeRacing
03-19-2009, 04:22 PM
it's not that i get insulted.I do agree that a 421 is out of the ? But a strong 406 is a nice motor for the average guy running low 11's to low 10's .
what's the H/P limit,Is it 600hp 550hp? If you have a nice block. Splayed caps,studedmains ,studed heads,and rok block
That motor that lost the mains (http://forums.racingjunk.com/viewtopic.php?t=8335)In this thread must have been making lots of power,But how much?
it's not that i get insulted.I do agree that a 421 is out of the ? But a strong 406 is a nice motor for the average guy running low 11's to low 10's .
what's the H/P limit,Is it 600hp 550hp? If you have a nice block. Splayed caps,studedmains ,studed heads,and rok block
That motor that lost the mains (http://forums.racingjunk.com/viewtopic.php?t=8335)In this thread must have been making lots of power,But how much?
The dart SHP block is rated at 600 horse and be dependable and a 400 block at 600 I would have to say is not as dependable as the Dart from what I have seen over the years.
zipper06
03-19-2009, 07:59 PM
WoW!!,
Carl 600HP, that's all Dart rates the SHP blk too. Now you got my curiosity up, what do they rate a Little "M" blk at, and what's the major difference in the blks.
Zip.
WoW!!,
Carl 600HP, that's all Dart rates the SHP blk too. Now you got my curiosity up, what do they rate a Little "M" blk at, and what's the major difference in the blks.
Zip.
After looking at the SHP I would say 700 would be the max on that block, The Little-M Sportsman block is rated at 900 horse according to Dart.
The SHP has less nickel content and does not have the heavy bulk heads on the front and rear and they have 3/8 outter splayed bolts and a little less cylinder wall as well.
It will take the GM spider for HYD roller cam set ups
us7race
03-20-2009, 07:37 PM
So what block are the guys making 1200-2000HP sbc's suppose to be using? My friend has a 400 sbc Little M block with a blower. Has been running it for 4-5 years in his dragster no block issue's.
Runs 4.50's 1/8th 1900Lb Dragster.
FullTimeRacing
03-20-2009, 08:57 PM
I read on the dartshp.com site the shp is good to 600 hp.
so i joined and asked what the maximum hp is .
waiting for a answer
FullTimeRacing
03-20-2009, 09:06 PM
So what block are the guys making 1200-2000HP sbc's suppose to be using? My friend has a 400 sbc Little M block with a blower. Has been running it for 4-5 years in his dragster no block issue's.
Runs 4.50's 1/8th 1900Lb Dragster.
dart makes 4 iron blocks, shp,little m sportsman,little m,and iron eagle.
i would say iron eagle or the alumium block.
I read on the dartshp.com site the shp is good to 600 hp.
so i joined and asked what the maximum hp is .
waiting for a answer
After looking at the SHP I would say 700 would be the max on that block, The Little-M Sportsman block is rated at 900 horse according to Dart.
The SHP has less nickel content and does not have the heavy bulk heads on the front and rear and they have 3/8 outter splayed bolts and a little less cylinder wall as well.
It will take the GM spider for HYD roller cam set ups
FullTimeRacing
03-22-2009, 06:34 PM
I also read on the dart forum that a few of the blocks have had main journal alinement issues,so they all have to be checked when you buy one
I also read on the dart forum that a few of the blocks have had main journal alinement issues,so they all have to be checked when you buy one
I will post a new thread on this issue, But it was only on a few blocks and ow Dart line hones all there SHP blocks.
Here is a link on that
http://speedtalk.com/forum/viewtopic.php?p=161974&highlight=#161974
bftstam
03-25-2009, 05:21 AM
I had a 406 that I bracket raced for years. 5.7 rods, 12-1, roller,ported bow tie heads. Wonderful combination for a 3000# bracket car. Ran 10.40s and lasted for years and years - rings bearings and valve springs was all it ever needed. Then I got into DOT index racing and using nitrous......... 3 blocks in 3 seasons. Cracked cylinder wall was the main culprit and one cracked between the steam holes and the headbolt holes. none of them ever got hot either. Now I look back and think about all the money I spent machining those stock blocks which could have paid for a good block.
I now have a Dart little M. So yes, a stock block is fine to a certain point.
TheEngineer
03-25-2009, 09:09 AM
I'm going with the Dart SHP block for my SBC 427 build (4.125 bore x 4.00" stroke). It's going in my 2320 pound tube-chassis Cavalier and the car should fly with that new engine.
WD
curtisreed
03-27-2009, 06:13 AM
I'm going with the Dart SHP block for my SBC 427 build (4.125 bore x 4.00" stroke). It's going in my 2320 pound tube-chassis Cavalier and the car should fly with that new engine.
WD
Engineer,
Nice car, glad to see some more Okies on here.
Curtis
stickshift70
04-02-2009, 05:46 PM
well im a okie too i build alot of motors fopr the dirt and for the street the only thing that ive found thats bad about a stock 400 block is when you start putting alot of compression in it it will splitt the clylinder walls i have a 418 ci 18 degree headed motor for sell on rj compression around 16.1 its built out of a stock block with spayed billet caps dyno time only .. but my other builds are still running and still running strong , i have not split a block in about 3 years the last one split # 5 cly. but it was a blower motor it ran in the low 8 sec. range street car so good luck building your poject oh as for wheeler products they are just as good as any but it still depends on what you buy and what you are trying to build as in how much power you want to make
oldandtired
04-14-2009, 06:53 AM
Agree with the Jones statement posted by Hink. I am a straight line runner, but my roundy-round guys always start with a 2 bolt 400 block and convert to splayed outer bolts due to the weak webbing.