400 Build - Need advice!
Thread Starter
Melting Slicks
Joined: Apr 2002
Posts: 2,546
Likes: 0
From: Orlando FL
400 Build - Need advice!
Hey Guy's -
I recently picked up a 4 bolt 400 block that is .30 over. Casting #511. I would like to build a motor that puts down around 450 to the wheels. The heads I am currently looking at are Dart Pro 1 Aluminums that have been worked over. They flow 290 intake, and 260 exhaust. They have been gasket matched to either 1205 or 1206 gaskets. I am told that they have dual 1.437 springs, part ferrea and part dart valves, and can handle up to .650 lift. 5angle valve job, 2.02/1.60 valves.
My questions are this - will these heads flow enough to get me the numbers I want on pump 93 gas? I have heard guys making in the neighborhood of 550 chp with these heads worked, but I want confirmation. Also - What suggestions for pistons and rods might you have? I have a set of new sealed power 400ap pistons I thought might work based on PeteK's experience with Hypers. I am a bit reluctant, but I have heard seen and heard hyper pistons make great power.
Thanks!
I recently picked up a 4 bolt 400 block that is .30 over. Casting #511. I would like to build a motor that puts down around 450 to the wheels. The heads I am currently looking at are Dart Pro 1 Aluminums that have been worked over. They flow 290 intake, and 260 exhaust. They have been gasket matched to either 1205 or 1206 gaskets. I am told that they have dual 1.437 springs, part ferrea and part dart valves, and can handle up to .650 lift. 5angle valve job, 2.02/1.60 valves.
My questions are this - will these heads flow enough to get me the numbers I want on pump 93 gas? I have heard guys making in the neighborhood of 550 chp with these heads worked, but I want confirmation. Also - What suggestions for pistons and rods might you have? I have a set of new sealed power 400ap pistons I thought might work based on PeteK's experience with Hypers. I am a bit reluctant, but I have heard seen and heard hyper pistons make great power.
Thanks!
Last edited by quiksilver458; Jan 6, 2010 at 07:23 PM.
Racer
Joined: Sep 2007
Posts: 493
Likes: 0
From: Eden Utah
Hey Guy's -
I recently picked up a 4 bolt 400 block that is .30 over. Casting #511. I would like to build a motor that puts down around 450 to the wheels. The heads I am currently looking at are Dart Pro 1 Aluminums that have been worked over. They flow 290 intake, and 260 exhaust. They have been gasket matched to either 1205 or 1206 gaskets. I am told that they have dual 1.437 springs, part ferrea and part dart valves, and can handle up to .650 lift. 5angle valve job, 2.02/1.60 valves.
My questions are this - will these heads flow enough to get me the numbers I want on pump 93 gas? I have heard guys making in the neighborhood of 550 chp with these heads worked, but I want confirmation. Also - What suggestions for pistons and rods might you have? I have a set of new sealed power 400ap pistons I thought might work based on PeteK's experience with Hypers. I am a bit reluctant, but I have heard seen and heard hyper pistons make great power.
Thanks!
I recently picked up a 4 bolt 400 block that is .30 over. Casting #511. I would like to build a motor that puts down around 450 to the wheels. The heads I am currently looking at are Dart Pro 1 Aluminums that have been worked over. They flow 290 intake, and 260 exhaust. They have been gasket matched to either 1205 or 1206 gaskets. I am told that they have dual 1.437 springs, part ferrea and part dart valves, and can handle up to .650 lift. 5angle valve job, 2.02/1.60 valves.
My questions are this - will these heads flow enough to get me the numbers I want on pump 93 gas? I have heard guys making in the neighborhood of 550 chp with these heads worked, but I want confirmation. Also - What suggestions for pistons and rods might you have? I have a set of new sealed power 400ap pistons I thought might work based on PeteK's experience with Hypers. I am a bit reluctant, but I have heard seen and heard hyper pistons make great power.
Thanks!
I have a 406 sbc, 244/244 600 lift. LSA 110, 4340 crank and rods, hyper pistons, mini ram, built 700-R, 3000 stall, 42# injectors, gen 7 dfi, full length headers, no cat, dual exhaust 10.5 to 1 compresion ratio, fully balanced motor. Be prepaired to spend some time tuning, and purchasing tires. Now other than that it is a blast to blow off just about everybody.....
Safety Car
Joined: Sep 2001
Posts: 4,157
Likes: 554
From: Glenbeulah Wi
Your heads are good enough to make 450 RWHP. Take a look at my sig, I have a combination that meets your goals with a 406.
I am not a big fan of Hyper pistons in a higher compression higher RPM engine. A hyper piston works well for low to mid RPM engine builds but they are not really intended for high RPM (<6000 RPM) operation and they do not tolerate detonation well. A hyper piston is a cast piston with high levels of silicon and which makes it hard (stronger then cast only) but brittle, so if you experience detonation they have a tendency to crack. If you are looking for 550 CHP I would use a forged piston since you will be exceeding 6000 RPM on power pulls and your compression will be high enough that you could experiece detonation if something doesn't work as planned. The forged piston offers more protection against unexpected issues.
I like Mahle and SRP pistons since they both are light weight and offer a flat top 406 piston for the 6" rod. The Mahle piston does not put the pin into the oil ring which some people like better but I have used both and they both worked well with no unusual oil control issues. I am sure there are many other acceptable pistons that can do the job, it will just take some research to find one that fits with your current parts selection.
I am not a big fan of Hyper pistons in a higher compression higher RPM engine. A hyper piston works well for low to mid RPM engine builds but they are not really intended for high RPM (<6000 RPM) operation and they do not tolerate detonation well. A hyper piston is a cast piston with high levels of silicon and which makes it hard (stronger then cast only) but brittle, so if you experience detonation they have a tendency to crack. If you are looking for 550 CHP I would use a forged piston since you will be exceeding 6000 RPM on power pulls and your compression will be high enough that you could experiece detonation if something doesn't work as planned. The forged piston offers more protection against unexpected issues.
I like Mahle and SRP pistons since they both are light weight and offer a flat top 406 piston for the 6" rod. The Mahle piston does not put the pin into the oil ring which some people like better but I have used both and they both worked well with no unusual oil control issues. I am sure there are many other acceptable pistons that can do the job, it will just take some research to find one that fits with your current parts selection.
Last edited by bjankuski; Jan 7, 2010 at 08:23 AM.
Team Owner
Joined: Oct 2004
Posts: 81,241
Likes: 3,063
From: altered state
St. Jude Donor '05
Ditto on what Bjanski said. Personally Id ditch that block (get a Dart)at 550hp range its an iff y proprosition. May last yrs, may last a week.
Be nice to see a solid roller in that mill too.
Be nice to see a solid roller in that mill too.
Drifting
Joined: Dec 2005
Posts: 1,360
Likes: 3
From: NORTHEAST
Your heads are good enough to make 450 RWHP. Take a look at my sig, I have a combination that meets your goals with a 406.
I am not a big fan of Hyper pistons in a higher compression higher RPM engine. A hyper piston works well for low to mid RPM engine builds but they are not really intended for high RPM (<6000 RPM) operation and they do not tolerate detonation well. A hyper piston is a cast piston with high levels of silicon and which makes it hard (stronger then cast only) but brittle, so if you experience detonation they have a tendency to crack. If you are looking for 550 CHP I would use a forged piston since you will be exceeding 6000 RPM on power pulls and your compression will be high enough that you could experiece detonation if something doesn't work as planned. The forged piston offers more protection against unexpected issues.
I like Mahle and SRP pistons since they both are light weight and offer a flat top 406 piston for the 6" rod. The Mahle piston does not put the pin into the oil ring which some people like better but I have used both and they both worked well with no unusual oil control issues. I am sure there are many other acceptable pistons that can do the job, it will just take some research to find one that fits with your current parts selection.
I am not a big fan of Hyper pistons in a higher compression higher RPM engine. A hyper piston works well for low to mid RPM engine builds but they are not really intended for high RPM (<6000 RPM) operation and they do not tolerate detonation well. A hyper piston is a cast piston with high levels of silicon and which makes it hard (stronger then cast only) but brittle, so if you experience detonation they have a tendency to crack. If you are looking for 550 CHP I would use a forged piston since you will be exceeding 6000 RPM on power pulls and your compression will be high enough that you could experiece detonation if something doesn't work as planned. The forged piston offers more protection against unexpected issues.
I like Mahle and SRP pistons since they both are light weight and offer a flat top 406 piston for the 6" rod. The Mahle piston does not put the pin into the oil ring which some people like better but I have used both and they both worked well with no unusual oil control issues. I am sure there are many other acceptable pistons that can do the job, it will just take some research to find one that fits with your current parts selection.
One other thing to check on 400 block is to have the cylinders sonic tested for proper cylinder wall thickness
At the level of HP your looking at that would these 2 areas are a must on the 400 block
If it fails the Dart SHP block would be a good choice.
Good luck with your build.
Le Mans Master
Joined: Feb 2000
Posts: 9,715
Likes: 27
From: Kempner Texas
The exhaust flow seems high. Are you sure about the exhaust flow number you posted?
If it is accurate, that puts the intake/exhaust flow ratio near 90% which will effect cam selection.
Jake
If it is accurate, that puts the intake/exhaust flow ratio near 90% which will effect cam selection.
Jake
Thread Starter
Melting Slicks
Joined: Apr 2002
Posts: 2,546
Likes: 0
From: Orlando FL
That is what the flow sheets show from the machine shop. The heads are on a 383 stroker motor in a 3rd gen camaro. Car runs high 10's with full interior. So - I am assuming the combo he is running works very well for the power he is making.
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Burning Brakes
Joined: Feb 2002
Posts: 804
Likes: 5
From: Fresno CA
I would say those heads should put you in the ballpark. What manifold are you running? I have a 511 block .040 over and as stated above you should definitely have it mag'd and sonic'd prior to investing in any machine work. I also agree about upper cylinder distortion on those blocks and on mine we used Moroso deck plugs both to strengthen the deck surface and improve cooling. I wouldn't personally run a hyper piston either; spend the extra money and use a quality forged piston, I'm using Ross 10.3:1's w/6" rods and a 4340 Scat crank. Some people say only use a 2-bolt block because the 4-bolt blocks have weaker main webs but if you use ARP studs and aren't turning really high rpm's, blown, or N2O'd you will be fine; especially if you are using a hydraulic rollers with a max of 6200 rpms. Plan your build carefully and you should have a nice piece. I have basically out of the box Dart Pro1 200's gasket matched to a 1205 Fel-Pro gasket and a ported SuperRam since my car is an automatic. Do your homework matching your induction system, heads and camshaft; that's going to determine the outcome. I'm using 42# injectors also and a Gen VII DFI w/WBO2. I haven't gotten it on the dyno yet but judging by the way it runs I'll be surprised if it doesn't go over 400RWHP.
Safety Car
Joined: Sep 2001
Posts: 4,157
Likes: 554
From: Glenbeulah Wi
Drifting
Joined: Dec 2005
Posts: 1,360
Likes: 3
From: NORTHEAST
We have dealt with a lot of blocks over the years and with the phone calls and emails I have gotten I have had more calls about broken 400 blocks then the 350 block.
Think about it bigger bores, thin decks, big main lines its going to be a much weaker block then the 350 block. And having the main bolts spread apart more then the 350 really makes for a weak link. Look at the 400 blocks with just cracked decks
Here are two of my favorites as these engine were suppose to be built correctly
Safety Car
Joined: Sep 2001
Posts: 4,157
Likes: 554
From: Glenbeulah Wi
We have dealt with a lot of blocks over the years and with the phone calls and emails I have gotten I have had more calls about broken 400 blocks then the 350 block.
Think about it bigger bores, thin decks, big main lines its going to be a much weaker block then the 350 block. And having the main bolts spread apart more then the 350 really makes for a weak link. Look at the 400 blocks with just cracked decks
Here are two of my favorites as these engine were suppose to be built correctly
Think about it bigger bores, thin decks, big main lines its going to be a much weaker block then the 350 block. And having the main bolts spread apart more then the 350 really makes for a weak link. Look at the 400 blocks with just cracked decks
Here are two of my favorites as these engine were suppose to be built correctly
Race Director
Joined: Jun 2009
Posts: 10,428
Likes: 9
From: Southside of Western Norte Americano State of Confusion, ColoFornia
St. Jude '13
I normally dont interject in these types of "technical discussions" as the opinions are usually held with the same level of fervor as Religious viewpoints.
But... For street use.. and define that as occasionally getting on it.. a 400 2 bolt block is as good as any other.. The difference is in what YOU do with it.. not in how much high dollar shiny parts you throw at it.
a 400 is and was intended as a torque motor but 6k-to 7k RPM once in a while isnt going to hurt it. 10 passes a week on a drag strip or road course is going to destroy it in short order..thus the definition of Street motor. A high dollar 4 bolt block is certainly better for that type of stuff, but in my experience most guys buy and build far more engine than they need, "Just in Case" the bigger is better syndrome.
In my humble opinion, the best "extra money" you can spend is to make sure the block is sound to start with.. and balance the rotating assembly.
Im now climbing into the flameproof hardened bunker to wait out the storm..
But... For street use.. and define that as occasionally getting on it.. a 400 2 bolt block is as good as any other.. The difference is in what YOU do with it.. not in how much high dollar shiny parts you throw at it.
a 400 is and was intended as a torque motor but 6k-to 7k RPM once in a while isnt going to hurt it. 10 passes a week on a drag strip or road course is going to destroy it in short order..thus the definition of Street motor. A high dollar 4 bolt block is certainly better for that type of stuff, but in my experience most guys buy and build far more engine than they need, "Just in Case" the bigger is better syndrome.
In my humble opinion, the best "extra money" you can spend is to make sure the block is sound to start with.. and balance the rotating assembly.
Im now climbing into the flameproof hardened bunker to wait out the storm..
Race Director
Joined: Jun 2009
Posts: 10,428
Likes: 9
From: Southside of Western Norte Americano State of Confusion, ColoFornia
St. Jude '13
What I am saying is for a street application 7000 RPM and 600 HP is no problem with a 400 SBC with the correct applictaion of parts. If you choose to build a race application then choose an aftermarket block and the correct rotating internals and you can rev it to the limit of valve train control before you will break the block. My basic statement is get rid of the short 400 rods in a production 400 and add in 6" rods and you can rev as high as any production blocked 383 combination.
Drifting
Joined: Dec 2005
Posts: 1,360
Likes: 3
From: NORTHEAST
What I am saying is for a street application 7000 RPM and 600 HP is no problem with a 400 SBC with the correct applictaion of parts. If you choose to build a race application then choose an aftermarket block and the correct rotating internals and you can rev it to the limit of valve train control before you will break the block. My basic statement is get rid of the short 400 rods in a production 400 and add in 6" rods and you can rev as high as any production blocked 383 combination.
. I have seen both blocks and the Dart is light years ahead of the GM 400 blocks.
Instructor
Joined: Feb 2001
Posts: 211
Likes: 0
From: Chicago ILL
I'm not going to debate the block issue. I used a 400 2 bolt because I bought the motor from a guy who had it in his mid 70's Chevy. It was a stocker.
Knowing that the 400 had oiling issues, I wanted to go with a longer rod. I chose to use the stock crank, Eagle 6" rods and SRP flat top pistons. The rods and pistons were much lighter than stock which allowed a significant amount of weight to be removed from the crank. I also had the block zero decked. In my opinion quench is crucial. I targeted an exact .040". My compression is 11.0-1 and I have no problem with 93 octone fuel.
For cam, I went with a Comp custom grind solid roller with a 4/7 firing order swap. Haven't put the car on the chassis dyno so cannot give hard numbers. I will say that for all out peformance, you can't beat a solid roller.
Knowing that the 400 had oiling issues, I wanted to go with a longer rod. I chose to use the stock crank, Eagle 6" rods and SRP flat top pistons. The rods and pistons were much lighter than stock which allowed a significant amount of weight to be removed from the crank. I also had the block zero decked. In my opinion quench is crucial. I targeted an exact .040". My compression is 11.0-1 and I have no problem with 93 octone fuel.
For cam, I went with a Comp custom grind solid roller with a 4/7 firing order swap. Haven't put the car on the chassis dyno so cannot give hard numbers. I will say that for all out peformance, you can't beat a solid roller.
Safety Car
Joined: Sep 2001
Posts: 4,157
Likes: 554
From: Glenbeulah Wi
Blockman I am not trying to bust your chops or anything I am just answering the original question. You know as well as I do that GM rates the stock production block 350 or 400 at 450 HP. We also know that many people have run more then 450 HP through them. How long will they last is anyones guess. I have personally built 700 HP 410 sprint car engines out of a 400 block in the 90's (before we had good aftermarket blocks) that have lasted an entire racing season (I have also seen some explode after a few nights. What I have stated is that if people are willing to run 600 HP through a production block 383 then you will be able to run that same power level through a production block 400. I did not state that a Dart SHP block that is rated for 600 HP is no better then a production block.
Drifting
Joined: Dec 2005
Posts: 1,360
Likes: 3
From: NORTHEAST
Blockman I am not trying to bust your chops or anything I am just answering the original question. You know as well as I do that GM rates the stock production block 350 or 400 at 450 HP. We also know that many people have run more then 450 HP through them. How long will they last is anyones guess. I have personally built 700 HP 410 sprint car engines out of a 400 block in the 90's (before we had good aftermarket blocks) that have lasted an entire racing season (I have also seen some explode after a few nights. What I have stated is that if people are willing to run 600 HP through a production block 383 then you will be able to run that same power level through a production block 400. I did not state that a Dart SHP block that is rated for 600 HP is no better then a production block.
I understand what your saying but a 350 block has a stronger decks, stronger webbing and stronger 4 bolt caps than 400 blocks.
Like I stated I have gotton more calls on broken 400 blocks then 350 blocks if that tells you anything.
Instructor
Joined: Dec 2009
Posts: 111
Likes: 1
its unbelievable how awesome you are.. and how in all your post you have a condescending unwanted response to all the people who post their knowledge even if you agree with them.