400 sbc build
12-02-2004, 06:51 PM
#1
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400 sbc build
I just recently bought and had a 400 block machined and checked for cracks and such. I had the machine shop bore the block .030 over and I am looking for a new rotating assembly of holding 500-550 chp. I was just if anyone has any suggestions on a good crank connectint rods and pistons for such a setup.
12-02-2004, 07:16 PM
#3
Le Mans Master
FYI, you will need to dimple in your crossframe that goes beneath the crank balancer to make room for the giant 400 one. No big deal, just FYI. I think SKI might have pictures, I know someone here does.
12-02-2004, 09:55 PM
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400 build
I have recently gone tthe 400 route and can offer some ideas. First, you don't have to hammer the front crossmember in order to make room for the 400's larger dia. balancer. You CAN purchase an EXT. balanced piece for about $60 that matches the orig. 350's balancer dia. ( 6 3/4" ?) This, of course, if you went with ext. balance. (Probably cheaper than internal (mallory metal + expensive) but you'd have to compute all the pricing and multitude of options to figure the cost and make decision(s). I don't see the need for 6" rods and their added cost. 5.7" stock Chevy w/ aftermarket rod bolts will work well. Unless you plan on a > 150 hp shot of NOS, the cast crank should suffice. Pistons could be cast vs forged. I don't understand the "in between" use of hyperutectics. Go w/ either the cast or forged. You'll need a different dia. flywheel if man. trans (400 flywheel is too big in dia. to fit bell hsg.Centerforce makes a piece(see Summit or Jeg's catalogs) that answers that problem.
Sources might be: Speedomotive, E-Bay( including some interseting Rosebush motor sports "kits"). That's about it, for now. Good luck, Jack
Sources might be: Speedomotive, E-Bay( including some interseting Rosebush motor sports "kits"). That's about it, for now. Good luck, Jack
12-03-2004, 02:04 PM
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Thanks for the replies. I did see that smaller diameter balancer in jegs the other day. I'll have to look through the catalog again for the flywheel. Nitrous is not really out of the equation so id like to use forged parts just incase i decide to put a 100-150 shot on. With that said does eagle have good reputable cranks? I see them and scat cranks on ebay quite a bit.
12-03-2004, 03:07 PM
#6
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Like you, I'm building a 406. I have been shoping all summer and talking to successful builders. I've seen everything from, reusing everything but the old pistons & rings, to some being professionally built for stock car racing. You mention a goal of 500 to 550 hp which is quite doable and a good place to go with this engine. I'll try to highlite a few conclusions I have reached.
Sounds like your over the first hurdel, but magnafluxing and sonic testing for core shifting is paramount to insure you have a sound foundation with good cylinder wall thickness for the boring. Line hone and square the decks. You don't say but I assume you have a 2 bolt main block. They are actually a better choise due to web dementions(less likely to crack). Eagle and Scatt both make excellent cranks, rods etc.. As mentioned above, you can get by on the stock crank but at 550, your pushing it. While one of the forged units would be great, you can step up to cast steel. Considerable stronger than stock and only about $200.00. You can get them for external or internal balanceing. GM Performance has an excelent set of 5.7" rods designed originally for the 383. They are very strong and have a little extra clearence built into the rod bolt area. They are part # 12497870. They are actually cheeper in price than the Eagle H beams by about 85 dollars.
The best heads for me (since I intend to go to TPiS mini-ram) are the GM Performance Parts Fastburn heads. Probably a good head for any application. Summit sales them pre-drilled for the 400 block. You know, the heads require additional holes for proper cooling on the 400 block.
Of course no 400 block, unless recently ordered new from GM or World, was machined for factory roller cam. So If you want to use a roller cam you will have to spring for the hi priced roller lifters.
I'm also installing a hi flow Edelbrock waterpump. Installing a fuel pump block-off plate and don't forget to plug the hole on the front of the block where the small bolt went to hold the fuel pump plunger in the up position for removal of the fuel pump for service.
On Pistons, "Hypereutectic" got a bad rap 10 or so years ago, when first introduced, mostly because mechanics who had been assembleing engines for years, didn't read the instructions which came with them. They found themselves in unformilliar terratory and just fell back on their old, tried and true, methods for installing pistons and rings. The result was a bunch of cratered engines. They are much stronger than standard cast but not what you would pick for a full out race engine. Many of the forged pistons on the market now, are using the so called hypereutectic alloys in their forged pistons but because of the stigma attached to the word, they avoid using it (the word) like the plague. Instead you'll see such clames as, "new alloy allows tighter clearences....".
I put the Keith Black Pistons in my 1980 L-82 and they have worked out great. But for my 406 in my 87, I'll probably use Sealed Power pistons from summit.
Anyway, I wish you well and hope all turns out great.
Sounds like your over the first hurdel, but magnafluxing and sonic testing for core shifting is paramount to insure you have a sound foundation with good cylinder wall thickness for the boring. Line hone and square the decks. You don't say but I assume you have a 2 bolt main block. They are actually a better choise due to web dementions(less likely to crack). Eagle and Scatt both make excellent cranks, rods etc.. As mentioned above, you can get by on the stock crank but at 550, your pushing it. While one of the forged units would be great, you can step up to cast steel. Considerable stronger than stock and only about $200.00. You can get them for external or internal balanceing. GM Performance has an excelent set of 5.7" rods designed originally for the 383. They are very strong and have a little extra clearence built into the rod bolt area. They are part # 12497870. They are actually cheeper in price than the Eagle H beams by about 85 dollars.
The best heads for me (since I intend to go to TPiS mini-ram) are the GM Performance Parts Fastburn heads. Probably a good head for any application. Summit sales them pre-drilled for the 400 block. You know, the heads require additional holes for proper cooling on the 400 block.
Of course no 400 block, unless recently ordered new from GM or World, was machined for factory roller cam. So If you want to use a roller cam you will have to spring for the hi priced roller lifters.
I'm also installing a hi flow Edelbrock waterpump. Installing a fuel pump block-off plate and don't forget to plug the hole on the front of the block where the small bolt went to hold the fuel pump plunger in the up position for removal of the fuel pump for service.
On Pistons, "Hypereutectic" got a bad rap 10 or so years ago, when first introduced, mostly because mechanics who had been assembleing engines for years, didn't read the instructions which came with them. They found themselves in unformilliar terratory and just fell back on their old, tried and true, methods for installing pistons and rings. The result was a bunch of cratered engines. They are much stronger than standard cast but not what you would pick for a full out race engine. Many of the forged pistons on the market now, are using the so called hypereutectic alloys in their forged pistons but because of the stigma attached to the word, they avoid using it (the word) like the plague. Instead you'll see such clames as, "new alloy allows tighter clearences....".
I put the Keith Black Pistons in my 1980 L-82 and they have worked out great. But for my 406 in my 87, I'll probably use Sealed Power pistons from summit.
Anyway, I wish you well and hope all turns out great.
Last edited by Strike3; 12-03-2004 at 03:18 PM.
12-03-2004, 03:26 PM
#7
Le Mans Master
my 2 cents:
Dont use cast or hyper pistons, especially if you plan to spray. you can find an economical forged piston that will not add much to the cost.
Scat has better tolerances than Eagle. In fact the Eagle crank i got didn't even work with a 5.7 rod even tho it was spec'd for a 5.7 rod. Eagle corrected it, but took me a month to get that straightened out. Not to mention having to rebalance the rotating assembly.
Buy a balanced assembly complete. Otherwise you accept the responsibility of doing it and don;t be surpeised if the balance job costs you a small fortune especially if you want to go internal balance.
Use new qualifty studs on the mains
internal or external balance is OK, but make sure you have a plan and evaluate the costs involved. You will be hard pressed to find an externally balanced 153 tooth flexplate. LPE has/had one, but it was very expensive and not SFI approved. You can use a 168 tooth flexplate, but that might involve a new starter and a new inspection cover. And of course consider you plans on the damper (internal/external).
Stream holes in the heads is a topic of debate. I chose not to have them drilled and have had no problems that i know of. If you do drill them you have a chance for another coolent leak that could take out the head gasket. I enlarged the other coolant passages between the cylinders and used a good pump. Your call.
Be prepared to use a small base circle cam. this will largely depend on the rods you choose but you could have clearence problems. I did and had to have the rods ground......see note on balancing rotating assembly.
and lastly, assume nothing fits like it supposed to. this way you will not be disappointed. and check EVERYTHING assuming nothing fits like it's supposed to.
Good luck and have patience.
Dont use cast or hyper pistons, especially if you plan to spray. you can find an economical forged piston that will not add much to the cost.
Scat has better tolerances than Eagle. In fact the Eagle crank i got didn't even work with a 5.7 rod even tho it was spec'd for a 5.7 rod. Eagle corrected it, but took me a month to get that straightened out. Not to mention having to rebalance the rotating assembly.
Buy a balanced assembly complete. Otherwise you accept the responsibility of doing it and don;t be surpeised if the balance job costs you a small fortune especially if you want to go internal balance.
Use new qualifty studs on the mains
internal or external balance is OK, but make sure you have a plan and evaluate the costs involved. You will be hard pressed to find an externally balanced 153 tooth flexplate. LPE has/had one, but it was very expensive and not SFI approved. You can use a 168 tooth flexplate, but that might involve a new starter and a new inspection cover. And of course consider you plans on the damper (internal/external).
Stream holes in the heads is a topic of debate. I chose not to have them drilled and have had no problems that i know of. If you do drill them you have a chance for another coolent leak that could take out the head gasket. I enlarged the other coolant passages between the cylinders and used a good pump. Your call.
Be prepared to use a small base circle cam. this will largely depend on the rods you choose but you could have clearence problems. I did and had to have the rods ground......see note on balancing rotating assembly.
and lastly, assume nothing fits like it supposed to. this way you will not be disappointed. and check EVERYTHING assuming nothing fits like it's supposed to.
Good luck and have patience.
Last edited by ralph; 12-03-2004 at 03:31 PM.
12-03-2004, 08:13 PM
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I have a chance to get one of two 400 2 bolt blocks. One is a bare block that will need to be bored, machined, etc. No pistons, crank, or anything but the block ($150).
The other block has all the machine work mostly done .030 over and comes with Ross Forged pistons. The pistons I was tolds are made for the 5.65 rods I think ($250).
What will be the end performance differences if I used the first one with 6" rods or the second block, which would be the cheaper option?
Please comment on the performance differences affected by rod length.
The other block has all the machine work mostly done .030 over and comes with Ross Forged pistons. The pistons I was tolds are made for the 5.65 rods I think ($250).
What will be the end performance differences if I used the first one with 6" rods or the second block, which would be the cheaper option?
Please comment on the performance differences affected by rod length.
12-03-2004, 09:22 PM
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VSocks
You've got to do some arithmetic and research. It'll be enough to make you think you're a CPA. For ex., if the used block could be machined PROFESSIONALLY by a local maybe that would be ebtter than going with an unknown quality machined-already block. I'd gather as many variables and chart the possibilites. Base decision on $$$ and reliable input. Another ex., how much $ is available vs the total expected cost (always costs more than anticipated--WARNING!
As far as rod length.... the majority of experts will suggext the longer than stock(>5.56" stock 400) rods. That is either the 5.7 or 6.0" The 5.7" are avail. from Chevy( new or USED). Used could be reconditioned vs new (again the cost comparison is needed). Nothing wrong w/ either. Just dollars and sense(Hah!) I don't see the need for more expensive 6.0 rods. Put My $ somewhere else.
On the Ross pistons. I'd be surprised, although I'm not an expert, that they are meant for the 5.56" rods. Ross seems too race oriented but I could be wrong. Check their part No.stamped on piston (?)
Finally, you might look at Speedomotive for some of their part combos or even short blocks. The beauty of that play would be economy(?) and logistics(it's all in a box to your door). Gert out the adding machine. I hope this helps. " Been there done that". Sometimes the local dealers and rebulders can be overboard pricewise but easier to resolve problems with. Planning something like this can become a real can of worms.
As far as rod length.... the majority of experts will suggext the longer than stock(>5.56" stock 400) rods. That is either the 5.7 or 6.0" The 5.7" are avail. from Chevy( new or USED). Used could be reconditioned vs new (again the cost comparison is needed). Nothing wrong w/ either. Just dollars and sense(Hah!) I don't see the need for more expensive 6.0 rods. Put My $ somewhere else.
On the Ross pistons. I'd be surprised, although I'm not an expert, that they are meant for the 5.56" rods. Ross seems too race oriented but I could be wrong. Check their part No.stamped on piston (?)
Finally, you might look at Speedomotive for some of their part combos or even short blocks. The beauty of that play would be economy(?) and logistics(it's all in a box to your door). Gert out the adding machine. I hope this helps. " Been there done that". Sometimes the local dealers and rebulders can be overboard pricewise but easier to resolve problems with. Planning something like this can become a real can of worms.
12-04-2004, 11:03 AM
#10
I would recommend machining a new block and going w/5.7 rods. If you buy the block and pistons you may have to rework your combo. Heads etc, to get the desired results. You will find that it almost always costs more money to make a package work when piece mealing parts together. Take the head you plan to use and pick the correct piston. Or vice versa if you plan to change heads. my opinion, more work goes into the plan than assembling the motor. 
12-04-2004, 12:35 PM
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Originally Posted by vsocks
I have a chance to get one of two 400 2 bolt blocks. One is a bare block that will need to be bored, machined, etc. No pistons, crank, or anything but the block ($150).
The other block has all the machine work mostly done .030 over and comes with Ross Forged pistons. The pistons I was tolds are made for the 5.65 rods I think ($250).
The other block has all the machine work mostly done .030 over and comes with Ross Forged pistons. The pistons I was tolds are made for the 5.65 rods I think ($250).
RACE ON!!!
12-05-2004, 09:18 PM
#14
Le Mans Master
There's lots of places that sell balanced rotating assemblies.
shafiroff.com - is a good one. they carry Eagle & Callies stuff
If you want to go upscale a little try Callies.com. Ask for Wendy. sometimes you can get .010 under cranks for almost the same price as the Eagle and they have balanced rotating assemblies with various rods and piston....very good to work with.
You can go directly to Eagle and maybe Scat too....They have balanced assemblies.
If you are looking for the best price, try these guys: http://www.cnc-motorsports.com. They usually have Eagle blems that have been turned and also carry some Scat stuff.
Good luck
shafiroff.com - is a good one. they carry Eagle & Callies stuff
If you want to go upscale a little try Callies.com. Ask for Wendy. sometimes you can get .010 under cranks for almost the same price as the Eagle and they have balanced rotating assemblies with various rods and piston....very good to work with.
You can go directly to Eagle and maybe Scat too....They have balanced assemblies.
If you are looking for the best price, try these guys: http://www.cnc-motorsports.com. They usually have Eagle blems that have been turned and also carry some Scat stuff.
Good luck
