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Old 03-17-2010, 02:55 PM
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421 sbc

howdy i have asked questions about this before and was looking up all the parts i would need to do the build that was recommended on this form. Here is what was the one that they recommended to me for a strip set up.

"that all really depends on what you want to do with the motor, if you want an all out strip car i would go with a set of CNC'd alm brodix, AFR, or DART heads that are around 220+cc runners w/ 2.08-2.10 int valves, a a nasty solid roller cam in the area of, 260ish advanced duration and .600"+ lift and probably close to 12.5-13.5 Compression, but this wouldn't be very street friendly as it would likely make around 650hp"

i have a 400 small block that i'm doing a 30 over bore on with a 3.875 crank. i'm getting the rotating assembly from competition products. Now i'm trying to find a cam shaft that matches to these specs any recmmondations

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Old 03-17-2010, 03:28 PM
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is it a 2 bolt or a 4 bolt block?
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Old 03-17-2010, 04:55 PM
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well i actually have both. i havent started the build quite yet so havnt decided
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Old 03-17-2010, 05:18 PM
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I would vote for the 2 bolt. Your really pushing the block to its limits. On the subject of your question you seem dead on. I would go for a mechanical roller in the 260+dur @.050" and the lift close to .700". This combo will be strictly strip and will of coarse be 13.0:1 and will want to see around 7000rpm so forged everything in the bottom end is a must
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Old 03-17-2010, 05:56 PM
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where can i find a cam with these specs? will it have to be custom? why does this make it a strictly strip though? will it run hot? burn lots of gas?
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Old 03-17-2010, 06:08 PM
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Quote:
Originally Posted by Hick_101
where can i find a cam with these specs? will it have to be custom? why does this make it a strictly strip though? will it run hot? burn lots of gas?
Okay I shouldn't say strictly strip, just impractical to run on the street. It will get horrible fuel economy and will require race gas.

My machinist has a 434ci sbc that has alum heads cr is 13:1 cam is about the specs i posted. Gets about 3-4 gallons to the mile. U will be in the ballpark of this. So if you can run around town with that and a 5000stall converter go for it. I know some crazy people that will do anything to say they have tried it so I won't tell you otherwise

I would say getting a custom ground cam will be the best approach. Tell them your setup and power goals and you get a package in the mail a week or so later.
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Old 03-17-2010, 06:58 PM
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Quote:
Originally Posted by zildjian4life218
I would vote for the 2 bolt. Your really pushing the block to its limits. On the subject of your question you seem dead on. I would go for a mechanical roller in the 260+dur @.050" and the lift close to .700". This combo will be strictly strip and will of coarse be 13.0:1 and will want to see around 7000rpm so forged everything in the bottom end is a must
Right on the money!!
Stack will be 9.0085", so cut block decks to 9.0085" block deck height for zero deck. Use Fel-Pro 1004 or equivalent head gasket for use with aluminum head.
I'm pretty sure this is the piston you'll be using...
http://www.summitracing.com/parts/HRS-HRC4581WL/
Brodix heads, part no. KCTI-227. Have heads milled by Brodix 0.036" for 62cc chambers and have them drill the steam holes required with a 400 block. Static compression ratio will be 13.0:1 with this combination. Double check with Brodix and tell them the pistons you will be using. Make sure they will be compatible with the chambers in the heads.
http://www.brodix.com/heads/track1.html
Use a solid roller cam with these timing figures....
http://www.compcams.com/Cam_Specs/Ca...?csid=342&sb=0
Note that this cam profile requires 7/16" rocker studs, so counsel with Brodix about this before you order the heads.
Counsel with the cam grinder. You may have to order a cam with reduced base circle to clear the connecting rods, or you may have to do some grinding on the rods. Talk with all your suppliers about this.
Use 1 3/4" primary tube, long tube, stepped race headers.
Use Victor Jr. single plane intake.
Use 950 CFM carburetor.

RPM HP TQ
2000 140 368
2500 220 463
3000 281 492
3500 351 527
4000 431 566
4500 514 600
5000 593 625
5500 645 615
6000 683 598
6500 702 567
7000 705 528
7500 693 485
8000 653 429
Peak volumetric efficiency 103.0 @5500
Peak BMEP 223.3 @5000

If you do decide to carry through with a motor like this, get on the phone to Milodon and find out what it's gonna take on the bottom end to hold it together. I've never built a 700hp production block, so I have no idea. I don't know if you can even make it work at all.
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Old 03-17-2010, 07:07 PM
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am i the one who said the quote you have, it looks familar and like my writing.

i certainly wouldn't want to run this motor on the street but it would be a beast at the strip.

pure strip cam
http://www.competitionproducts.com/H...fo/111113-06S/

strong street/strip cam
http://www.competitionproducts.com/H...nfo/111133-10/

these lifters would be good for either
http://www.competitionproducts.com/H...uctinfo/91119/

if you dont plan on making this an all out strip motor then i would try and get my compression down to about 11:1 and thus finding a cam that will work with this compression, i would also not worry about using a CNC'd 220 head, i dont think you would need the added expense of the CNC, you really wouldn't need quite 220cc either but i'm not sure i would go with a 200, maybe 210-215, (but at this level there isn't that much difference.

with the racing cam i suggested you would need a 4000 maybe 4500 at most, the street/strip cam you could get away with around a 3500-3800 stall, and you will probably want either in a small base circle for rod clearance.

i think i would use the 2bolt casting as they have proven to be stronger, but i would get a 4bolt splayed conversion set of mains like these

http://www.competitionproducts.com/B...uctinfo/MC103/

then i would probably put a gurdle in it like this one

http://www.competitionproducts.com/P...fo/PRW0940000/

i wouldn't want to go any higher in power than with the cams i mentioned above on a stock block and a 3.875 crank, if you want more power i would go after an aftermarket block

you are looking at around 8500-10,000 for this build
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Old 03-17-2010, 07:21 PM
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Quote:
Originally Posted by my87Z
am i the one who said the quote you have, it looks familar and like my writing.
Yep, post #14 here:
427 sbc
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Old 03-17-2010, 07:50 PM
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thanx tech1, i thought i remembered this post, i like that you ran the numbers on the dyno sim, i thought it would make about 640-660hp, and around 575ish tq. i like the 705hp @ 7000, and the 625tq @ 5000. i'm still a bit sketchy on whether a stock block will hold this kind of power, i'm not sure i would want to try, the extra 1500 for an aftermarket block would be well worth the assurance, especially when you are already spending 9K+
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Old 03-17-2010, 08:20 PM
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Quote:
Originally Posted by my87Z
the extra 1500 for an aftermarket block would be well worth the assurance
That's what I'd be thinkin' too....
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Old 03-17-2010, 09:13 PM
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yes you were the one that i quoted..sry didnt know i needed to ad your name. thx for the build options though
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Old 03-18-2010, 07:30 AM
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I also vote for an aftermarket block. Like 87z said if your block splits or comes apart or the webbing in the bottom rips out. There wont be much left of your rotating assembly. I would def say start shopping around. I know the rule of thumb for 350s is about 700hp for 4 bolts and 600-650hp for 2bolt but the 400 has wider journals which pushes the bolts closer to the pan rails. I have never built a 400 yet. Hopefully this summer. Maybe someone will chime in who has tried putting this much power to a factory block.
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Old 03-18-2010, 12:59 PM
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Quote:
Originally Posted by Hick_101
yes you were the one that i quoted..sry didnt know i needed to ad your name. thx for the build options though
no man, no need for that, i just knew it looked familar
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Old 03-18-2010, 01:00 PM
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Quote:
Originally Posted by zildjian4life218
I also vote for an aftermarket block. Like 87z said if your block splits or comes apart or the webbing in the bottom rips out. There wont be much left of your rotating assembly. I would def say start shopping around. I know the rule of thumb for 350s is about 700hp for 4 bolts and 600-650hp for 2bolt but the 400 has wider journals which pushes the bolts closer to the pan rails. I have never built a 400 yet. Hopefully this summer. Maybe someone will chime in who has tried putting this much power to a factory block.

i would actually say more like 500-550 for a 2bolt, and 600-650 for a 4bolt (production blocks)
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