Preparing a 400 ci bloc
Thread Starter
Intermediate
Joined: Mar 2007
Posts: 32
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Preparing a 400 ci bloc
I would like to change my 350CI in my 1979 french corvette with a 400CI engine.
I would like to know if there is someone who has ever changed the engine with a 400?
I would like also to upgrade this engine. What sort of changements can i do :
Specific Pistons in order to lower the compression ratio?
Cylinder heads AFR 195?
750 cfm Carb?
What sort of cam?
performer rpm airgap?
What esle?
I would like to know if there is someone who has ever changed the engine with a 400?
I would like also to upgrade this engine. What sort of changements can i do :
Specific Pistons in order to lower the compression ratio?
Cylinder heads AFR 195?
750 cfm Carb?
What sort of cam?
performer rpm airgap?
What esle?
Burning Brakes
Joined: May 2007
Posts: 945
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From: Ventura California
I haven't done a 400 but I can tell you just to make sure you have the steam holes in the heads and head gaskets if you use aftermarket heads. Most will require you to drill your own steam holes in the head.
Team Owner
Joined: Oct 2004
Posts: 23,831
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From: Springfield MO
St. Jude Donor '07
Le Mans Master
Joined: Dec 2006
Posts: 5,557
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From: Oquirrh Mountains
St. Jude Donor '09
400 SB Build
Make sure you use the right balancer and flexplate/flywheel since it's an externally balanced engine. Ditch the 5.56 rods for 5.7" rods. Check clearance between rod shoulder and camshaft. If using a 2-bolt block, install high-strength fastners; because the 2-bolt caps tend to walk under higher RPM conditions (or install 4-bolt caps on #'2, 3 & 4). Somebody already mentioned steam holes - but be sure the gaskets have them also. Oh, make sure and have the rotating assembly balanced.
Gotta know more on your intended use - street, Nitrous, forced induction? Expected hp/performance/rpm range, etc. for parts recommendations.
-Lurkin
Gotta know more on your intended use - street, Nitrous, forced induction? Expected hp/performance/rpm range, etc. for parts recommendations.
-Lurkin
Last edited by Ben Lurkin; Sep 28, 2007 at 11:09 PM.
Melting Slicks
Joined: Mar 2005
Posts: 2,838
Likes: 10
From: Austin TX
If the engineers at GM thought steam holes were needed for Grandma's Caprice, you can bet they're needed once you start adding HP. Otherwise coolant converts to steam in the hot-spots between cylinders and detonation becomes a problem.
Good advice on the rods above.. Also, if you don't have a 400 crank, flywheel and harmonic which are all externally balanced, Scat makes an internally balanced 400 crank which is preferable. But if you find a good shortblock, use C, F, & H from it and save some cabbage (chunk the rods and pistons as stated above).
I don't think you can get heads that are too big for a 406. I'd forget the 195's and go to something in the 215cc range. Also, I'd go with 1-3/4" headers,..not the smaller 1-5/8".
Also, good 400 blocks are getting tough to find,..they can only be bored once and then it's time for sleeves. So be careful when searching out a block. It's said that the 2-bolt blocks are stronger but just worry about getting good std bore crack-free block.
The cam choice would depend on your goals, tranny, and gears out back.
Great choice, the 406. I run one in a 3000 lbs 69 Camaro and it's a blast!
Good luck!
Good advice on the rods above.. Also, if you don't have a 400 crank, flywheel and harmonic which are all externally balanced, Scat makes an internally balanced 400 crank which is preferable. But if you find a good shortblock, use C, F, & H from it and save some cabbage (chunk the rods and pistons as stated above).
I don't think you can get heads that are too big for a 406. I'd forget the 195's and go to something in the 215cc range. Also, I'd go with 1-3/4" headers,..not the smaller 1-5/8".
Also, good 400 blocks are getting tough to find,..they can only be bored once and then it's time for sleeves. So be careful when searching out a block. It's said that the 2-bolt blocks are stronger but just worry about getting good std bore crack-free block.
The cam choice would depend on your goals, tranny, and gears out back.
Great choice, the 406. I run one in a 3000 lbs 69 Camaro and it's a blast!
Good luck!
Last edited by 73, Dark Blue 454; Sep 30, 2007 at 10:34 PM.
Thread Starter
Intermediate
Joined: Mar 2007
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It's OK for the steam holes, i will have a look seriously before buying it.
I 've read also the fact that it is very important to have Rods, pistons, crank, flywheel, clutch balanced together.
I would like to use this engine for car races, runs.... and street.
The standard 400ci delivers low HP : 180 hp.
Is it easy to develop the HP by cams, heads, headers, carb....
What do you recommend me for this use?
I 've read also the fact that it is very important to have Rods, pistons, crank, flywheel, clutch balanced together.
I would like to use this engine for car races, runs.... and street.
The standard 400ci delivers low HP : 180 hp.
Is it easy to develop the HP by cams, heads, headers, carb....
What do you recommend me for this use?
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Thread Starter
Intermediate
Joined: Mar 2007
Posts: 32
Likes: 0
I hesitate between 2 kits so as to rebuild my 400 engine. I don't want to ad nitrous nor compressor. I just want to have fun with Hp :
http://www.cnc-motorsports.com/produ...207&CtgID=9005
http://www.cnc-motorsports.com/produ...00&CtgID=20652
Can you tell me please what you would choose?
http://www.cnc-motorsports.com/produ...207&CtgID=9005
http://www.cnc-motorsports.com/produ...00&CtgID=20652
Can you tell me please what you would choose?
Intermediate
Joined: May 2007
Posts: 28
Likes: 0
From: Bakersfield California
Bigger is better. If you go the 434 get a 2 bolt block and have splayed caps installed. You will need BIG heads to feed it as well as a BIG intake manifold. The heads you want probably will not work with sidepipes. The BIG heads need valvetrain that costs BIG money. Get an internally balanced rotating assembly if you can. Regardless, run as long a rod as you can. Stay with a 2 bolt block and stud it if you wont put the splayed caps on.
C6 the C5 of tomorrow
Joined: Nov 2000
Posts: 6,665
Likes: 2
From: Twin Cities Minnesota
I built my 434 way back in '99, internally balanced.
All the details here;
http://temp.corvetteforum.net/c3/427v8/engine.html
If I were to do it agin, I would build a 406, a lot easier, a lot cheaper, just as powerfull.
Keith
All the details here;
http://temp.corvetteforum.net/c3/427v8/engine.html
If I were to do it agin, I would build a 406, a lot easier, a lot cheaper, just as powerfull.
Keith
Thread Starter
Intermediate
Joined: Mar 2007
Posts: 32
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According to you, it would be better to use these spare parts :
- New Scat 9000 Series Cast Crankshaft ,
- Scat 4340 Forged I-Beam rods with ARP 3/8" Cap Screw Bolts,
- Forged Probe or Keith Black Dish Pistons,
- Piston ring upgrade will be Total Seal Classic Race Plasma Ring Set,
- Bearing upgrade will be Clevite 77 H Series Rod and Main Bearings,
- Internal Balaced Kits,
It called : SB Chevy 407 Scat Rotating Assembly Kit, 3.750 Stroke 6.000 Rods 10.3:1 Forged Dish Pistons.
- New Scat 9000 Series Cast Crankshaft ,
- Scat 4340 Forged I-Beam rods with ARP 3/8" Cap Screw Bolts,
- Forged Probe or Keith Black Dish Pistons,
- Piston ring upgrade will be Total Seal Classic Race Plasma Ring Set,
- Bearing upgrade will be Clevite 77 H Series Rod and Main Bearings,
- Internal Balaced Kits,
It called : SB Chevy 407 Scat Rotating Assembly Kit, 3.750 Stroke 6.000 Rods 10.3:1 Forged Dish Pistons.
Le Mans Master
Joined: Sep 2001
Posts: 7,739
Likes: 630
From: Unreconstructed, South Carolina
Have you got a 400 block? Has it been thoroughly checked and measured by a pro experienced w/ sbc? Must do that before any parts order.
first read this 406 buildup (impersonator I)
http://chevyhiperformance.com/techar.../148_0306_406/
then read the followup (impersonator II)
http://www.chevyhiperformance.com/te...imp/index.html
first read this 406 buildup (impersonator I)
http://chevyhiperformance.com/techar.../148_0306_406/
then read the followup (impersonator II)
http://www.chevyhiperformance.com/te...imp/index.html
Last edited by jackson; Oct 6, 2007 at 10:51 AM.
Tech Contributor
Joined: Aug 1999
Posts: 14,376
Likes: 6,375
From: At my Bar drinking and wrenching in Lafayette Colorado
Just a minor detail on the 400: Most 400 blocks do not have the holes drilled in the front driver's side of the block for the power steering pump bracket. You have to place the bracket on the block, transfer punch the hole locations, and drill & tap the block for the bracket. Many blocks also do not have the hole drilled and tapped for the clutch Z-Bar attach point if your Vette is a 4-speed.
Other than that, the advise given above is good: Go with the long rods, good heads, and a lot of cam. You'll make plenty of power with a 406.
Other than that, the advise given above is good: Go with the long rods, good heads, and a lot of cam. You'll make plenty of power with a 406.
Race Director
Joined: Apr 2000
Posts: 17,676
Likes: 201
From: Who says "Nothing is impossible" ? I've been doing nothing for years.
According to you, it would be better to use these spare parts :
- New Scat 9000 Series Cast Crankshaft ,
- Scat 4340 Forged I-Beam rods with ARP 3/8" Cap Screw Bolts,
- Forged Probe or Keith Black Dish Pistons,
- Piston ring upgrade will be Total Seal Classic Race Plasma Ring Set,
- Bearing upgrade will be Clevite 77 H Series Rod and Main Bearings,
- Internal Balaced Kits,
It called : SB Chevy 407 Scat Rotating Assembly Kit, 3.750 Stroke 6.000 Rods 10.3:1 Forged Dish Pistons.
- New Scat 9000 Series Cast Crankshaft ,
- Scat 4340 Forged I-Beam rods with ARP 3/8" Cap Screw Bolts,
- Forged Probe or Keith Black Dish Pistons,
- Piston ring upgrade will be Total Seal Classic Race Plasma Ring Set,
- Bearing upgrade will be Clevite 77 H Series Rod and Main Bearings,
- Internal Balaced Kits,
It called : SB Chevy 407 Scat Rotating Assembly Kit, 3.750 Stroke 6.000 Rods 10.3:1 Forged Dish Pistons.
Team Owner
Joined: Oct 2004
Posts: 23,831
Likes: 10
From: Springfield MO
St. Jude Donor '07
Team Owner
Joined: Aug 2006
Posts: 24,125
Likes: 15
From: Columbia Missouri
Hose them how? The material you're drilling through is not that thick and it's an open cavity under the hole. Mark the spot with a punch, drill a small pilot hole and then follow with a 1/8" bit. It went super easy when I drilled my two heads for my 400. I just don't see how drilling the hole would harm them.
Last edited by Durango_Boy; Oct 6, 2007 at 05:42 PM.