I'm picking up a 400sb this Saturday. It's complete but tired. I'm going to rebuild this motor to drop in my 69 Z/28. My question is, what works in and with the 400sb. I know my way around small blocks but have never played with the 400. This motor will be street/strip, leaning more to the strip. I'm currently running a 302sb, M20 trans and a 4.56 rear gear which works great when I have my foot in it. Thanks for any help you guys can offer.

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Bob 69 302 Z

I've got a 69 Z28 with a 400SB, and I love it. When I got it the car was setup for street/strip. I've been slowly making it into a pure street machine, and one of the last things I need to change is some engine parts. Mine engine is a 406 (.030 over), right now its running 11.7:1 compression, I've got a comp cams 292H hydraulic flat tappet, Edelbrock Victor Jr intake, TH400, Holley 850 DP, 3" exhaust,Hooker Super comp headers and GM 461X heads that have been heavily ported and flowed that have titanium valves. Believe it or not, the car idles great on the street. It goes like a banshee.

I'm going to replace the top end soon to tame things down a little for the street. I'm going to get aluminum heads and drop the compression down to 10.7:1 and get slightly milder cam. I'm also getting a dual plane intake with a smaller carb. I want to turn it into more of a torque motor, right now I've got more HP than I know what to do with. I have a timeslip for the car, 11.9 ET in the 1/4 with this engine. It's a great motor, shreds tires. If you want to see a really good 406 build up, check Chevy High Performance back in OCT or Nov. They did a bad to the bone 406 that had about 446 HP and 510 ft/lb of torque. It had 9.5:1 compression, a Comp Cams extreme energy 230/236 cam, Performer RPM intake, 750 CFM carb and Dart Iron Eagle heads (200CC runners). Very mean motor, and acts like a pussy cat on the street.

P.S. The Heads/Intake/ Carb are for sale.

1969 Z28, 406SB

[This message has been edited by Shawn (edited 01-21-2000).]

Some of the items specific to the 400SBC:

- Externally Balanced: Needs externally balanced balancer and flexplate/flywheel
- Siamesed cylinder walls: Needs heads/head gaskets with steam holes for the street.
- Watch out for small-chamber heads, big bore and stroke raise compression with flat tops and small-chamber heads too high for the street.
- Main bearing diamter is 2.65" vs 2.45" and 2.30" for other SBC, making crankshaft specific to this motor.
- Main bearing cap bolts are spread due to bigger main bore, so main caps are also different than other SBCs.
- Rods are only 5.565" long, whereas other SBC are 5.70" long. Pistons, however, have same compression height as 350SBC due to longer stroke, shorter rod combo.

These are some of the differences, but all in all the motors are dimensionally the same. These motors make tons of torque for the street. Good luck!!

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69 SSRS Frame-off Resto
81 Z-28 377ci Drag Car

I have a 406 also, but have yet to fire it up. One thing good to do with SB 400's is to go with the 5.7 rods. You'll need a piston specifically for this rod combo, but they are readily available all over.

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70 & 1/2 RS
SB406 & M20 4spd
9" rear

70 Malibu 350/TH400

Gold member #103
Driveline Technician

i have a 406 also,love it.like it was said,the 400 needs the correct head gaskets,and the heads also need the steam holes (350 heads drilled work too),fly wheel and balancer..030 over is about max boar due to the siamese cylinders.i run 9.5 comp.,486 lift comp.cam,torquer intake,750 v.sec. holley (modified) and run 13.5@103 w/2.73 rear(spinning)was told with 4.11's and slicks will see low to mid 12's....good enuff for me http://www.camaros.net/forum/smile.gif

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http://hometown.aol.com/dagwould1/
68 Camaro

[This message has been edited by DOUG G (edited 01-22-2000).]

[This message has been edited by DOUG G (edited 01-22-2000).]

My 400 is very close to the "Bad to the Bone" motor Shawn referred to. I used Speed-O-Motive's "406 Strong Arm" kit which gives you 5.7" rods, hyperuetectic pistons, re-ground cast crank, rings and bearings. It's a good kit and bargain priced. I used the Comp Cams Extreme Energy 274 cam and Edelbrock Performer RPM heads. It runs great and it's got tons of torque - great street motor.

Most of the SB Chevy preformance engine building books address the 400 - Lingenfelter's does a good job. They're worth checking out.

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Scott
'69 400SB, Richmond 5-speed
'99 HD Road King Classic

I agree completely, 400's are great! One thing to watch out for is crankshaft endplay. They tend to wear and get sloppy.

Regarding crankshaft endplay - my problem was not enough! I had to do the 600 grit sandpaper, oil, and a flat steel plate sanding trick to get it loosened up so I had endplay at all.

Of course, the real point is that on any performance rebuild you should take the time to check and properly set all the critical clearances.

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Scott
'69 400SB, Richmond 5-speed
'99 HD Road King Classic