Is there an amount at which a production block will crack? I was planning on building a 550hp motor n/a and then put about a 200 shot behind that. Does anyone think that the block will hold?

Thanks
Jeremy

 

I would drop down to a 125-150 shot of N20.....then it might hold if u built it right...whats your budget?

 

Probably in the $5k area. I know the rotating assymbly will all be forged, I just heard that you cant put out much more then 700hp before you have problems with the block.

 

I say push it till it breaks, if you can put a 350 shot of nitrous on a stock small block chevy 350, you can put a 200 shot on a 550hp 400 block if you have a strong enough rotating assembly, and the right A/F mixture, the right type of fuel and the right ignition timing.

 

With the siamesed cyliders the 400 block can't take as much as a 350 block. If you go over .040 overbore you'll tend to run hot where as a 350 can take a .060.

I'd say if you're running the stock bore to maybe .030 then it should be able to handle what a 350 would. I'd still suggest talking to someone at a good engine shop.

 

If O-Town means Orlando Florida, call Dave over at CRE

CRE MACHINE (407) 649-1789
1017 W CHURCH ST
ORLANDO, FL 32805

If they don't know, nobody will know

 

Is the 400 a 2 bolt main or 4 bolt main? From what i've read the 4 bolt mains are weaker and can crack by the cylinder even with a .030 overbore.

 

Nitromethane: Nope O-Town stands for Olathe, KS, but thanks for the reference.

BlowBye: The motor is a 2 bolt, atleast I think havnt had it apart. My friend that I am buying this one from, he almost bought a 4 bolt, but I told him to look for the 2 bolt blocks.

 

Sounds like a decent block then. Id go with the miloden Billet main caps or even a girdle if you're gonna throw all that hp and torque. Make sure you dont overbore and good luck.

 

This is my .02 cents
1. Bottom end use Splayed Main Caps w/ ARP Studs good for about 750hp
2. If you go over .040 overbore you'll tend to run hot where as a 350 can take a .060
False, the reason that SBC 400 was overheating because people would change cylinder heads and DID NOT drill the steam holes. Use a Fel-Pro 1014 Gasket which have the steam holes. Also a good idea is to plug the tap two big holes in the middle of the deck and have the plug with pipe fitting. The hole close to the intake must be drilled at an angle (I think 22*, dont quote me) This is a must when you remove the stock 400 heads, which really sucks.
3. Cylinder Wall was different in every 400 block and the only way to tell if you have enough meat in the cylinder is to have the block Sonic Check, Money well invested.
4. When getting you machine work done ensure that you have the block deck plate hone, this induces the stress that cylinders head installation incurs. You will get a much rounder, gas tight bores when the engine is assemble.
5. Make sure that you have the entire rotating assembly professionally ballance.

Here is my Combo SBC 408

SBC 400
(4.165 bore X 3.750 stroke)
Crank: Scat 9000 3.750, Internally Balance
Piston Wiseco Pistons .040, Flattop 5.4cc,
Compression: Static-10.48:1; Dynamic: 8:30:1
Rods: Eagle H Beam 4340 forge Rods 6.0
Block: Zero Deck: 00.000
CAM: Ultradyne
280/288 110 .525/.540 247/255@.050 Pro-Street cam,
Heads: AFR 195 23º valve angle, 74cc, and drilled steam holes.
Head Gasket: Fel-Pro-1014 / 0.039
Intake: Torker II
Carb: Holley 750 (3310)

David