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400 sbc build tell me what you think

3K views 13 replies 7 participants last post by  Chevrolet4x4s 
#1 ·
the engine is a early 70s 400 sbc 509 casting .30 over
with rhs 64cc vortec heads with 170cc runners
cam lifters rods pistons from a summit kit saying this engine should build 350-375 horsepower (with everything else stock)
cam has hydraulic lifters with roller rockers on top the heads
offenhauser intake i believe is a single plane
10.5-1 compression ratio

and looking to run nitrous does all this seem to be able to hold a 150 shot for weekly drag and occasional driving

also cfm carb should i use for this setup thinking with the nos a 750 or 800?

85 buick regal considerably stripped out is going to be the recipient
 
#4 ·
You can contact various nitrous company`s that will tell you how high you can go. with a dome hyper piston on race fuel I wouldn`t go over a 100 horse shot. Make sure you have a top notch ignition system from the point of ignition to the plus. Nitrous hit`s the intake at minus 128 degrees so a hotter spark is recommended. You`ll also have to retard the timing slightly with nitrous use.
 
#13 ·
Chevrolet4x4s said:
Am I going to run into problems with harmonics in my vortec 406 :sweat: ? Internaly balanced crank,Its at the machine shop now having the rotating assembly balanced :sweat: .
Shane
Use an 8" neutral balance damper from a 350. Here's a rebuilt one for 33 bucks from Damper Doctor that uses a 2:00 O'Clock timing tab....
http://www.damperdoctor.com/Merchan...ode=DD&Product_Code=CHE3501&Category_Code=CHE
and here's the same thing for use with a 12:00 O'Clock timing tab......
http://www.damperdoctor.com/Merchan...ode=DD&Product_Code=CHE3051&Category_Code=CHE

Use a toothpick to apply yellow paint into the TDC groove on the outer damper ring so you can see it easily with a timing light.
 
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