Is the newer speed density system able to support 406cid, high rpm(7200), high horsepower(525+)? I would like to use a 406 in my 85 vette, and wondering if speed density is capable of supporting it or possibly some form of "stand alone" system? What would be the best? what all would I need to get for this change over? Is there any specific year or manufacturer? I've got plans for homemade short runner intake, just not sure if speed density will work. What are "stand alone" systems, and how do the measure airflow? If you have a combination that is close in rpm/hp range, what type of system do you use? Thanks for all the help. I'm a newbie, and I'm really enjoying "CF.", as well as my vette. :seeya :cheers:

 

Speed density is better for high HP applications, so if youre planning on more than 450-500hp then it wouldnt be a bad idea.

 

I would say that speed density or aftermarket ecm is mandatory for 525 hp. You don't really need to spin 7200 rpm to get 525. I suspect that you'll get there at around 6000.

Be prepared to do some tuning on a dyno for speed density at different power levels to zero in the fuel tables.