This is gonna sound stupid, but how do i tell if my 400M small block is EGR or not, and what does EGR stand for?

 

EGR is Exhaust Gas Recirculation. Without a doubt, your 400 (no "M") is an EGR motor. As far as I know, all 400's and 351M's had this. Look for a vacuum operated diaphragm mounted on the back of the carburetor spacer. There's an exhaust gas crossover through the intake manifold for preheating the manifold. The EGR syatem takes some of this exhaust and feeds it into the intake during part-throttle and cruising to lower combustion temperatures and reduce NOx emissions. It really doesn't hurt anything to leave a properly functioning EGR system in place. The EGR valve is closed at idle and at WOT.

 

thanks alot for the info, that really clears things up, my only issue now is that i want to begin rebuilding the motor, and edelbrock lists intakes for my 400 that are EGR and non EGR, what do i choose if i want a real street performer, and why?

 

I'm afraid I can't help you much there. It depends on what you mean by "streep performer". I'll suggest you mosey over to the 335 Series forum and ask this question there. They don't talk about anything but these engines and what you can do with them.

 

Oops! Darn ergo keyboard....

 

 

im not saying remove your EGR and block it, but i will give you some info about EGR's

the diaphram in them WILL go bad soem time in your trucks life, then you will have a truck that will rev up and down all day long...

and when it recirculates E gasses back into your intake manifold it starts to corrode your intake valves, now does this do damage? ...probably not, but if you want a performance engine, you dont want your port and polished heads and new valves to have build up on em and restricting your flow...anymore than you absolutely have to...

if you DO want to remove it, its easy, get a new ghasket for it (or make it) and then cut out a peace of steel the same shape/size as the back of the EGR and place it over where it came from, you will need to drill 2 holes for this as well.

i dobnt suggest removal simply because of emmissions laws...had to say that.

edit: you will also have to retard timing, as this will change your mixture and cause a "ping" in your engine, 1 degree with usually do the trick.