I currently have a stock 4 barrel intake with a holly 600cfm, I was wondering if I would see an improvement with a Pefrormer RPM or Edelrock Stealth intake?
I was also going to add headers to my 289-stock engine
and look at replace the stock rear-end (3.0) to a 3.73?
Thanks

 

You may notice a small increase in performance with the addition of the intake but it won't be an epic gain in power. If you have an all original setup and it is working well, I don't know that I would be messing with it too much. If it ain't broke......

 

The RPM manifold plus headers should get around 30 more hp. You will be able to feel it if the carb is right.

 

yeah i wouldnt waste the money on the regular performer. but people say the wieand stealth is a good choice (i have no firsthand experience) and i do know that the performer rpm is a good intake, and the performer rpm air-gap is even better. anything bigger than that is overkill for what your doing.

 

The thing about the air-gap I don't like is the poor driveability when not fully wrmed-up and the worse mpg due to the fuel not being heated before entering the engine.

 

Good to know about the air-gap. First negative comment ive heard regarding it.

 

the airgap is good if your running in the 300-400 hp range it almost works like a single plane manifold the way it acts thats why it does that...but here is the manifold i use on most all 289 302 street engines its a holman moody hi rise dual plane manifold good for up too 7000 rpm

http://i45.photobucket.com/albums/f5...1x4_hirise.jpg

 

eastten how does that intake compare to a performer rpm on a dyno?

part of the loss in low end umph in the airgap is cause the center web is notched - you could weld it up and regain a little on the bottom. i always thought a colder charge coming in made more power and more power equals a more efficient engine which would equal metter mpg....... or something like that?!?!?!

 

it has a powerband of about 2000-7000, thats why i like it its pretty wide and may not have all the low end of a stock performer or somethin but it is an improvement over the air gaps low end imo...

 

I would go with the Performer RPM. Stick with the Holley 600,since you already have it. Go with a set of Tri-Y headers, 2.5" exhaust with H-pipe and 3:55's (3:73's too much)and you'll have a nice street/strip car.