I am intending on placing a 3.0L CIS system on a punched out 3.1L corvair engine. My desire is to have better fuel economy and better low end torque. I can pick a com for the better low end, but I am not sure what cam I need to consider for the CIS. So my question is, would a cam designed for a turbo be smoother than one designed for carbs alone?
The 260 grind cam I am looking at is a good street cam with low end tq like I want and is mild, but it is also recommended for the turbo motor.

I am far from an expert, but my understanding is that CIS doesn't like valve overlap, which it causes pulses in the intake and disrupts the airflow meter.

That is correct, but I know nothing about how much and if a turbo cam has overlap typically, or if I should even care. I can put the specs up if that would help, but I go to dig them up first.

Again, I am far from an expert, but my understanding is that turbos typically do not have valve overlap because of the back pressure of the turbo impeller.

That is my assumption

Look at the profile for a 964 cam. People have put those into 2.7 and 3.0's with CIS. I guess they work really well and add umhf!

I guess I could have done that, I put SC cams in my 2.7 CIS rebuild after all (duh) I forgot about that.

Um the CIS is from a 3.0 SC

the Corvair is a 3.1

so um how about a 3.0 SC grind

Oh sure, I will put an SC grind on the CORVAIR cam......OR, I could just buy a good new cam that is not gonna be a hassle

Eat me, poon magnet

Chim Chim not like you. Go back in you hole susage grinder.

You could have John Dougherty regrind the cams, he did mine for $275. I got his DC19 spec for my '81 3.0 CIS motor.

www.drcamshafts.com

964 cams were in the Rocket....BIG diff and mpg actually improved.

A turbo cam would be better for CIS. Turbo motors don't like a lot of valve overlap, as it allows all that boost to blow out the exhaust. CIS doesn't like a lot of valve overlap, as it makes the air meter flutter and cause mixture problems. That's why the 930 used CIS. It works great with Turbo motors.

I would suggest you use both. Get a corvair turbo setup and use the CIS with it.



And as for the SC and 964 cam suggestions... how were you going to use cams from a 911 in a Corvair motor? The Corvair only has one cam in the case, and the 911 has two overhead cams.....

I was being a smart ass about the SC cam in the corvair engine, and I was only talking about the profile being put on a corvair cam (tongue in cheek).

The 260 grind corvair cam will do well for my purposes. I dont want to turbo it, though

Thanks for all the explanation fellas.