1.7 Rocker questions

[RTStork]

For those of you running the 1.7's, I have a few questions. What kind of power gains can I expect? When driving normal, will my gas mileage be lower than stock? Do they fit under the stock valve covers ok?

 

[Paul Gagnon]

Your engine comes with 1.7:1 rockers from the factory. Changing to a 1.7:1 rocker is a big deal for small block Chevys because they come with 1.6:1 (or is it 1.65) rockers.

 

[RTStork]

I thought it had the 1.6's like the 5.0L Mustangs. I guess I was wrong. Thanks!

 

[Paul Gagnon]

oops I made a mistake. Sorry I was had just gotten out of bed when I posted that.

You have 1.6:1 ratio rocker arms. According to what information I can gather you may need to get taller valve covers or modify yours for clearance. Check with some of the camshaft manufacturer websites and the Ford Racing site.

Also stock Chevy's usually have a 1.5:1 rocker arm ratio.

Sorry for the confusion.

 

[RTStork]

No problem about the confusion. I know some of the guys are using them, so I hope they see this and reply.

 

[drnaline]

mutiply

If you have stock exhaust your not going to notice much. What your doing is incresing lift without changing duration. The more flow you get with your setup(intake and exhaust) the benifits with multiply to a point. Then you will smack a wall and have to change cams to gain any more. Its a good way to see if a cam change is warranted. You might even play with splitting them up. Like using the 1.7 on the exhaust. That will tell you if your setup wants more duration. Run down to Autozone and buy Desktop Dyno, like forty bucks. Play around with the cam specs and see what happens. Theres alot better explanation for it, but thats how I understand it. I think its Comp Cams or one of those guys that has a pretty comprehensive libriary and explain its alot better than I.

 

[RTStork]

I have a dual exhaust. Thanks for the reply. I hope some of the guys that are running the 1.7's will reply. I can then hear the gains, without any doubts.