Im doing minor mods to my g/fs 90 Firebird. I'd like to do a very mild cam. Do you guys know what the factory lift is on the cams for the 5.0 vin "E" TBI's? I thought maybe and easy way to do this would be to step the ratio on the rocker up a notch. Is the stock ratio 1.5? If so I figured on purchasing some 1.6 Rollers. Has anyone done this? What kind of lift will it gain? Will this hurt the valvetrain? Thanks!

 

Its an easy swap, there will be plenty of clearnce room. The stock cam is a joke, something like .380 lift, or something really sad like that, it really isn't much of a cam at all.

 

A 1.6 rocker swap as shown great gains on these cars. Some people (user names escaoe me now) have dropped a full tenth off of their ET with this swap. The 1.6 rockers really help cylinder fill with the stock cam. I would not opt for the fancy full bodied roller units. Instead I would look at the stamped rockers with roller tips that are roughly just under $100.

 

so this should put the lift around .400 lift or about what should I expect? To me doing this just really beats putting a cam in....if it was my car yeah I'd be pulling the cam but its my girls and she isnt as much of a motor head......not yet anyway ....so I would love to opt for the 1.6 Rollers.

Do you recommend any part numbers Shifty?

Just like some Summit Racing specials??
Why do you advise to not go with the full bodied roller rockers? I am very curious about this.

 

Also does that thing have 3/8" studs or 7/16"?

Do you guys adjust them like I do my Ford? Top of lift....down hand right then half a turn? I dont know if GMs are different or not...like I say this is a learning experience for me.

 

Part number escape me right now but I do know summit makes a set and I belive Proform does as well.

Check the LT1 cam digest above for proper valve trian adjustment. It is described towards the bottom.

To figure our your new peak lift take the old lift value and devide it by the current rocker ratio; .380/1.5 = .253. Now multiply it by the new rocker ratio; .253*1.6 = .405

 

Cam is worse than that.

10088155* .350 .384 179 194 109.0 (108/-112)

Made me want to die inside when I read that.