When GM gets the specs for the LT4 cam, they use 1.6 rockers. Are the early (1993) LT1 cams also rated with 1.6's?? Because the LT1 cam I have the specs for has .450 lift. If thats calculated with the use of 1.5 rockers, then by adding 1.6's, I'd get the same lift as an LT4.
Now, assuming the difference in the LT1 and LT4 cams mainly lies in the use of diferent rocker arm ratio's, if I used an LT4 cam with 1.5's (.450 lift), could I still use stock valve springs in my LO3?

 

also, these stock valve springs have over 100,000 miles on them. Can I use them with an LT1 cam?

 

the duration is different also. can you use your stock springs? for a little while. won't get full potential of the cam. also might wipe the cam from too little pressure. or kill a lifter.

 

92RS,

There were several cams installed in the LT1s, and at least two different LT4 cam grinds"



Be careful to check what you're paying for.

 

Vader,
I did a search before i made this post, I already found your chart, it was real helpful. But Do you know if the only cam that used 1.6 rockers was the 1255112 LT4 cam? Take another look at the chart, primarily the 93-95 F body cam. IF that had 1.5 rockers when those specs were calculated, then the by using 1.6's with it, you'll get a cam similar to the LT4. 202/207 and .450/.450 with 1.5 rockers should turn into 205/210 and .480/.480. As you know, the 116* lobe separation doesnt change. But do you see what I'm getting at?

93-95 LT1 cam with 1.6 rockers= 205/210 @ .050, .480/.480 lift

96 "Y" LT4 cam with 1.6 rockers= 203/210 @ .050, .476/.480 lift

I can obtain the LT1 cam much easier and cheaper than the LT4, and if my calculations are correct, it's really nothing special anyway, since the rockers make the difference.

What are your thoughts on this?

 

rocker arms do not change duration. only lift. duration is ground into the cam. the lift numbers are at the valve. not the cam.

 

94-96 350 "B" body 191*, .418 int., 196*, .430 exh. 111* LS
94-96 350 "B"w/1.6 194*, .446 int., 199*, .459 exh. 111* LS

I had always thought that rocker ratio's only alter the total lift. I was told I was wrong. I'm only going on what people tell me, but I don't make cams. I really don't know, but it just looks to me like the rocker ratio has an impact on duration in that chart.

 

and they put a different cam in it when they also put the 1.6 rockers. look at the cams for the '95 cars. you'll notice 2 different part numbers for the cam.

vader - how can the 95 f body with 1.6 rockers have the same part number cam as the '96 right under it but have different LSA? that can't change either with rocker arms.