I just got a 2005 5.3 engine with 706 heads and 97K miles to put into my 72 Chevelle. Since it is sitting on a stand I thought about swapping the cam before I put it in the car. I found a good deal on a Lunati cam with the following specs:
Duration 214/218
Valve lift .555/.551
LSA 117.5
Unfortunately no part number on it. I want to keep my mpg's but get a little HP boost since it will be a daily driver. Anyway, would that be a viable cam or would i need to do heads or at least valve springs to do the swap?
Just want some feedback.

 

For that amount of lift, the stock springs won't cut it. You would need at least some "Z06" valve springs but those can be had cheap($60/set). They are good up to about .570" IIRC.

I would consider that the major difference between a LS1 head and 862/706 is intake valve. Yours are about 1.89" and the LS1 heads are 2 inch. For about $100/head you could take them to a machine shop and have them milled about .030" for increased compression(half a point or so?) and have them cut for LS1-style valves. Would give you more power and breathing room.

See this article. It is mostly stock GM cams but includes a couple of Comp cams as well. It shows you what you can do with a basically stock 5.3. The HP/TQ numbers are at the crank so keep that in mind when comparing wheel numbers of some others, but still eye opening every time I read it re: just how much power you can get out of a basic 5.3.

http://www.hotrod.com/how-to/engine/...st-comparison/

The "hotter" of the stock LS1 cams IMO is a good, cheap way to make the 5.3 more of a "car" engine...it's the exact direction I was headed before I yanked the 5.3 in favor of an LS2.

Hope this helps.