I have a 98 suburban with a 350 vortec and was thinking of making it a 383 using the stock intake setup and ex. manifolds, tune on the pcm and still use the stock lift cam. I can't seem to find anything else on the net about anyone else doing this everything I find they are using carbs. Does any body know anything about this combo? Any info is appreciated, Thanks Frank96hd

GM Performance Parts makes a HT383 that is 49 state legal (they claim) that uses the stock computer (and does not required to be programmed). However, a custom tune might make even more power.

http://paceperformance.com/index.asp?PageAction=VIEWPROD&ProdID=184746

They list the cam shaft that they use for this engine and the torque numbers very good (435 ft-lbs). You could build a 383 and use the same cam. I think that the stock cam would be too small for the 383. IMHO, cam choice is important here with the longer stroke.

//2000CAYukon

383 crate motors are much more expensive than 350s. Performance and mileage are not that different, unless you need more grunt for towing. A 383 or bigger small block then makes a lot of sense, because the mileage will be much better than with a big block.

If you're machining your existing block and doing the assembly and install yourself, it's not that much more.