I have an extra pair of ported 243 heads with a burnt valve (on my GTO before I got the Trick Flow 215 heads). I was thinking about rebuilding and selling them since they have 2.02 intake valves. I assumed they were too big to fit in the 5.3 or at least would cause valve shrouding issues. I'm starting to see other people using 243 heads with this valve size.

First, I'd like to confirm a 243 head with 2.02 valve would fit with no interference and second how much performance it'll gain me. Hopefully people that have actually done this will chime in.

They have excellent flow numbers (ported by PM-FL) and are currently milled to 62cc, but I could easily mill them a bit more when I replace the valve and have the heads freshened up. They also currently have low mileage Patriot Gold dual springs with titanium retainers.

Been thinking of doing a cam swap. If these heads will work good, might as well do everything at once.

 

Been reading past threads and found several posts that say they used 2.02 intake valves in 5.3 motors. Found a number of posts that stated the larger valves cause shrouding. Even found a photo showing someone measuring heads with 2.02 valves using digital calipers which indicated about .030" of clearance with the cylinder wall.

Then I found this post:

 

my PRC heads have 2.02 valves

 

2.02 valves is what I would do.