I have supposedly seen heads with a 2.00 intake valve fit on the 5.3 bore, but I am curious to know if 2.02/1.6 valves will fit on a 5.3 bore. If the cylinder walls need to be notched that's fine but if you can post a link since this would be something new to me. Thanks for all help

 

the prc stg 2.5 5.3 heads have 2.02/1.575 valves in them

http://www.texas-speed.com/shop/item...id=84&catid=40

 

Hmm, i know most everyone goes 2.02 intakes after machining. That brings up another question; what's better- wome outta the box 243's or some 5.3 heads that have been CNC'd by like TEA......................

 

Some ported 5.3 heads would be better for sure.

 

The question is regard to some Absolute speed heads that have already been ported milled to 58cc and have the valves I stated above. They made 455rwhp and 405rwtq with a vengeance cam on an ls-1 for anyone who is curious. Don't care about brand just curious if they will fit the bore with the specs they have.

 

I Have a feeling they would fit but since a 2.00 Valve starts to shroud in a 4.8/5.3L Bore on a flow bench. I can only Imagine The problem would be more obvious with a Larger valve.

 

I just posted a similar question over on the LS1 site. I have a set of 243 heads with 2.02/1.57 valves that I'm thinking of putting on my 5.3. After measuring across the valves the width is 3.720 from one valve across to the other valve. In a 3.780 bore that leaves .060 or .030 from the edge of each valve to the cylinder wall. That is if everything lines up perfectly. I seems really tight but I'm not sure what an acceptable clearance is. I'm waiting for someone more knowledgeable to chime in and offer an opinion.

 

Here's a pic of the 2.02/1.57 valves showing the measurement.



I might just notch out the cylinders for these valves. I will decide today as I'm going to start my blower installation.

 

This is a fairly common practice for tight valve-to-cylinder clearance. I lifted this pic from another site but it shows the reliefs ground in:



I think this is what I'll do for the added clearance safety margin. It also improves flow by unshrouding the valve somewhat.