c5z28

iTrader: (11)

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

006rcsb

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

Mark Johnson

iTrader: (1)

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......................

brent5631

iTrader: (7)

Some ported 5.3 heads would be better for sure.

c5z28

iTrader: (11)

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.

1FastBrick

iTrader: (17)

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.

swift700

iTrader: (3)

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.

swift700

iTrader: (3)

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.

swift700

iTrader: (3)

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.