I'm rebuilding a GSR head for my LSVTEC and i'm trying to figure out which valves to go with. I was originally gonna go with .5mm oversized manley valves but i plan to run pretty large cams so valve clearances might become an issue. So i've decided to stick with stock size, i just need to find out which ones i should use. The 99-00 SI valves are flat on the bottom and will yield more compression. Does anybody know how much more comp it gives?? And aftermarket vavles will yield more compression aswell along with better design for flow on the stem side. anybody use stock sized aftermarket valves? i wanna see if it would be worth it to go for those.

 

oversize is usually a bad idea on stock bore anyway. A good valve job is usually better. I'd run a smaller valve if I some how could. I am intrested to hear peoples reflections on aftermarket valves however, since they are an integral part of a motor that is often forgotten about.

 

Just use some good aftermarket stock size

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by MAX_CFM &raquo;</TD></TR><TR><TD CLASS="quote">Just use some good aftermarket stock size </TD></TR></TABLE>

Any particular brands you could recommend? Ferrea, Manley, SuperTech, REV, etc.??

 

The new design Supertech valves are suppose to be great. I have heard nothing but good things about Manley and Ferrea valves. I would go stock size for valve clearence issues. That and the fact I haven't seen gains for +0.5mm and +1.0mm valves on B-Sereis motors.

I haven't heard of the B18A2 flat vavle theory before. Anyone else care to share? Most aftermarket flat valves are only a tenth or two anyways.

 

i would also go with the stock size for "shrouding" issues on a stock bore setup.