Max O/S intake valve for GS1000 8v stock seat?

[Addy Leung]

May anyone would like to tell the max over size intake valve to be installed on the GS1000(8v) stock valve seat?
I only konw the stock size intake valve is 38mm.

[TheCafeKid]

May anyone would like to tell the max over size intake valve to be installed on the GS1000(8v) stock valve seat?
I only konw the stock size intake valve is 38mm.

Its been my understanding from ALOT of reading, no real world testing, that the valve sizes used on the 8v motors were so generous from the factory, that no oversized valves need to be used for even the most extreme mods used. Commonly, again from my reading, they would perhaps at most use high grade valves in the same size, and the usual port, polish, heavy duty springs, and hotted cams, along with bore kits. Someone with practical experience may know more...

[chef1366]

May anyone would like to tell the max over size intake valve to be installed on the GS1000(8v) stock valve seat?
I only konw the stock size intake valve is 38mm.

What's the plan?

[Addy Leung]

I will have a GS1000.
I collected a set of webcam Valve-springs and yoshimura 1mm O/S valves.
Plan to have basic port to the head and may be a set of mild cams and 73mm big bore kit.
Just want see over size intake valve needed or not?
it is a long time project to collect all the parts because $.

[Nessism]

Better budget for some crank welding as well.

[chef1366]

If you have the valves and a machinest I say go for it.
It'll take more gas. Fun times jetting is in your future.

[Big Jay]

Its been my understanding from ALOT of reading, no real world testing, that the valve sizes used on the 8v motors were so generous from the factory, that no oversized valves need to be used for even the most extreme mods used. Commonly, again from my reading, they would perhaps at most use high grade valves in the same size, and the usual port, polish, heavy duty springs, and hotted cams, along with bore kits. Someone with practical experience may know more...

They go clear up to 48 mm intakes in Pro Stock.

If you have the 1 mil oversize, go for it. Hope your machinest knows there is way more to installing oversize valves than just cutting a larger 45.

Jay

[TheCafeKid]

They go clear up to 48 mm intakes in Pro Stock.

If you have the 1 mil oversize, go for it. Hope your machinest knows there is way more to installing oversize valves than just cutting a larger 45.

Jay

Thanks for the enlightenment! I have never really delved into all that is done on drag motors, I stupidly assumed he was talking about common street HP upgrades. But, i suppose one could make the argument that by the time some of the drag guys are done with those motors, there isnt much that IS stock left on em lol..

[rapidray]

If you don't have a head builder in mind yet PM me & I'll help you out. FIRST... WELD the crank! Then, if it were mine, I would go 1 mm over intakes, stainless both sides, good springs & Ti retainers, bronze guides, radiused valve job, MILD porting, Web 110 grind cams(.395 lift with 256 duration @ .050 inch lift), & a 1085 piston kit with the compression about 10.5 to 1. This head & pistons with 33 smoothbores will make an AWESOME hot street/strip engine! Definitely capable of 9 sec quarter with the right chassis setup & light rider. Plus, it is a design that will make good power & be low maintenance if treated correctly! Let me know if I can help. Ray.