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a 272 is one of them poxy ass hks cams though...youd want something like a 270 from tomei :laugh:

me personally i wouldnt go any lower than 270 10.25, i've be more inclined to go with the 10.8, depends on the rev limit too though

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Mine has Jun 272 / 10.5 inlet and 280 / 10.8 exhaust. I didn't fit larger exhaust valves to this head and the longer exhaust duration and higher lift is there in an attempt to compensate for the standard mismatch in valve sizes.

Cheers

Gary

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so going the larger lift is fine?

Why do you think it might not be fine?

Plenty of clearance to the piston crowns, if that's the question.

i thought it might get to crazy

Too crazy for what?

The extra 20% capacity of the 3 litre makes smooth what feels like lumpy cams in a 2.6.

im happy to go larger if need be

More lift won't hurt, but I wouldn't be going for more than 272/280 duration, the RB30 doesn't need the rpm range that longer duration would provide.

is it worth mixing up the overlap?

An often argued question, for which I don't believe there is one correct answer. I only went for the longer duration so that I could get the higher lift on the exhaust cam as I know the exhaust valves are too small in proportion to the inlet valves. For the RB25.5 I used larger exhaust valves with the same lift and duration cams on both inlet and exhaust.

Cheers

Gary

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sounds like 270 10.8 lift both sides

ill be upgrading valves all round

head guy said 10.2 lift is easy and when you go 10.8 it gets alot tighter( eg more bucks! mainly due to more work and more expensive springs becasue of potential bind and rates)

anyway bigger is better and faster

hopeully all teh head work will fully utalise the gtrs's

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What is the limiting factor stopping you going bigger?

other then having no lift available bigger then poncams 260 for NEO i was also told by spool who is using same head. Cant exactly remember how he explained but its the way the Head is design. You think they are too small?

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other then having no lift available bigger then poncams 260 for NEO i was also told by spool who is using same head. Cant exactly remember how he explained but its the way the Head is design. You think they are too small?

No, its just that im about to fit larger lift cams to a neo head(already dummy fitted them) from an rb26

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No, its just that im about to fit larger lift cams to a neo head(already dummy fitted them) from an rb26

thats interesting. what lift are your cams? As a matter of fact mine are GTR cams aswell. NEO head has similar solid lifter design to rb26. Cams are fully bolted in and head assembled with no problems. Apparently any lift bigger then 9.3 ish exposes the oil something or rather. Anyone know what kind of power levels the poncam can or have supported?

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