+1mm valves on an let advantage or disadvantage

[mirpur]

is it worth the upgrade of +1mm valves on an let, what are the gains or disadvantages,

[coupe-sleeper]

no dissadvantages really but personally unless wanting above the 450bhp mark i would not bother as gains would only be about 3% even in a race spec head. these heads flow very well anyway

[Rs1]

Disadvantages are that it injured my wallet

Will the +1's be accompanied by cams? doubles? solids? Need the full picture.

[coupe-sleeper]

oh i know its not cheap my build has cost thosands but when im driving with a 420ish bhp monster ill be very happy :-)

[mirpur]

rs1 the head is ported polished, bronze guides cut down on the exhaust side,double valve springs, titanium caps, i dont know if the spring seats are uprated items or normal cant seem to find any pics of the double valve spring seats, will be running hydraulic new gm lifters with xe cams at the moment.
maybe solids and hotter cams later, i did ask to have a bit taken out of the head so if i do go for hotter cams the lobes dont touch but been told this cant be done until the cams are present as he doesnt know how much material to remove

The valves taken out were rec 458 wasted stem 33mm they have only done 400 miles and standard on the other side but i want to aim for around 500bhp

[mirpur]

Where would money be best spent on the +1mm valves or solid lifters with hot cams and run the standard sodium valves with rec 458 wasted stem on the inlet, head already ported and polished with double springs and titanium caps

[steveboyslim]

no dissadvantages really but personally unless wanting above the 450bhp mark i would not bother as gains would only be about 3% even in a race spec head. these heads flow very well anyway

Who ever told you they will account for a 3% increase is talking rubbish.
You cannot put a percentage gain on any indvidual modification, it is the sum total of the parts which give you the overall power figure.
Doing only part of the work will affect the power delivery for the worse.

Steve