has anyone flowtested a stock 5mge head with stock valves and then flow tested a ported 5mge head with oversized valves? im curious to see the numbers. i have the ported head that came with my hks cams and weber intake etc.. and a set of oversized valves, but havent gotten the head machined for the valves and wouldnt have the money to have 2 heads flowed to compare them. still need to send the hks cams out to be spec'd and repaired as well.
From what ive learned from talking to engine builders is that 1mm over sized valves do not really flow more they are that way to make sure u can get a proper valve seat if the seat is damaged. If you wanted more flow you would need bigger then 1mm. the amount of flow difference would be so small for the for the cost of valves and money for work to get them put in. this is coming from people that use a flow bench. better off spending money on cams. and if its forced induction turn up the boost ull get more air in there.
the oversized valves for the 5m made by engbuilser on ebay(the ones i have) are larger then 1mm difference. the 7mgte valves are 1mm difference. but the 5m are larger. also, the valves are back cut which also increases flow. either way i have them and will use them. maybe ill get lucky and find a machine shop that will flow both setups for cheap when im able to get the machine work done. in the mean time. if they are somewhere easy to get to, ill try to measure them with my dial caliper. then ill look up the stock valve size specs in the tsrm to compare to.
ahhh i was thinking they were just 1mm. have 7m now so only have the .5 and 1mm bigger that ive seen. for the money and what i was told i would get out of it was not worth it. atleast with the 5m you only have 12 valves. i thought i read on here a long long time ago about some one modding up some chevy valves to make them work and they were quite a bit bigger. needed to shorted the shaft lenght or something and put a new grove for snap ring. I could be wrong though might have been my buddies 240z that had chevy valves put in it.