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Lets build some Hemi Big vlave heads

ole4 said:
are you using the longer valves to compensate for the hemi's shorter installed height?
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Yes . Cam lift issue's have kept the Hemi head from 25+ hp for me . And Getting higher compression is always challenging too . Doomed piston w/valve relief's is the best way I found . Milling these castings does weaken them and can lead to gasket failure at the higher temps of gas (425*) Alky doesn't seem to B a problem (300-350*) When I do mill .050" I reinforce the last 2 fins with billet aluminum .
 
If your gonna mill any clone head, U should consider reinforcing the base . Around the spark plug is where 90% of TG1 clone heads fail . Its a lack of aluminum in the casting that causes them to warp . And after milling a TG1 , Things get worse .
 
When dealing with 25hp+ open clones U have to get creative . And a 5th head stud can work wonders when dealing with serious compression ratios
 
The problem with some clone castings , like the TG1 is there's not enough aluminum in critical areas where the head gasket sits . And milling makes this worse . The TG1 is a good flowing akra head but does not work well modified .
 
Everyone has their own opinion on what to do with the short side radius . Be careful here and remember that U R now supporting a larger seat/valve and spring pressure over that bridge . I've seen broken seats from overdoing this area .
 
Mine would be to take the radius clear up the bottom of the seat, but not cut too far into the port floor. How'd this particular head end up having the seat so close to the spark plug hole? The guy in China just eyeballs the location and hand drill's it? :)
 
rkcarguy said:
Mine would be to take the radius clear up the bottom of the seat, but not cut too far into the port floor. How'd this particular head end up having the seat so close to the spark plug hole? The guy in China just eyeballs the location and hand drill's it? :)
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LOL , It may not B a guy . .
 
my class is 290 carb we are working them out to .750 bore what head/cam would you suggest. track is just short of 1/8
 
Heavy said:
my class is 290 carb we are working them out to .750 bore what head/cam would you suggest. track is just short of 1/8
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We have so many great cam profiles these days from NRracing, Isky , Dyno and others . Dynos F275 , NRracing's 274-0207, or Isky Black Mamba ...A 29/25mm combo would B a good choice .
 
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