comp977?rocker arms?
03-06-2005, 09:27 PM
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comp977?rocker arms? i just bought absolute speed stage 2.5s with 2.04 in 1.57 ex and comp 977
springs. afterwards i found out i had to have comp r lifters and shims
which i bought. so today i followed a link that shows how to convert ls1 to ls6
pcv system and on the page it had a link about grinding the factory rocker to clear springs over 1.430 dia to clear the retainer.so i checked the sped on my 977s and they are bigger than 1.430.but i talked to other members who said they did not grind the rockers on their 977 set-up.so if there is anyone who knows about this please let me know.i plan on buying some harlands in the next couple of weeks but i dont want a disaster in the meantime also will grinding these make them more weaker than they are?
springs. afterwards i found out i had to have comp r lifters and shims
which i bought. so today i followed a link that shows how to convert ls1 to ls6
pcv system and on the page it had a link about grinding the factory rocker to clear springs over 1.430 dia to clear the retainer.so i checked the sped on my 977s and they are bigger than 1.430.but i talked to other members who said they did not grind the rockers on their 977 set-up.so if there is anyone who knows about this please let me know.i plan on buying some harlands in the next couple of weeks but i dont want a disaster in the meantime also will grinding these make them more weaker than they are?
03-06-2005, 09:45 PM
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I've got 978's which have the same deminsions as the 977's. From what I understand Jay used REV valves and the stems were higher off the retainer so that should not be an issue. One thing you should check is install height, my intakes were set up on a 1.830 not a 1.850 and coil bind is 1.195. Figuring .060 for clearance, that limits me on cam size.
03-06-2005, 09:50 PM
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Originally Posted by bigdsz
I've got 978's which have the same deminsions as the 977's. From what I understand Jay used REV valves and the stems were higher off the retainer so that should not be an issue. One thing you should check is install height, my intakes were set up on a 1.830 not a 1.850 and coil bind is 1.195. Figuring .060 for clearance, that limits me on cam size.
03-07-2005, 06:46 AM
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No shims on any of the rockers. Jay frequently used longer stem valves, so that shorter push rods were required, in my case 7.350. He said some guys did shim up to use a 7.40 but I don't know how that affects geometry. Also another crazy thing, my exhaust valves are set up on a 1.870 install height .020 taller than spec. I don't know what the logic is, since the intakes are.020 shorter than spec. All I can tell you is to measure everything. If you want we can discuss the problem of valve drop @ TDC too.I'm going to be on the phone today the better part of the day trying to find a bigger cam to fit, without screwing something up.
03-07-2005, 12:42 PM
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Measure your valve lengths and make sure you know what you have.
I run comp 977's, y/t 1.7 non-adjustables, .100 longer than stock manley valves, mine are set at like 1.75 but we wanted a lot of spring pressure for my blower setup.
I run comp 977's, y/t 1.7 non-adjustables, .100 longer than stock manley valves, mine are set at like 1.75 but we wanted a lot of spring pressure for my blower setup.
03-07-2005, 02:09 PM
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Hey PSJ with 1.75 valve spring height and coil bind at 1.195 what lift and duration cam are you running? Even with notched pistons I don't see how you get around the coil bind issue.
03-07-2005, 02:39 PM
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Originally Posted by bigdsz
Hey PSJ with 1.75 valve spring height and coil bind at 1.195 what lift and duration cam are you running? Even with notched pistons I don't see how you get around the coil bind issue.
I had no clearance with the stock rockers on my AS heads with the same spring/valve setup you have. I ended up pulling those 977's off and going with crane duals, as I didn't feel comfortable grinding away at my rockers.
