Comp 987s with G5X cam?
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Comp 987s with G5X cam? My heads have Comp 987 duel springs (have 20,000miles) in them. I am looking into swaping out my TR224 for a G5X cam. Can I just do a cam swap or do I need to replace/upgrade my valve springs?
Re: Comp 987s with G5X cam? I don't think 987s will hold that much lift, I'm going to be running 977s, and I know some like the REVs. I originally was looking into swapping my TR230/224 for a G5X2, and was under the impression that the 987s would need to be replaced, but not sure.
Shawn
Shawn
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Re: Comp 987s with G5X cam? 987s are rated at 130 @ 1.800" and 325 @ 1.250"
977s are rated at 160 @ 1.850" and 440 @ 1.250"
that seems like a lot of spring pressure for hydraulic lifters (or no?)....
977s are rated at 160 @ 1.850" and 440 @ 1.250"
that seems like a lot of spring pressure for hydraulic lifters (or no?)....
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Brett Foote
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From: Bring it........ b*tch
Re: Comp 987s with G5X cam?
um, your G5X-2 cam has already broken two of your rev springs in only what, 2 months?...that's a pretty bold statement there.....
That's funny.I'm running Comp 987's set up by Jay at Absolute and he informed me that they should be fine with this cam, as I personally asked him about it. A quote from him:
"they are plenty of spring for that cam, some people look at a comp cam book and see that they are the recommended spring for old small block chevy cams that dont go much over .500 lift, the way i set up the 987's they have 20lbs. more on the seat and 40lbs. more open compared to 918's and they bind just before .700"
Sounds like they should be fine if set up properly to me. Although in this guy's case with that many miles on his 987's I would definately swap them out to new ones.
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Re: Comp 987s with G5X cam? so would I be ok just installing a NEW set of 987s?
Comp also makes a 985 which has the same closed pressure as the 977 but a little lighter than the 977 open. I'm trying to avoid swaping lifters if I don't need the high spring pressure.
987 set = 130lb @ 1.800" and 325lb @ 1.200"
985 set = 150lb @ 1.800" and 365lb @ 1.200"
977 set = 150lb @ 1.800" and 400lb @ 1.200"
Comp also makes a 985 which has the same closed pressure as the 977 but a little lighter than the 977 open. I'm trying to avoid swaping lifters if I don't need the high spring pressure.
987 set = 130lb @ 1.800" and 325lb @ 1.200"
985 set = 150lb @ 1.800" and 365lb @ 1.200"
977 set = 150lb @ 1.800" and 400lb @ 1.200"
Re: Comp 987s with G5X cam? Whats really funny is I talked to Jay 2 days ago and he said that 987s and big XER's dont mix. He said you run that big of a cam you need 977s.
Phillip
Phillip
Re: Comp 987s with G5X cam?
Whats really funny is I talked to Jay 2 days ago and he said that 987s and big XER's dont mix. He said you run that big of a cam you need 977s.
Phillip
Phillip
Re: Comp 987s with G5X cam? According to the Comp book, the 987s will be close to coil bind with a .600" lift cam when setup at 1.800". I'm not sure how Jay sets his springs up with 20 lbs. more on the seat. That would give you even less possible lift. Also, the only difference between a 985 and a 987 is that the 985 has a 973 inner spring with more pressure.
Re: Comp 987s with G5X cam? We ran into float with the 987s on AS S2.5 heads 2 weeks ago.
If you are set on a dual, REVs or 977s. The new crane dual does not have enough pressure to control the valve. It has less open and closed pressure than a 987 according to their website.
If you can live with a single, the Isky 295 Ds work well with no control issues. There are a few cars with that setup, but it is $100 more. The springs are run for a 1000+ simulated miles. If any from that set break, the entire batch is tossed.
Hope that helps
If you are set on a dual, REVs or 977s. The new crane dual does not have enough pressure to control the valve. It has less open and closed pressure than a 987 according to their website.
If you can live with a single, the Isky 295 Ds work well with no control issues. There are a few cars with that setup, but it is $100 more. The springs are run for a 1000+ simulated miles. If any from that set break, the entire batch is tossed.
Hope that helps
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Re: Comp 987s with G5X cam?
Whats really funny is I talked to Jay 2 days ago and he said that 987s and big XER's dont mix. He said you run that big of a cam you need 977s.
Phillip
Phillip
Are the Comp 977 springs the same diameter as the 987's? Could I just do a direct spring replacement or would I need new retainers and seats?
Launching!
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From: Sachse, TX
Re: Comp 987s with G5X cam? 987s not enough spring pressure?!? My springs haven't shown any signs of valve float on the dyno, but I've put 2k miles on them since then. I'd like to know the definite answer on this also.
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From: Bring it........ b*tch
Re: Comp 987s with G5X cam?
987s not enough spring pressure?!? My springs haven't shown any signs of valve float on the dyno, but I've put 2k miles on them since then. I'd like to know the definite answer on this also.
Re: Comp 987s with G5X cam? The 977's use the same retainer as the 987's, but you should install them at 1.850 height rather than the 1.800 height that the 918's and 987's are installed at.
Bret
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From: Bring it........ b*tch
Re: Comp 987s with G5X cam?
The 977's use the same retainer as the 987's, but you should install them at 1.850 height rather than the 1.800 height that the 918's and 987's are installed at.
Bret
Bret