GM847 cam
01-04-2007, 04:33 AM
#2
Registered User
Join Date: Jun 2001
Location: Hinesville, GA
Posts: 1,192
At a minimum, comp 987 springs, 3/8 roller rocker arms NSA, stock hardened pushrods, seats, most likely shims, retainers, locks, and guideplates.
Better off spending the extra coin on the valvetrain and getting early style comp R lifters, 918 beehives, titanium retainers, 10 degree locks, spring seats, hardened 1 piece pushrods (probably 7.2"), 7/16 studs, pro magnum or equivalent roller rockers NSA, adjustable guideplates (some dont center the rocker tip well over the valve).
Keep in mind comp 987's or equal size springs require machining to place that big of a valve seat in the head. This will require valve removal, or in my case it did, and the shavings and everything wont make it feasible to install those in the car if the head isn't prepared for them, even if you have the tool. I'd say spend the extra coin, get a lighter more stable valvetrain, and as far as I know, if you aren't pulling the heads, the beehive setup will work better and not require seat machining.
Did I get everything right here guys?
Part numbers I dont know, you'll have to search for those. I know the newer comp R lifters have problems so you might consider a different brand. I lucked out and got some older ones. The GM847 is a good cam, but unless you already have it, you might get a better deal getting a setup from bret with a custom grind of similar size, especially if you have ported heads. I put a GM847 in a friends car and it ran great considering the thing hard pocket ported heads and stock intake and TB, but you might find it better and more cost effective to buy a whole setup with a cam designed for it, IMO.
Better off spending the extra coin on the valvetrain and getting early style comp R lifters, 918 beehives, titanium retainers, 10 degree locks, spring seats, hardened 1 piece pushrods (probably 7.2"), 7/16 studs, pro magnum or equivalent roller rockers NSA, adjustable guideplates (some dont center the rocker tip well over the valve).
Keep in mind comp 987's or equal size springs require machining to place that big of a valve seat in the head. This will require valve removal, or in my case it did, and the shavings and everything wont make it feasible to install those in the car if the head isn't prepared for them, even if you have the tool. I'd say spend the extra coin, get a lighter more stable valvetrain, and as far as I know, if you aren't pulling the heads, the beehive setup will work better and not require seat machining.
Did I get everything right here guys?
Part numbers I dont know, you'll have to search for those. I know the newer comp R lifters have problems so you might consider a different brand. I lucked out and got some older ones. The GM847 is a good cam, but unless you already have it, you might get a better deal getting a setup from bret with a custom grind of similar size, especially if you have ported heads. I put a GM847 in a friends car and it ran great considering the thing hard pocket ported heads and stock intake and TB, but you might find it better and more cost effective to buy a whole setup with a cam designed for it, IMO.
Last edited by dhirocz; 01-04-2007 at 04:42 AM.
01-04-2007, 08:46 AM
#3
Registered User
Join Date: Dec 2003
Location: Oklahoma where trees are made of wood.
Posts: 2,725
If you need extra spring height you can allways get some keepers with .050 extra height and shim it up from there.
On the stock heads if you get the right seat you can run the wider springs without machining.
I used the K-motion K-800s and a titanium retainer with 10 degree locks and .050 extra height through the locks. I was able to set the spring height at 1.85 which put my spring pressure where I wanted it. Had this set-up on for 4 years.
The rest of my set-up included Comp R early lifters, Trickflow1 peice chrome-moly pushrods, 3/8ths studs, AFR guideplates (on my AFR heads, on stock heads I used the GM guideplates), and Comp 1.6 magnum steel roller rockers.
When I was using the factory valve covers I had to trim them in a few places to clear the roller rockers, with my AFR heads I am using the Moroso cast alum valve covers and the clear the valvetrain fine, I just had to trim the alternator and remove a tad from the VC and repolish it.
On the stock heads if you get the right seat you can run the wider springs without machining.
I used the K-motion K-800s and a titanium retainer with 10 degree locks and .050 extra height through the locks. I was able to set the spring height at 1.85 which put my spring pressure where I wanted it. Had this set-up on for 4 years.
The rest of my set-up included Comp R early lifters, Trickflow1 peice chrome-moly pushrods, 3/8ths studs, AFR guideplates (on my AFR heads, on stock heads I used the GM guideplates), and Comp 1.6 magnum steel roller rockers.
When I was using the factory valve covers I had to trim them in a few places to clear the roller rockers, with my AFR heads I am using the Moroso cast alum valve covers and the clear the valvetrain fine, I just had to trim the alternator and remove a tad from the VC and repolish it.
01-05-2007, 08:52 PM
#4
Registered User
Join Date: May 2001
Location: Chalfont, Pa.
Posts: 1,305
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