Valve springs to replace Comp 977's?
11-20-2005, 04:49 PM
#1
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Valve springs to replace Comp 977's? I'm going to be getting some heads that have Comp 977 springs on them. I'm planning to run a futral F13-14ish cam so I don't think the springs will handle that. I know the 977's are wider and this is where I need help.
What's a good replacement spring that I can just swap in to replace the 977's?
I also want to use stock style (not comp R) lifters.
Will the patriot's work for this application?
The heads are Absolute Speed 5.3's with 2.04/1.57 valves in them. I don't know the valve stem length.
Thanks.
What's a good replacement spring that I can just swap in to replace the 977's?
I also want to use stock style (not comp R) lifters.
Will the patriot's work for this application?
The heads are Absolute Speed 5.3's with 2.04/1.57 valves in them. I don't know the valve stem length.
Thanks.
Last edited by My90Iroc; 11-20-2005 at 04:59 PM.
11-21-2005, 10:37 PM
#3
Comp 977's are a very stout spring. They should easily be able to handle the F13. Actually it would be a bit much on the F13. If you don't know how old the 977's are and you feel you should swap them, the patriots would ba a good choice. I would personally choose the PRC platinums at Texas speed.
Comp 977 sets up at 177 lb's at 1.800 and 420lb.s at 1.250. Coil bind is at 1.160.
Patriot golds are 135 lbs at 1.800 and 350 at 1.150. Not sure of the coil bind.
Obviouslly the 977's are a stiffer spring.
Comp 977 sets up at 177 lb's at 1.800 and 420lb.s at 1.250. Coil bind is at 1.160.
Patriot golds are 135 lbs at 1.800 and 350 at 1.150. Not sure of the coil bind.
Obviouslly the 977's are a stiffer spring.
Last edited by Beast96Z; 11-21-2005 at 10:49 PM.
11-21-2005, 11:35 PM
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I used some 977 springs a while ago set up a lil looser than 1.80 installed hieght and they worked great. Had to clearance the stock rockers just a bit though. Cam was a 232/236 with wround .600 lift. Spun cleanly to 6800 rpms with stock lifters.
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11-22-2005, 08:45 PM
#8
Originally Posted by GuitsBoy
I thought that the 977's had a coil bind of 1.195, entirely too tight for a near .600 lift cam. Even if coil bind is at 1.160, it dosnt even leave the recommended .050 clearance with an f-13.
11-22-2005, 10:01 PM
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you have to cut bigger spring pockets for the 977s anyways...so depending on how they are cut...you may be able to set them up at a 1.900 installed height. You can also get +.050 locks for very cheap.
977s can be set up at 1.900 installed height with 133lbs on the seat. Coil bind is 1.195 and gives and overall range or .705 lift. Take out the .050 you need before coil bind and thats .655 usable lift.
But I have no idea what your spring pockets are cut to depth wise, what shims you have, valve length etc. But they can work. The question is...is it more cost effective to just get new springs...or if you can maybe take out a shim or two, and get some +.050 locks, or if you have to get the spring pockets cut deeper to get your required install height to keep the 977s.
977s can be set up at 1.900 installed height with 133lbs on the seat. Coil bind is 1.195 and gives and overall range or .705 lift. Take out the .050 you need before coil bind and thats .655 usable lift.
But I have no idea what your spring pockets are cut to depth wise, what shims you have, valve length etc. But they can work. The question is...is it more cost effective to just get new springs...or if you can maybe take out a shim or two, and get some +.050 locks, or if you have to get the spring pockets cut deeper to get your required install height to keep the 977s.
11-23-2005, 10:38 AM
#10
Sorry to answer for you, My90Iroc but...
The heads in question already are cut for 977's. The thing is, he's not sure weather the seats are deeper or if the valves are longer than stock. I worry about cutting the seats deeper. I dont know if theyre all old wives tales, but i head scary stories of heads imploding at the spring seats where they were too thin. I guess at this point it dosnt matter much, as i believe My90Iroc placed an order for some gold duals. If the seats were cut deeper already or if the valves are +.100, can the new gold kit be shimmed that much?
Originally Posted by 383LQ4SS
you have to cut bigger spring pockets for the 977s anyways...so depending on how they are cut...you may be able to set them up at a 1.900 installed height. You can also get +.050 locks for very cheap.
977s can be set up at 1.900 installed height with 133lbs on the seat. Coil bind is 1.195 and gives and overall range or .705 lift. Take out the .050 you need before coil bind and thats .655 usable lift.
But I have no idea what your spring pockets are cut to depth wise, what shims you have, valve length etc. But they can work. The question is...is it more cost effective to just get new springs...or if you can maybe take out a shim or two, and get some +.050 locks, or if you have to get the spring pockets cut deeper to get your required install height to keep the 977s.
977s can be set up at 1.900 installed height with 133lbs on the seat. Coil bind is 1.195 and gives and overall range or .705 lift. Take out the .050 you need before coil bind and thats .655 usable lift.
But I have no idea what your spring pockets are cut to depth wise, what shims you have, valve length etc. But they can work. The question is...is it more cost effective to just get new springs...or if you can maybe take out a shim or two, and get some +.050 locks, or if you have to get the spring pockets cut deeper to get your required install height to keep the 977s.
11-23-2005, 11:24 AM
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He bought my AS 5.3 heads. I ran these with a 231/237 ~.600 cam and had no issues. The seats are cut for the 977s and they only have about 5K miles on them.
I think he wants to change springs for peace of mind. The PRC or Patriot springs will be fine.
I think he wants to change springs for peace of mind. The PRC or Patriot springs will be fine.
11-23-2005, 12:17 PM
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I dare say Comp 987's. Set up correctly, they're up to the task, and I think they're the same O.D. as 977's. TEA used to use the 987's on their 5.3L heads and used to stand behind their ability to hold up to .610 lift or something like that (as per the way used to install the 987's). They held up great on my old 231/237 setup- no valve float up to 6900rpms.
11-23-2005, 12:26 PM
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So you guys are all using these kind of spring pressures with stock lifter? I wouldn't think the stock lifter would be up to the task of 177on the seat and 420ish open but maybe i'm wrong.
11-23-2005, 12:53 PM
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i've got these heads w/ these springs (well, they used to have 977's). the valves in question are +.070" in length. now, that dosn't mean that the install height will be +.070". Jay hung the valves very low in the seats which is why he used the longer valve stem.
currently i'm running comp 921's (same diameter as PRC's or Patriots). i had to install an .050" shim to get the springs to the desired 1.800" install height.
you will definetly need to check install height on your springs and shim accordingly. there is no telling what your install height will be with this setup without measuring.
good luck!
currently i'm running comp 921's (same diameter as PRC's or Patriots). i had to install an .050" shim to get the springs to the desired 1.800" install height.
you will definetly need to check install height on your springs and shim accordingly. there is no telling what your install height will be with this setup without measuring.
good luck!
