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Need Help with matching camshaft and valve springs #1402475 03/14/13 05:11 PM 03/14/13 05:11 PM
Joined: Oct 2010 Posts: 96 Oregon B Badge OP member
Badge OP member B Joined: Oct 2010 Posts: 96 Oregon	I have a 360 small block. I am going to install a purple shaft camshaft P 4120233 AC hydraulic flat tappet .508/.508 @ 292/292. I have a new set of Manley dual valves springs. Seat 115 lbs @ 1.80, Open 310 lbs @ 1.25. Are they to much spring for this cam? Thanks.

Re: Need Help with matching camshaft and valve springs [Re: Badge] #1402476 03/14/13 05:14 PM 03/14/13 05:14 PM
Joined: Dec 2009 Posts: 20,640 in a cattle trailer down by th... G Guitar Jones Paddle faster! I hear banjo music!
Guitar Jones Paddle faster! I hear banjo music! G Joined: Dec 2009 Posts: 20,640 in a cattle trailer down by th...	Quote: I have a 360 small block. I am going to install a purple shaft camshaft P 4120233 AC hydraulic flat tappet .508/.508 @ 292/292. I have a new set of Manley dual valves springs. Seat 115 lbs @ 1.80, Open 310 lbs @ 1.25. Are they to much spring for this cam? Thanks. Are they really duals or a single spring with a damper? But no, I don't think that's too much spring. "Follow me the wise man said, but he walked behind" '92 D250 Club Cab CTD, 47RH conversion, pump tweaks, injectors, rear disc and hydroboost conversion. '74 W200 Crew Cab 360, NV4500, D44, D60 and NP205 divorced transfer case. Rear disc and hydroboost conversion. 2019 1500 Long Horn Crew Cab 4WD, 5.7 Hemi.

Re: Need Help with matching camshaft and valve springs [Re: Guitar Jones] #1402477 03/14/13 06:30 PM 03/14/13 06:30 PM
Joined: Jan 2003 Posts: 16,376 D dogdays I Live Here
dogdays I Live Here D Joined: Jan 2003 Posts: 16,376	Important question: What is your spring installed height? I'd be surprised if you had all of 1.80" on a stock smallblock head. I've measured between 1.6 and 1.625 on mine. So 1.625 - 0.060 for coil bind -0.508 lift equals 1.057 maximum spring solid or coil bound height. Anything more than that and you're breaking things. Another thing, your spring has a rate of 355 lb/in, the reduction of height puts the seat pressure at 177 lb. That's quite a bit. I'm not as experienced as many others, but IMHO going high-lift on an LA motor takes some careful juggling of spring parameters. R.

Re: Need Help with matching camshaft and valve springs [Re: dogdays] #1402478 03/14/13 07:34 PM 03/14/13 07:34 PM
Joined: Oct 2010 Posts: 96 Oregon B Badge OP member
Badge OP member B Joined: Oct 2010 Posts: 96 Oregon	Good point. I have not measured the existing springs for installed height.

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