LT1-LT4 Modifications 1993-97 Gen II Small Block V8

Cam question

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Old 11-10-2008, 07:50 PM
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Default Cam question

Right now i have a 230/236 510/520 112lsa XE cam in my 383 below. I feel like this is kinda a baby cam for this stroker, and i want to throw a bigger one in there this winter. Question is, since the valvetrain is already set up for this cam, i should be all set to throw a bigger one in there right? This is what i've got:
CC 1.6 NSA RR's 7/16" stud
CC 1.430" diameter double springs (#987)
CC 10 degree titanium retainers and locks
CC Chromoly 7.200" pushrods

So i should be set to just throw another cam in there right? Any cam suggestions? I will also be doing 42# injectors, 58mm tb and a new tune from PCMfor less. Then in the spring, a dyno tune.
Old 11-10-2008, 10:51 PM
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Ha....I'm in the exact same boat, with same exact build. I think you would be fine just double check the valve spring ratings to your potential cam specs. I need to do the same on mine on my springs which I don't the brand ext. If anyone knows how to check them on the motor without the removal of the heads feel free to chim in. don't mean to hijack your thread

i haven't picked the exact cam yet but I plan on goin with something around 242/246 .59 110 LSA or so with a 3500 stall
Old 11-11-2008, 07:18 PM
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the cam feels "baby"? How? Ran it yet?
Old 11-11-2008, 07:40 PM
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Originally Posted by MTBSully
Right now i have a 230/236 510/520 112lsa XE cam in my 383 below. I feel like this is kinda a baby cam for this stroker, and i want to throw a bigger one in there this winter. Question is, since the valvetrain is already set up for this cam, i should be all set to throw a bigger one in there right? This is what i've got:
CC 1.6 NSA RR's 7/16" stud
CC 1.430" diameter double springs (#987)
CC 10 degree titanium retainers and locks
CC Chromoly 7.200" pushrods

So i should be set to just throw another cam in there right? Any cam suggestions? I will also be doing 42# injectors, 58mm tb and a new tune from PCMfor less. Then in the spring, a dyno tune.
That cam spec is with 1.5 rockers? Ill be running a hotter cam in my 350 and should be pretty streetable. Make sure your springs are gonna take the extra cam. Why not have LE grind you a custom cam for your application???
Old 11-11-2008, 08:19 PM
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The next camshaft that you may put in there may not have the same base circle size which would throw the pushrod geometry off so at the very least you will have to measure the correct pushrod length to make sure the geometry is still on.
Old 11-11-2008, 09:10 PM
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Originally Posted by AChotrod
That cam spec is with 1.5 rockers? Ill be running a hotter cam in my 350 and should be pretty streetable. Make sure your springs are gonna take the extra cam. Why not have LE grind you a custom cam for your application???
no im pretty sure those cam specs are with 1.6rrs
Old 11-11-2008, 09:37 PM
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well mine is a 230/236 565/568 108 and should be hot for a 350 but not crazy. I think yours would seem like a DD with a 383
Old 11-11-2008, 09:55 PM
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all i know is a 510/520 lift cam is NOT big enough to get enough air through those heads. I was looking at a 575/575 or so cam instead.

how is that 108lsa with surge and driveability? are you an a4 or m6?
also how do i tell if my pushrods are the right length?
Old 11-11-2008, 10:02 PM
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Originally Posted by MTBSully
all i know is a 510/520 lift cam is NOT big enough to get enough air through those heads. I was looking at a 575/575 or so cam instead.

how is that 108lsa with surge and driveability? are you an a4 or m6?
also how do i tell if my pushrods are the right length?
You can put one of your pushrods in there and set up the rocker with the proper preload etc just like you would if it were all going together. Then you turn the crank a few revolutions and take off the rocker to see the contact path that the rocker made on the valve tip. If its skinny and through the center of the valve tip then you have the correct length. If not, you need either a shorter or longer pushrod depending on if the mark is too high or too low.

I have a 107lsa cam with my A4 and it drives beautifully.
Old 11-11-2008, 10:05 PM
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It going in next week! But I have a M6
I have a great email I can forward you about push rod length from Lloyd Elliott
Old 11-11-2008, 10:18 PM
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Originally Posted by AChotrod
It going in next week! But I have a M6
I have a great email I can forward you about push rod length from Lloyd Elliott
please do:
chrisgeo@comcast.net
Old 11-11-2008, 10:20 PM
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Originally Posted by AChotrod
It going in next week! But I have a M6
I have a great email I can forward you about push rod length from Lloyd Elliott
Good call. It will basically tell you exactly what I just did except with pictures which will make it very easy to understand.
Old 11-11-2008, 10:32 PM
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Nice valvetrain. Investing in titanium retainers and locks is an important insurance for an aggressive cam with a hard ramp rate.

I agree you need a cam with higher lift than your current cam.

Call up Mr. LE, he will hook u up.
Old 11-11-2008, 10:47 PM
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Sent and yes its exacty what Steath said but with pics
Old 11-12-2008, 08:19 AM
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limiting factor on cam will be the springs you currently have.

If you upgrade to some Patriot Gold Extreme springs, you can pretty much use what ever hyd roller cam you want with out worries.

The cam that you have will definitely feel pretty small in a 383.

Lloyd
Old 11-12-2008, 11:25 AM
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ive looked online and can't seem to find the info i need. anyone know what lift the 987 valvsprings are good up to? I seem to remember its .600 but i want to be sure
Old 11-12-2008, 11:34 AM
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Originally Posted by MTBSully
no im pretty sure those cam specs are with 1.6rrs
No they are .544/.555 with 1.6rrs
Old 11-12-2008, 12:59 PM
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A good hyd roller needs 145 lbs of seat pressure and up to 155 lbs if you have steel retainers and want to spin 6500 RPM with out valve trane problems.

Even set up at 1.750, the 987 has 138 lbs of seat pressure and coil binds at 1.150 so it coil binds at .600 lift and you want .030-.040 or so before coil bind to be safe. This keeps you at a .570 limit for being "safe".

FWIW, the 987 is also rated as a .500 lift spring in the Comp catalog. .520+ lift, you can get a better spring in the same price range like the Crane 99893, K Motion K-800 springs, etc that will handle more lift and have more seat/open pressure.

If you have the 987's and do not know the set up ht or if they are set up at a taller installed ht (1.800, 1.850, etc) you have less pressure and are VERY limited on cam selection.

Lloyd
Old 11-12-2008, 01:07 PM
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MTBsully Just call Lloyd. He'll set you up right!!! He can set you up with springs and grind you a custom cam for you application!
I thought that cam looked tiny for 1.6 rockers. 544/555 is alittle better but still small for your car.
Old 11-12-2008, 01:23 PM
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Originally Posted by AChotrod
It going in next week! But I have a M6
I have a great email I can forward you about push rod length from Lloyd Elliott
Could I get that e-mail?

camimports@msn.com


Thanks,

Mark


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