Have a small solid cam(specs in signature). Comp calls for 130 closed and 280 open(yet they also list a 120 closed and 300 open for the same came in red, supposedly if you are "racing" it alot).

The springs on the AFRs that just arrived are 120 closed and 285 open. Is this alright? Should I be more concerned about open or closed? Cause open is right on, closed a little off. Thanks for the help.

Nick

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81 Z-28 355 Home Ported World S/R Heads(1.94/1.5) XS268 solid cam (230/236@.050, .477/.488 Net Lift), 650@ DP, Tremec TKO 5-speed, 3.42s, Nitto Drag Radials. 13.4@102.9 w/ 1.95 60ft time.

I would be more concerned with seat pressure simply because the valves AFR uses are Big x Heavy. Valve bounce on the seat really beats things up at rpm. The good thing is most of the AFR heads come with springs that will take BOATLOADS of lift. I would throw a couple of shims / spring locators under the springs to get the seat pressure up to spec, and live with whatever you have at max lift.

What are the spring specs Comp wants for the cam (spring rate, installed height, seat pressure, psi at 1.2" or whatever they call as 'open'),,, and what are the specs of the springs AFR supplied? Then all we need is gross lift and lash and I bet we find you have room to tighten the springs up. The cam in the signature is pretty small and I bet your going to be PLENTY safe with shimming the springs up to seat pressure. Besides,, keep in mind the springs are going to loose some pressure with the first few heat cycles.

Nothing wrong with those pressures unless you plan on spinning your engine past 6500, then as long as the springs will take the lift it looks like a .060 shim will get you over the 300 mark with maybe 140 pounds of seat pressure. Naturally, the cam should already be broken in for those pressures to work.

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Custom Auto, your source for quality machine work, cores and new parts at competetive pricing right here in British Columbia 1-888-563-4050
A Canadian, EH? (with a 10 second street car)

I'm also going with 1.6 rockers so I'm gonna be hitting .519 on the exhaust(and the springs I got are good for only .550 lift). If I do a .030 shim I get 130 seat and just about 300 open and have enough room for the extra lift. Looks like my best option.

PS- With the head and rocker change, I won't have to change pushrod length correct?

[This message has been edited by AllGoNoShow (edited July 22, 2005).]

You may need to change pushrods, all you can do is check with your existing ones first. I would also suggest breaking in the cam with 1.5's to impart a little less pressure on the delicate lobes and lifters.

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Custom Auto, your source for quality machine work, cores and new parts at competetive pricing right here in British Columbia 1-888-563-4050
A Canadian, EH? (with a 10 second street car)

Cam is already broken in (has more than 1000 miles on it). I'm just changing heads, not cam.

Thanks for the help guys!

I love it when i get lucky!

The specs for the valve springs are listed on AFRs website as installed at 1.800 so thats what I figured they were installed at. Well after checking on a few springs with a digital caliper and bore gauges, turns out I got lucky and they are installed at 1.775.

Gives me 128 closed and 292 open. Only 4lbs off on closed and 12 on open...close enough I would think!

Should work flawlessly

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Custom Auto, your source for quality machine work, cores and new parts at competetive pricing right here in British Columbia 1-888-563-4050
A Canadian, EH? (with a 10 second street car)