Will the Crane Gold Race Rockers work with an '87 LB9? I'm just wanting to make sure. And what would be better, 1.5 or 1.6? Is 1.6 worth getting new springs?

 

Quicksilver,

I've got Crane 1.6:1 roller tips on my LB9. On the thoretical spreadsheet, the lift and slight duration change should be good for almost 12 HP since the OEM cam is so restrictive. Crane used to advertise a 16HP gain on the LB9 5-speed in their performance comparison charts. I haven't seen one of those in many years, however. Frankly, I couldn't really tell much of a difference with them, but I know I didn't lose anything except about $120 and a couple of hours.

Since the valve timing is slightly earlier (by about 1½°) you should be able to theoretically run a little more advanced ignition timing, and the engine should produce more power at the low RPM ranges. Again, these are all theoretical, but the science supports the notion. I run several degrees advance over the stock spec, but I also use slower-burning gasohol, have a ported plenum and runners, larger MAF, AFPR, and ported stock cast exhaust. I still can beat a kid on a Schwinn from a stop light, but I'm sure the 2.77 gears aren't helping.

The Gold Race rockers should fit if they are the self-aligning type, or if you are planning to install guide plates. They should also fit under the rocker covers, but you'll have to check the clearance around the PCV breather and oil filler baffles to be sure.

And forget about the need for new springs with the moderate increase in lift. The "LA" cam provided with the LB9 auto trans cars was so mild, there is no need. You would have to get nearly 1.9:1 rockers to even approach the .450" lift rate where you might even consider new springs. Even the manual trans LB9 with the slightly improved cam profile (LameAss II) would need to have 1.7:1 rockers to exceed the .450" point where springs become a question at higher RPMs.

Now if you're concerned about the springs preventing the valves from floating and allowing better upper RPM power, that's a different story. Factory springs with 85# of closed seat pressure just aren't that good at much above 4,500 RPM. Between the springs, extra mass of the heavy retainers, adn exhaust valve rotators, the weak springs are probably as much a reason for stock TPI engines falling off at those speeds as the design of the intake runners. If that's your concern, then by all means, change them. Don't forget screwed studs while you're there. You'll want those to handle the extra spring pressure.

 

I don't plan on keeping the stock cam. I'm planning on going with the medium SLP, the product number is something like 51006 or something like that, i know the last few numbers are 006. Would I need new valve springs then? Yeah, I'm looking at the self aligning type.

 

BUMP