Performance Pontiac Power Predictons??

Hey everyone, my 455 is going on the dyno tomorrow! Any TCO big brain gearheads wanna take an eduacated guess at the numbers it'll put up?? Here are some specs:

462ci (4.18 bore x 4.21stroke)
Cast #13 heads
72cc chamber
2.11 x 1.77 valves
ported by Jim Butler (no flow #'s)
Forged flat tops
12.5:1 compression
(9.8 Dynamic compression)
284in 292ex
241 249 @50
.580 .603 Lift
110 L/S 106 C/L
Hydraulic flat tappet
1050cfm E85 Quickfuel carb
Edelbrock Victor intake
Heddman coated 1 3/4primary - 3"collector

[MR.hp]

594hp and 632tq.

[smooth_358]

I honestly have no idea.. but its good to see at least one of us without a job still having fun building things

[old vette dog]

600 600

[jollywrencher]

Wow 600? I'd love to see it. Hey 602 did you use a desktop dyno to come up with that?

[MR.hp]

Wow 600? I'd love to see it. Hey 602 did you use a desktop dyno to come up with that?

Nope that was off the top of my head. I could be a little high as the cam duration is a little short, But then I have seen engines with BIG duration cams be dogs so I am going with what I think it might be.

Would be interesting to see what a 2-plane intake would do for tq. on that monster.

[black_7]

itl make 602hp

[Red Rocket]

575 HP

610 tq

Peak power at 6100-6200

Peak torque at 4100

[waterbug1999]

669/669

[MR.hp]

So now that were back whar did she do?

[jollywrencher]

It was a big downer! At first it wasn't pulling for shit and sensed something was up. Checked compression and I had one cylinder down at 180 and the others were in the range of 210-225. Pulled the valve cover to see #2 cylinder rockers moving very little when turning it over. Wenzel thought it could just be the lifters bleeding off to much, got a bad batch. Then this morning when we tore into it we found a bunch of lobes scrubbed down. Big chips were out of the lifters and you could see heat marks. I used the supplied Lunati lube on the lobes. And a comp cams break in additive. Seat pressure wasn't anything crazy.

[Z28SSMAN]

Ouch. That sucks. What are the chances of that happening though?

[Red Rocket]

Lance, food for thought- you've probably checked this stuff anyway-

Check for binding- pushrods, rockers ETC.

Check for spring stack- adequate clearance? Adequate valveguide to retainer clearance?

Check Piston to valve clearance- lifter pump up could have caused the valves to crash. Best to use a solid lifter or a modified hydraulic to simulate a "pumped up" worst scenario. I hate to tell ya this, but I personally would have used a solid grind for more RPM capability and reliability.

Also check lifter to block clearance, not that your lifters are tight in the bores.

Hopefully you can get it figured out and find the direct cause. Don't be afraid to call Lunati either.

Also- clean that sucker out good!! Lots of metal in there.

Good luck.

[jollywrencher]

Here are some pics of the destruction! 4 lobes were good, the rest was UGLY! Red Rocket, I did check everything you suggested before had and everything seemed good. I have to believe that it was how he primed it with the starter. Everywhere I read now states that that is a big no no! I'll bring something to prime it next time, not sure if a chevy one will work or not.

[Red Rocket]

Man that's ugly.

I'd agree with ya now that Tork informed me of how things were done. No break in lube could have prevented this under the circumstances.

Found your thread on YB last night too, and that Pontiac guy brought up some good points too about the valve springs and break in procedures for the Voodoo cams.

Better luck next time I hope.