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Discussion Starter #1
Getting ready to order my cam for my SBC build. It's a 350 with somewhere around a 9:1 - 9.5:1 compression ratio. Cast iron Vortec heads that will be modified for higher lift. Edelbrock Performer RPM Vortec intake, Holley 750 vacuum secondary, longtubes, free flowing short dump exhaust.

The car is about 3300 lbs with me in it, and it has a manual trans with 3.23s out rear. (I have no problem swapping gears to something steeper if needed.) The car is used a few times a week, mostly for fun, but also to get around. Not much heavy traffic where I live. It'll see the drag strip almost every weekend once race season starts, and I want to be able to drive it there and back, but I'd really love if the car went low 13s (or better). I do a lot of high rpm driving, and the stock cam falls flat on its face at about 4500rpm :(

I've used Lunati in the past and been very happy. Here are the two I've been considering:

Lunati Voodoo 60102
.468/.489 lift
219/227 duration @.050
112 LSA

Lunati Bracket Master II
.480/.480 lift
230/230 duration @ .050
109 LSA

Originally I was decided on the Voodoo, but after more research I really like the idea of the higher 2-6k operating range and big top end with the Bracket Master, but I'm worried I don't have enough compression for the 230 duration and tigher LSA, although I've seen in an article where Lunati recommends the Bracket Master for a 9:1 motor. Any input is apprecaited!:thumbup:
 

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It's a 350 with somewhere around a 9:1 - 9.5:1 compression ratio.
In my opinion, if you don't know the exact static compression ratio, then you have no business choosing a cam for the motor.


Cast iron Vortec heads that will be modified for higher lift. Edelbrock Performer RPM Vortec intake, Holley 750 vacuum secondary, longtubes, free flowing short dump exhaust.
Current thinking, running on pump gas, is max 9.5:1 for iron heads and 10.5:1 for aluminum heads. If you have access to other fuels of better quality, then the sky is the limit.

The car is about 3300 lbs with me in it, and it has a manual trans with 3.23s out rear. (I have no problem swapping gears to something steeper if needed.) The car is used a few times a week, mostly for fun, but also to get around. Not much heavy traffic where I live. It'll see the drag strip almost every weekend once race season starts, and I want to be able to drive it there and back, but I'd really love if the car went low 13s (or better). I do a lot of high rpm driving, and the stock cam falls flat on its face at about 4500rpm :(
I'd pull the heads and measure the actual static compression ratio by cc'ing the heads and pistons, measuring the piston deck height and figuring what head gasket to run. Until you do that, you will have no idea what cam to run, but I can tell you this, with 9.5:1, you don't want to use the 230 cam. It's gonna need at least 10.0:1 to 10.5:1 SCR and then you may have problems with detonation with iron heads on pump gas. Read through this tutorial to get an idea of matching cams with static compression ratios. All the facts and figures were taken from Crane Cams engineers.
http://www.crankshaftcoalition.com/wiki/Cam_and_compression_ratio_compatibility

Also, do yourself a favor, read through this tutorial and discover the perils of running a flat tappet camshaft in today's world.....
http://www.crankshaftcoalition.com/wiki/Camshaft_install_tips_and_tricks

.
 

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Wrench Turner
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I agree with Tech.You don't wanna throw a 230 cam in there.That VooDoo cam will be a good match,IF,you have the 9.5:1 you say.I see this setup knocking on the door of 400HP if setup correctly.You can squeeze a little more compression outta the Vortecs as long as you get your quench set rite.Flat tops or a D cup piston would be a big plus here as well.
 

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Discussion Starter #4
tech- Thanks for the link. Those numbers read conservative to me (just by comparing cam recommendations I've gotten from manufacturers). Maybe I've just been looking at too many numbers these past couple days!

Good to know that the 230 duration is too extreme for my 9.5:1 (if we're being optimistic). I'll most likely just run with the 10602.
 

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Discussion Starter #5
I agree with Tech.You don't wanna throw a 230 cam in there.That VooDoo cam will be a good match,IF,you have the 9.5:1 you say.I see this setup knocking on the door of 400HP if setup correctly.You can squeeze a little more compression outta the Vortecs as long as you get your quench set rite.Flat tops or a D cup piston would be a big plus here as well.
You think I'm really getting anywhere close to 400hp? I was thinking this thing might make 350 if I was lucky, but I'd love 400! :thumbup:

I'll definitely pull the heads and measure my piston to deck clearance to figure out what gaskets I need to run.
 

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Wrench Turner
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It's all in the details.With flat tops,a spot on tune,& good exhaust,you'll be close.With factory dish pistons, a little less.The LT4 Hot cam can bring a basically stock L31 to 380 HP or so easily.That VooDoo will give more power under the curve than the HOT cam.You have to get it rite tho.Get your compression where it needs to be.A spot on tune.Long tube headers with an H,or,X pipe properly placed.With some minor head work on the Vortecs,400 HP would be completely doable.
 

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More for Less Racer
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Since you are planning quite a bit of strip running, would you consider a solid flat tappet cam?? There are numerous pluses to using one.

They aren't like they were in the old days where you had to be adjusting the lash all the time, with todays valvetrain parts and materials you will only have to check the lash but 2,... maybe 3 times a year. Once in the spring, and once midsummer.

You'll be up 30+ HP and Torque over a hydro cam, be able to use a Direct Lube lifter(laser burned tiny oil feed hole in lifter face) for better durability than a hydraulic flat tappet(no face oiling hydro lifters are made).

This is one of those little details that can really help you ;)

Certainly you can find an hour or two twice a year to have a set of feeler gauges and a beer in your hand, checking out your valvetrain, ...right?!! :mwink:
 

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Wrench Turner
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We just recently did a basically stock rebuild on an L31 using a Comp XR264 which has less duration than the cam you're looking at & just a little more lift.Compression was,IIRC,9.7:1 with the KB-193 pistons & .042" quench.This is a roller cam engine tho.650 Holley,DUI ignition.The engine dyno'd at 375 HP/420 torque.
 

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I run a lunati 270/278 219/[email protected] 50 515/530 lift hydraulic roller cam with dart shp 180cc heads and have about 9:1 compression and my motor runs plenty strong to about 6 grand before she is done and has excellent street manners and run a 600 vacuum secondary holley on top.

If your wanting to do a lot of strip time then its best to get everything matched up as what would make it the best for what your wanting to do with it. Don't rush it and save as long as you have to in order to be happy with what you end up with.

I don't race so I don't build mine for that as I gear more for street performance. What ever you do don't get a cam for sound as a motor that sounds good but runs like a worn out old horse won't do you much good.

Weigh the pros and cons on your cam as that is one of the biggest areas young hotrodders like I once did went to big and regretted it only to tear it out and put in a shaft that makes sense. Bigger is not always better. Good luck on your build
 
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