[TAQuest]

I have a Pontiac 400 with standard block. L2262 pistons, 60599 round port Edelbrock aluminum heads.
Upgrading from 2157 Edelbrock cam to a Lunati Voodoo 703 cam.
What kind of problems could I run into with this swap.
Thanks for helpful advice.
Ready To Rumble!!!!!

[David Jones]

Should be a hot rod. The 204/214 cam that’s in it is woefully small.

[steve25]

Valve spring wise the E heads will have no problem with the lift of the 703 Cam with 1.5 factory ratio rockers, but you will need to play with factory Q-jet a bit in terms of that Cams idle vacuum.

[TAQuest]

Originally Posted by steve25

Valve spring wise the E heads will have no problem with the lift of the 703 Cam with 1.5 factory ratio rockers, but you will need to play with factory Q-jet a bit in terms of that Cams idle vacuum.

I have the Edelbrock 1411. 1.5 roller rockers. The heads are the 72cc.

[Steve C.]

"Valve spring wise the E heads will have no problem with the lift of the 703 Cam with 1.5 factory ratio rockers..."

How about the catalog stated 120 lbs spring pressure ? If that is in fact where they are at.
And the 0.181" away from coil bind ?
Your opinion on those.

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[Formulajones]

I'd probably be asking Paul what kind of pressure he likes to see on those voodoo cams, he's setup more of those and has more dyno time on them than anyone I know.

[Steve C.]

X2


Personally I would not trust what a cam salesman would dictate, nor any general spring pressures listed on the Lunati website.

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[TAQuest]

Right. Called Lunati tech. They said the cam would work with the heads however I have had problems with tech advice from companies over the phone.

[Formulajones]

That may get you in the ball park and be fine for what you're doing but I tend to want to listen to the guys that build and dyno these things for a living as to what works best. I know Paul taylors the spring pressures to what controls the valves the best based on his testing and experience, and it's not always what the cam manufacture recommends.

[TAQuest]

Originally Posted by Formulajones

That may get you in the ball park and be fine for what you're doing but I tend to want to listen to the guys that build and dyno these things for a living as to what works best. I know Paul taylors the spring pressures to what controls the valves the best based on his testing and experience, and it's not always what the cam manufacture recommends.

He probably even has experience with these heads. What's the best way to contact him?

[Formulajones]

Originally Posted by TAQuest

He probably even has experience with these heads. What's the best way to contact him?

Best way to contact him may be a PM through the site here. GTOfreek.

He runs a shop in Tucson and he's extremely busy so might take some time for a response.

[TAQuest]

Originally Posted by Formulajones

Best way to contact him may be a PM through the site here. GTOfreek.

He runs a shop in Tucson and he's extremely busy so might take some time for a response.

Thanks. PM sent.

[steve25]

So there out of the box spec state that the springs are good for .575" lift and granted they not the best springs in the world, also I have never kept track of how there pressure drops off after a given number of rev's to 6K , but they should live for 20'000 miles I would hope if your not smaking them with over .500" lift

[TAQuest]

The Edelbrock head experts are saying that they have no problem (not having problems) with the springs Edelbrock installs in their preassembled heads.

[Cliff R]

The only way to know for sure is to remove a spring and retainer and check them. Everything else is an assumption that things will work fine.

When I build engines here, even if the heads are supplied from the owner or we get heads from another source, I take a couple of springs off and check some things out. First you need to make sure there is adequate clearance between the top of the seals and the bottom of the retainers.

Check the springs at the installed height for seat pressure, then compress them to the intended lift and check open pressure. Continue to compress them until the "stack" solid, then back them up apprx .080". This tells you the maximum running room for the springs and it should be greater than the lift at the valve from the cam you are using.

I don't run a "butt-load" of spring pressure on my street engines as a general rule, but pay very close attention to geometry and the items mentioned above.

I'm sure Edelbrock set those heads up with enough spring pressure and room for a .500" lift flat hydraulic cam, but I'd still check everything to make sure.........Cliff

[steve25]

For those who may be curious I just dug out a near virgin set ( like 15'000 miles ) of 6X-4 heads and here's the spring spec.
Intake seat pressure = 115
Exh seat= 110
Intake coil bind=.490"
Exh coil bind= .520"

[TAQuest]

Originally Posted by steve25

For those who may be curious I just dug out a near virgin set ( like 15'000 miles ) of 6X-4 heads and here's the spring spec.
Intake seat pressure = 115
Exh seat= 110
Intake coil bind=.490"
Exh coil bind= .520"

I noticed on the question and answer section on the cam sales page that someone asked about using the cam with those heads. The answer from Lunati was they needed to change the springs and gave a part number.
These ram air heads are so different than original D ports though. I don't think much cross references.
I specifically asked the Lunati tech on the phone about it and he said there wouldn't be a problem.
I'm hearing enough positive reports to try them out.

[TCSGTO]

I ran a Crower solid flat cam that had near .550” lift with 1.65 rockers with the stock Edelbrock springs with no problem. I only shifted at 5500-5700 though.

Like others said they aren’t the best springs but they work ok for a broad range of mostly street applications. They are a single spring with a flat damper. At least the ones that came with my heads were.

If you want a decent upgrade the Lunati 73100 springs work well. They are the same OD and when installed at Edelbrock’s standard 1.8” height gave around 135# seat pressure on my heads.

[TAQuest]

Originally Posted by TCSGTO

I ran a Crower solid flat cam that had near .550” lift with 1.65 rockers with the stock Edelbrock springs with no problem. I only shifted at 5500-5700 though.

Like others said they aren’t the best springs but they work ok for a broad range of mostly street applications. They are a single spring with a flat damper. At least the ones that came with my heads were.

If you want a decent upgrade the Lunati 73100 springs work well. They are the same OD and when installed at Edelbrock’s standard 1.8” height gave around 135# seat pressure on my heads.

Great info, thanks.
These;
https://www.jegs.com/i/Lunati/638/73...RoCW0QQAvD_BwE

[TCSGTO]

Yep, those are the ones. I used the Edelbrock retainers and spring cups.