[moontower69]

Any thoughts on which cam will make most usable power for a stock 1974 Pontiac 354? It's a stock bottom end with some 4X heads milled to be about 8:1. Going to replace the stock cam (254 or 555) and want a little more than what an 066 replacement can offer.

No monster for sure, but a solid daily driver in need of some pep. Combo is T350 w stock converter and peg leg 3.08 outback, rebuilt qjet, 2.5 duals, xpipe and dynamax STs.

summit 2800 cam = 204/214 @ .050 .421/.444 lift (adv. 278/288)
lunati 10510700 = 207/213 @ .050 .437/.455 lift (adv. 250/256)

Seems like the Lunati has MUCH faster ramps so it should have more grunt for low compression engines - right? My goal is a grunty driver. Really just wondering if the Lunati is a better choice given my crappy compression. Want most area under the curve, curious if anyone has ever compared these 2 cams in the real world.

[pastry_chef]

Originally Posted by moontower69

lunati 10510700 = 207/213 @ .050 .437/.455 lift (adv. 250/256)

Seems like the Lunati has MUCH faster ramps so it should have more grunt for low compression engines - right? My goal is a grunty driver. Really just wondering if the Lunati is a better choice given my crappy compression. Want most area under the curve, curious if anyone has ever compared these 2 cams in the real world.

The Lunati is an awesome choice for you, you will be happy!

[Cliff R]

"Seems like the Lunati has MUCH faster ramps so it should have more grunt for low compression engines - right?"

You'd have to know where they are checking the advertised numbers at? The 2800 may be showing more off seat timing simply because it's checked at .002" tappet lift vs .006" for the Lunati (for example).

I do know that the Summit 2800 camshaft is very "mild" in 350 engines with low compression, so don't expect it to sound much different than a stock factory cam in the same build.....Cliff

[steve25]

With those small Exh valves in the 4X heads I think the added lift of the Lunati Cam will serve you better.
Have your heads been rebuilt with new valve springs?

[gtofreek]

The Lunati for sure. I have even used the 213/219 Voodoo in a 326. It idled good and ran strong. It was 9.2:1 compression, but the 354 with 8:1 won't be a problem for either of those 2 Voodoo cams.Don't let the fast ramp thing fool you. It is much slower on the closing side.

[Steve C.]

"Don't let the fast ramp thing fool you. It is much slower on the closing side."

Relates to this, a hint from the designer of UltraDyne cams & Voodoo lobes........

"I do all my cam designs as unsymmetrical cam designs. Although I design my hydraulics just like I do my roller profiles, The information I will give applies just to my hydraulic flat profiles.
Using Harvey Crane's Hydraulic Intensity formula, ALL my .842" tappet designs have an Hydraulic Intensity of 53.88 degrees.
This is the duration at .050" subtracted from the duration at .004", where the SAE has decided that hydraulic durations begin and end.
This Hydraulic Intensity of 53.88 is considered to be very aggressive, yet the cams do not have that 'sewing-machine' sound to them.
The opening side of the cam has a 45.26 degree equivalent Hydraulic Intensity, and the closing side is 62.50 degrees Hydraulic Intensity. The SEATING velocity of the valve is only 37% as fast as the OPENING velocity. This seating velocity is only slightly faster than GM uses on all their engines. At UltraDyne, I have had many hydraulic, as well as solids, go over 100,000 miles on the street. I keep the edge of the tappet about .018" away from the point of contact between the cam and tappet.
That 'sewing-machine' sound is caused by the valves hitting the valve seats too fast. The original High Energy cams, which I designed, produced that sound. I was shutting the valve at .0007"/*, only .0002"/* faster than GM. After hearing about the noise, a little thought made me realise the .0002"/* was only 40% faster than GM.
You do not have to shut the valve faster to keep the charge from getting out.
You have to design the cam so the charge, or inertia ram, is still filling the cylinder when you shut the valve.
Every cam I design, hydraulic, hydraulic roller, solid, solid roller, is designed using the same theory I have used for the past 29 years, and they all make excellent bottom-end torque for their duration."
UDHarold

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[track73]

I used a 2800 with 1.65 stock rockers and it ran great in my 400 with headers and QJET.

[Dave M]

I've had a Summit 2800 in 3 different cars since 1989. Probably put about 60k miles on it. Great daily driver type engine. This summer, we used it in my 68 Firebird convertible and it ran a 14.68 in the quarter. Engine is a 72 400 with small valve heads and 8:1 cr. Stock logs a crappy 2" exhaust with sharp bends (was like that when I bought it). TH350 Trans and 3.31 gears.


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[Dave M]

We just put that 400 in my son's 89 Formula. Will post times in that car. Should be a little quicker. Oh engine has a Cliff Q-Jet.


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[Squidward]

I ran the 2800 in a 350 a couple years ago. It was fun, an awesome driver type of cam. Will work with stock valvetrain and converter. It ran my FB into the 14's before I felt the need for more. I currently run a Voodoo 10510702 in a 350, but that would need more loving beyond stock parts (valve springs, maybe some gearing/converter). But even that cam is surprisingly streetable in a 350: 15" idle vacuum, runs a/c and power brakes without issue.

I would run either of your cam choices. The 2800 might leave you wanting a tiny bit more later on, tho.

[moontower69]

Thanks for everyone's good advice. My 16 year old son and I installed and broke in the Lunati Voodoo 700 cam (207/213 @.050) on my 74 Lemans. Used fresh set of #47 Heads (checked in at 84cc by local machine shop) w/ new Crower 68404 springs on a previously rebuilt bottom end (3.90 bore/.030 over) w new 60 lb Melling oil pump. Compression is 8.6:1 with Felpro gasket w stock pistons about 15 in the hole.

It is night and day from prior peanut stick #537441 camshaft. Now it smokes tires off the line, pulls hard from idle to about 3600rpm w/ stock converter and the stock 3.08 open rear. Feels like car has about 75-100 more horsepower on my butt dyno. These cams are magic.

Question, my son wants to put in 1.65 Harland Sharp rockers "for a little more top end" - currently it's out of breath at about 4200 now....but pulls fine to 4500 to chirp tires into 2d gear.

Heads did NOT get elongated pushrod holes but I've heard that based on specs of camshaft being small, it should work? Means my lift will go up 10% from .437 and .455 (becomes .477 and .500 lift). What do you guys think?

[i82much]

if you have an old car that is running well, back away slowly and drink a beer. then go eff something else up instead of the car!!

[moontower69]

Thank you, you're totally right, stop fixing it until it's broken....I have a standard bore 1973 400 block I can build up w my son, probably smarter use of time for sure!

[b-man]

Originally Posted by i82much

if you have an old car that is running well, back away slowly and drink a beer. then go eff something else up instead of the car!!

My thoughts exactly.

A rocker arm swap would do next to nothing anyway.

That’s a small cam and it’s more than fine for the normal driving rpm range. A little more top end = cam swap for something with about 10 more degrees of duration. The factory 068 cam advanced 4 degrees or even the Summit 2801 wouldn’t have been a bad option for a young hot rodder’s 350 build.

The tiny air cleaner you’re using isn’t doing your top-end revs any favors. Replace it with a normal 14x3” drop base air cleaner. And what happened to the rebuilt Quadrajet you mentioned in your original post? That E-clone carb is not up to par with a Quadrajet. So there’s two things that are holding the car back. The Performer intake is a nice match for a 350.

That fuel filter and all that rubber fuel hose laying on a hot intake manifold is a fire waiting to happen, do something about that asap.

[steve25]

I bet that with a AFR meter that you along with some timing curve re-work could fine tune another 8 to. 10 hp out of it and then not have to worry about added lift from 1.65 rocker breaking of the tops of your stock pressed in rocker studs or pulling them out.
I have BTDT!

Also that too darn small air filter is shaving off some top end power without question!