Cam Choice. Any suggestions?
 

I’m looking to change out my cam in my 72 lemans convertible. The car runs great, run’s in the 13’s already. Below are my current engine and drivetrain specs.

400 +0.030
TRW pistions
Stock Rods with arp bolts
Stock crank with studs for the mains
72CC E-heads ported and polished. Overkill I know.
Edelbrock RPM instake
Holley 750DP carb
Crane roller rockers 1.65
Crane 272H cam currently in car
Heddman Hustler headers with 2.5”, flowmaster mufflers
CR is 10.2. Runs fine 93 octane pump gasoline
TH400 with shift kit.
3:23 10 bolt safe-t-track rearend


Any suggestions for a cam upgrade to provide some additional power?

Thanks!

I had that cam in my 400ci Turbo400/3.55 geared GTO. It ran a best of 13.6 on some 225/70-14 T/A's. Nice cam.
I swapped to a 220/224 .513/.528 lift hyd roller and have run a 13.5 even with a dry float bowl half way through second gear. The engines flexibility is now amazing. I'm working on upgrading my fuel system and hope to get to the low 13's or....... and still have a good idle with 15" vacuum.

I was thinking something like the Summit 2802 cam, maybe? Or a RAM IV style cam?

If ya got the money, I`d go with a hydraulic roller. You need to utilize those heads and a 2802 won`t. Not that a flat tappet won`t, but a roller would be more powerfull and prolly idle smoother with more vacumn.

Been here and done that, "041/RA4 cam in a low compression 400", bad choice horrible low rpm power/weak take off. As Cliff and others attest, to properly run a RA4 cam in a 400 it should have 11.0-1 compression, 3500+ converter, and rev the engine 6300-6400+. My car ran 13.60's @101 with the cam. I switched to a much smaller Crower cam and went 12.90's.

I really like the suggestions to running the hyd roller if you can justify the price. I'm not sure how to take advantgage of the improved head flow unless your willing to run a little more converter. You don't mention what converter, so I assumed stock, which limits the cam choices considerably. Looking at the weight of the car and mild 3.23 gear I suggest being carefull selecting cams above @0.050 .218-.220 MAX on the intake side with a stock converter. If your open to running a 2000-2500 converter then I'd go as far as .221-.225 MAX. Finding a cam netting a valve lift above .500 will help use the headflow too.

Take a look at the new Lunati "VooDoo" cams, there are some good looking numbers that might work well in your combo. JD

So much to be gained with a Hyd roller...I agree with David.

Hydraulic rollers are more expensive and less effective than solid rollers. With modern roller technology, no reason NOT to run a solid... Our customers LOVE them, and we've had zero complaints about them. Comp XE designs are excellent for a street application.

If you want to stay with a flat tappet, we've been selling a large number of the Comp flat "solids" with XE lobes. Not in catelogs, but great cams for street engines. About 1/2 the money of a solid roller.

Jim

What kind of specs would you suggest on a solid roller for Nick?

More effective than a hyd roller? How so? Don't they require periodic adjustment?

Agree on the solid roller, hyd rollers are dangerous over 6000 rpm. As for adjustments, pretty much once they've taken a 'set', it's not often you need to adjust them. Maybe check them like every 20k miles or so, that's about it, depending on use.

If your stuck on flat/hyd profiles, look at the 288H Crane. Can't go too much bigger because of weight and rear gear....

6000rpm? Stock rods? How'd we get to 6000rpm. The cam he has now runs out of steam at 4800.

FWIW This engine is not a 455, yes it can safely turn 6000 rpm's. According to the old HO builders guide, a 400 built like this:
"400 +0.030
TRW pistions
Stock Rods with arp bolts
Stock crank with studs for the mains"

Can "safely" turn up to 6300 rpm's as long as it's balanced. Don't fall for all the horror stories about the factory rods not being strong. In a 400 engine with a super good rod/stroke ratio it's a completely different ball game. JD

I've run 400s with that bottom end into the 7k range without issues, and I'd get 100k+ miles out of them. I wasn't suggesting that it would be turning over 6k, just stated hyd roller lifters aren't durable over that.

Lots of good suggestions. I was thinking of a hydraulic roller also, something like a CC XR276HR. But because of cost would like to go with a hydraulic cam such as the CC Magnum 280.

FWIW the car pulls way past 4800rpm with my current cam. I shift at 5500rpm and have seen 6k a few times with no issues. My best ET on street tires has been 13.6@102 and with DR 13.3@104. I do have access to a higher stall converter in the 2500rpm range and was thinking of swapping that in place of the stock converter also.

What are the spring pressures for the solid roller street cams?

usually 150-175 and 440 or more open, why would you use a single pattern cam on this 400, i'd go mechanical flat tappet if no $ for roller, XS274S comp 236-242 duration would be a nice street strip cam, maybe even a tiny bit small for a sollid but would work great with that combo, if nastier is required then the XS282S is another good choice 244-252 at .050 but would need a 3000 stahl

Honestly, I have not seen a Pontiac 400 run the old school 280H cam and break out of the 14's. I started out with the Speed Pro version of that cam .480..480 @0.050 .231/.231 adv duration 288/288 lsa 110. It sounded good but didn't run very strong on the topend. It spun out ok with the 2300 L88 converter I had.

Do you have 1.5 or 1.65 rocker arms? I know a proven combo, that will give the performance of the 276HR, for your 400 in a hydraulic. It's the 1.65's that makes it come to life. If you already have the 1.5's you need a different cam. JD

I've run a 400/RAIV cam combo in a 3858# car with a 3.55 gear and 2500 rpm stall converter and got to 12.70 in the 1/4. Needed more gear/converter as I was going across the line at 4900 rpm. Would shift to 2nd gear at 6000 rpm and 3rd at 5700. Stock rods/ARP bolts, Performer intake and Holley 750, stock pump.

I have 1.65 Crane gold roller rockers in the engine, so I'm good to go there.

Sent you a PM. JD