[Mr Twister]

I think I like this for my combo, tell me what you think.


Cam Style:Mechanical roller tappet
Basic Operating RPM Range:2,600-6,600
Intake Duration at 050 inch Lift:236
Exhaust Duration at 050 inch Lift:244
Duration at 050 inch Lift:236 int./244 exh.
Advertised Intake Duration:286
Advertised Exhaust Duration:294
Advertised Duration:286 int./294 exh.
Intake Valve Lift with Factory Rocker Arm Ratio:0.525 in.
Exhaust Valve Lift with Factory Rocker Arm Ratio:0.543 in.
Valve Lift with Factory Rocker Arm Ratio:0.525 int./0.543 exh.
Lobe Separation (degrees):112
Intake Valve Lash:0.020 in.
Exhaust Valve Lash:0.020 in



Car is 3300 pounds , TH400, 10" converter, 3.73 gear
Engine is a 400 +_.060, 300 cfm E-heads, 10 to 1 cr
Fast 4150 style throttle body with a Torker II.

[Lee]

I think you will instantly regret not going MUCH more aggressive.

At what lift do your heads flow 300cfm? You need to get lobes that will get you up into that lift.

If you were going to drive it daily, in traffic, then that might be a good choice. But if you are looking to really gain performance, you need more duration. The .050" duration numbers on solids do NOT directly correlate to those of hydraulic cams, and that cam will be really tame.

I have a 251/259 @ .050", ~.630" lift solid roller in my Falcon wagon, and I had no trouble with driving it on the Power Tour. I originally had a 243/251 SR in it, and I thought it was too mild.

[Mr Twister]

I do drive it about 6,000 miles per summer on days the weather is good.

[Lee]

I put 4,400 miles on my car in 12 days, on the Power Tour :-)

Off hand, I'd suggest going about 7-10 degrees bigger, and increase the lift to make the best use of your heads.

[screamingchief]

I dunno,might be the chosen cam looks so tame because of the EFI unit he is using.

Fuel injection indeed changes how I look @ this cam choice,normally I'd totally agree that it's a pretty tiny SR cam,and that it needs to be way bigger like Lee is saying,but two things tend to temper my POV in this sorta situation,and those things are manual transmissions,and fuel injection,if/when either of those are in play,then yeah one needs to be somewhat conservative @ times when it comes to street driven cam selection.

Were it a carb,I'd say yeah run more duration & lobe lift as SOP.

But as the combo is now with the EFI,it could be a fairly decent choice.

My only ???? here would be to ask if there is a specific hp goal in mind with this deal?

JMO

Bret P.

[Mr Twister]

It needs to be able to idle at stop lights. It also needs to be run on pump gas. This is a street car so performance does not have to be like that of a race car. I have a plate style NOS kit installed in the car (Cheater Kit) for fun.

[Lee]

How much stall speed do you have?

I've designed dozens of LS cams (fuel injected) and tested them on the chassis dyno. I've actually found I can go with BIGGER cams with the fuel injected motors, as long as the guy doing the tuning knows what he is doing. A recent 5.3 motor has a 236 @ .050 HR, and put 420+hp to the wheels.

If you've got over 3000 stall, you should be fine with mid 240's on the intake.

[David Holmberg]

Listen to Lee, he's been there.

I ran a 254/262 solid roller in my 474 on the street, very streetable. Even enough vacuum for power brakes.

[dmac]

If this was a 455, I'd say go a little bigger, but I think in a 400, it will be great for the long drives.

[Mr Twister]

The converter is an old Coan that I have had for years and never used. Back when I bought it they called it a Pro-Street 10" and supposed to stall at 3000-3200.

[GTOLou]

Originally Posted by Lee

The .050" duration numbers on solids do NOT directly correlate to those of hydraulic cams

I don't want to steal this guys thread - BUT, WHY IS THAT?

I am putting together a 242/246 HR cam with solid roller lifters and feel like in a 462 that will be plenty big with ported eheads - and still have vacuum for power brakes.

His 236 intake duration is the same as the HR "Old faithful" that SD sells and that is a great mid-range cam.

WHY don't duration numbers for SR's and HR's translate??

[Steve C.]

WHY don't duration numbers for SR's and HR's translate??

In the OP's post brand and lobe info not known here but if you were to look at Comp Cams XE solid roller lobe 4873 as an example. It is rated 236 at .050" lift. With 0.016" lash and a 1.5 rocker ratio at 0.050" valve lift under running conditions on a Spintron machine that lobe will have about 241 degrees actual duration delivered 'at the valve'. In comparision Comp hydraulic roller lobe 3315 rated with 230 degrees at .050", six degrees less than the solid roller lobe, would be a similar 240 degrees duration 'at the valve' under running conditions. Exact duration numbers would depend on lifter preload, pushrod flex, etc.
But like a shock absorber, the hyd lifter 'gives' just a little as you load it under running conditions. Keep in mind those duration numbers are at .050" valve lift. Take a look at the entire lift curve from about .020" thru max lift and the solid roller lobe will have more area under the curve.

( If you want to upgrade the "Old Faithfull" 236 degree HR cam to a sold roller cam.... add on some more duration. IF a XE solid roller lobe were in use I would suggest at least minimum 242 degrees at .050" and it would have similar results with solid roller lifters in use. Hyd roller lobes with solid roller lifters wouldl be entire differant issue)



.

[Mr Twister]

This is a Crane grind.

[lust4speed]

Originally Posted by Steve C.

...It is rated 236 at .050" lift. With 0.016" lash and a 1.5 rocker ratio at 0.050" valve lift under running conditions on a Spintron machine that lobe will have about 241 degrees actual duration delivered 'at the valve'...

Why did we pick up 5° duration? At first I thought it might be heat from the running engine tightening up the lash, but I believe the suggested lash settings are for a warm engine.

[Steve C.]

"... at 0.050" valve lift under running conditions..."

That could be a little misleading, maybe actually I misspoke. Instead of 'valve' lift I meant 0.050" lift on the lobe, or at 0.050" tappet lift.

Valve lash effects the amount of duration. That same SR lobe with 0.012" lash has 243 degrees duration at the valve.

.

[screamingchief]

Originally Posted by Mr Twister

I've actually found I can go with BIGGER cams with the fuel injected motors, as long as the guy doing the tuning knows what he is doing

Annnddd as long as the hardware is there to support it as well,I agree.

But if his injectors lb/hr is maxed out @ 100% duty cycle struggling to support the additional HP a bigger cam is sure to make,then it's not very likely it's all gonna work as planned,and that's just one possible area where problems could arise.

I mean lets face it,we know almost nothing about the system & hardware he's using other than it's EFI due to him stating the use of the FAST throttle body.

So me,I'd wanna know a lot more specifics about the system & hardware before recommending he jump head first into a bigger cam.

That's why I asked if there was a solid/tangible hp goal for this build.

IMO,that's a key factor in any EFI build,a solid hp goal as you have to have a good idea what sorta lb/hr the engine is gonna want upfront in order to better select the proper combo of parts to make it all work as planned.

And the last bit of the quote in bold,that's always going to be the real catch 22,no?
Carb or EFI,good tuning is always key.

He never said who'd be tuning this,so again were in the dark on that deal,so IMO we gotta take that deal with a grain of salt here.

FWIW

Bret P.

[Mr Twister]

The supporting EFI parts are MEFI 4A by GM. These are very tuneable although are looked upon as old tech. I have seen these Mefi systems support high horsepower boats, in fact I know 1 over 1100 HP. Also a friend of mine who is a member here has one on a 600 hp 455 NA. motor. I will be tuning my engine on a dyno with help from someone experienced in doing it.

[HWYSTR455]

I agree that since this is a 400, and with that static CR, it's a good choice over going bigger, especially if down the road you plan on going to overdrive. The spray will fill the gap if you wanted/expected more power.

Only thing I would have liked to see is more lift since it's E-heads, but overall, still a good choice.

.

[Cliff R]

+2

Pretty small cam for a solid roller, and not overly aggressive. It's a bit small for the CID and head flow, but considering you posted in the Street section, should work quite well for a vehicle that will see 6000 miles of street use per year.

I'm not a big fan of HR camshafts for engines that make peak power past about 5800rpm's. Sure, they can be made to work, but if you don't mind periodical valve adjustments, the solid roller is going to be a much better choice all the way around, for what you are doing......IMHO......Cliff

[PONTIAC LARRY]

Yeap that will drive like a champ but leave alot of HP on the drawing board. Atleast run 1.65 or 1.7 rockers and squeeze more lift out of it since heads flow so well. I drove a few thousand miles on a small solid roller in my 400 GTO with no driveability problems and only had a 2500 stall and 2.93 gears. It was a bigger 242/252 @ 050 112 LSA and .556 lift on 1.5's.. Its a Untradyne grind that Bullet does , go tit from Merrick out of Colorado. My cam with 1.65 would be decent I think to your combo proposed. Also never had any lash coming loose issues either.