max duration @.50 for street strip cam...
 

with or without a vacuum can. 406 79 t/a 3500 stall #12 heads. 3:73 rear. Also why is a dual pattern cam better than a split pattern cam.

The "street/strip" cam in my 467 has a whopping 0.272/0.275 duration. With the 3,500 converter, I'd consider it somewhat streetable. Sounds good.

It's actually overlap that is the critical number in determining streetability (vacuum). You can have large 0.050" duration numbers but with a wide lobe center you can actually have decent idle vacuum numbers. 18 - 19 deg (at 0.050") of overlap for a 455 will be around 10-11" of idle vacuum (assuming enough initial timing, tuning, etc.). For a 400 ci, you prob need to be around 13-14 deg of 0.050 overlap. These vac numbers will be on the edge for needing a vac can.

I'm running 7-7 1/2" vacuum @ 1150 rpm on the street and don't need a vac. can

What cam? -Jim

UD 288/296 (108 ls) solid / flat in a 440" deg in @ 102

Manual brakes = no vacuum can = no limit on street cam duration. :thumbup:

my preference is nothing bigger than a [email protected] for a street car. you should have decent manners with that one. anything bigger and the 'trade-offs' will begin...

I ran a 254/262 (@ .050) solid roller in my pump gas combo for a few years without issue. Power brakes and no vacuum problems.

I bet my 280/284 will be nice on the street too, but I might need that Vacuum can. ;)

The Crower 60243 is a very good choice for the 400 with #12 heads. It will be well suited to the 3500 stall speed converter.

Vacuum at idle will be around 12" at 900-1000rpm's. It is about as big a cam as I would recomend for the application, and will make at least 425hp and around 460tq with unported heads.

The specs are 228/235/112. We like to see the ICL right at 108-109 degrees....Cliff

My RAIV 400 ran well and the A/C also with a UD 288.296 231/239 108 LS cam. Power brakes were even fine with a 304/312 UD. A little lumpier. Having the higher stall helps that.

Hydroboost brakes = no vacuum can = no limit on street cam duration = still get to have power brakes = best of both worlds

power brakes on a hotrod?..wtf has the world come too?..manual brakes done correct require very little pedal force..and have less problems too..4 wheel drums even stop well if done correct..my bird used to stop just fine at 132 mph, with factory drums..learn the basics..then cam the hell out of the engine and go have fun..

we habitually run bigger than 230 degrees..more like the 290b6...and you know when ya mash the throtle something fun is gonna happen..

Yep...power brakes, tilt, cruise, power steering, and overdrive....this IS the street section....May be adding power windows soon too.....smoke 'em if you got 'em....

Thanks, for the replys just seeing if I could go higher then the crower 60210 I have in there now. Was looking at the comp 292h. Even though some say street pontiacs don't like single patteren cams, and run power brakes.

67 lemnas whats hydroboost brakes?

Skip what are the specs of the ud 304/312 cam @0.50 and lift?

The Comp Cams 236/242 @50 hydraulic roller is the biggest I would use on the street. I used it so I know. Anything bigger is too rough an idle. I know a guy who used this cam in a 455 and ran 11.70s in a 73 T/A with a/c!

This the Street section. No vacuum needed for manual brakes, true.... but Pontiac used vacuum to control a lot of other accessories such AC controls, vents/dampers, etc.

If your close to the edge of suitible vacuum with power brakes or trying to find the edge, you better check your insurance and driving style. I have a can and power brakes and still have issues in parking lots..... the pedal will sometimes be hard as a rock. Once the booster opens the valve, everything is fine. The max vacuum for me is 11 inches (with a can). Also the can is not going to make more vacuum. It's only going to store it for later use. Hope this helps your decision.

I would like to keep it hyd non roller, cause I don't have a budget for hyd roller.

No offense intended,but that comment just suppoorts TIN TIGR's POV if you ask me.

Power brakes when handicapped with a marginal vacuum supply is often inconsistent and unpredictable,thus somewhat unreliable.

Manual brakes are not,they pretty much react the same everytime,manual brakes are the epitomy of consistency,albeit with a slightly higher pedal effort.

Poorly functioning power brakes are far worse a situation to have than properly operating manual brakes.

Even the factory knew that.

My '72 firebird is a factory manual disc/drum brake car,and it only had a lowly 350 2bbl. in it.

Stops fine.

Takes very little vacuum to operate the vents and such,and most those systems have their own vacuum resevoir as well,other than an unexpeceted leak affecting their operation,the worst that usually happens with a low vacuum supply is a short delay in the vacuum motor activation.

Vacuum advance,just get the right vacuum can.

Trans modulator,get the right adjustable unit and dial that in.

PCV,find an application that had a low vacuum supply as per OE,and use that valve as it would be calibrated to work with lower vacuum.

Almost every item that uses vacuum has some sort of solution/calibration for a low vacuum supply.

The factory has done such for years,so the answers are out there.

Vacuum is often the very last thing I consider in my cam selection process,that is if I consider it at all.

It means next to nothing to me,it ends up where it ends up,I just make sure to tune the combo for it,and move on to the next item on my list.

:-ohwell:

Max duration @ .050" for a Street/Strip cam???

The sky is the limit...

I base my cam choices on more relavent influences like intended application,desired performance target,and useable RPM range,static compression ratio,intake and exhaust tract components,head flow,converter,rear gears,that sorta stuff.

And I never look at just the .050" numbers,IMHO that's a huge mistake when choosing cams.

:2cents:

IMO your combo is screaming for a healthy flat tappet solid cam,crower #60310 comes to mind right off the bat as a sound choice.

Might even be able to pull off the Crower #60311 solid to be honest,you got the CR,convertor,and gear for it.

A solid any bigger @ .050" than those and you would have to tighten up the LSA,and that change would kill off the vacuum others are so concerned with.

But I digress for now,let the debates continue.

Bret P.

I agree with Bret about the solid flat.
The U/D 280/288, 247/255 @ .050 on a 110 LSA is a great street/strip cam in your area.
I ran 12.11 @ 112 3700 lbs at 5800' DA, 6x ported heads, rpm intake, dougs headers, 3.89 gear, 28" tire.
1.65 rockers, stud girdle.
Beauty, eh?

I agree Bret. I wish mine came with manual brakes since that would solve my vacuum issues. Also it's easier to stop a "lowly 350 2bbl" than a 455 4bbl. My LSA is 110 and 248 intake at 050. (if I remember right) I didn't think I would have an issue.

I didn't mean to get side tracked. Back on topic..... I've heard it said that 240 is the max for power brakes. I think more things are involved like someone said LSA, cu. inches, etc.

Now you have worried.
I was gon'a try some'tn close to yours.
Mine went 12.10 @ 112.74 last year with a 461/ RAIV top end with 2 collasped lifters.
3565 lbs/th400/3.42/27.5 tires.

More than likely I was 4000' higher in DA than you would be?
Many have seen mid to upper 11's with similar set up.

A Hydroboost system uses hydraulics instead of engine vacuum for power assisted braking.....the hydraulics are generated from the power steering pump.

I run a vacum pump on the inside of the driver side fender. It is bolted to the inner fender. This works great.
My street car runs a 248-256 solid cam. It has great street manners with 355 gears and 2800 stall. All this in a #3995 70 lemans runs well into the 11's driven 200 miles each way to the track. It all depends on the WHOLE combination of parts not just the cam and heads.

Well,that's what the car had in it when I got it,it now has a 455 with ported #96's.

Still needs a few things done to get it back on the road,just keep finding new problems as I solve the old ones.

Too many projects,,,too little cash...

Plenty of time though.

Still expect it will stop fine,even with the 455 in it.

All my other manual brake cars stopped fine,some with disc brakes,some with drums.

Agree that if I just had to have power brakes,I'd opt for the hydro-boost option,and not look back,it's well proven & trusted technology,as it was used on numerous OE applications already.

I personally dislike vacuum assisted power brakes,always have,always will,JMO/FWIW.

:2cents:

BP.

My UD 288/296 solid / flat w/108 lsa and the low 7.5" vacuum is a testament to that. Although my vacuum operated brakes have more positive action ( ever since going to a smaller dia. booster) every once in a while (about 5% of the time) the vacuum in the booster seems to go south and I loose the vac. assist. I've had cams w/ 8" @ idle and never a vac. brake issue. I imagine that cam in a 400 would carry a vacuum lower then 7" and idle @ 1200rpm +. Not good w/o a can. Larry

FWIW The old technology 292H is a decent cam but you would like the price and performance better running the Isky 292 Mega cam IMHO. The Isky is ground on a 108 LSA and will work great plus Summit sells it for much less than the Comp stuff. See what you think! JD

the hydraulic 304/312 I believe was 247/255 @ 0.050 I had it on a 112LS.

I will say I tried a solid flat tappet 288/292 UD. Pulled to 7000 BUT when I swapped on a single plane the brakes weren't always there. Were OK with the dual plane HO intake

Another vote for hydroboost. Run the cam you want. -Jim

Now i'm think'n i need more cam.

I had that problem w/ my UD only since swapping my rpm to a T11. The hood scoop on my 76 T/A likes the lower single plane but my booster likes the RPM. Gonna switch back! Larry