Hi Folks. This is my first post here. With all else considered. What is the biggest cam I can put in my stock 375hp 396 (Ball Park figure) without getting into flycutting the pistons. What I want is a real rough idle. I just want to have a little fun like the old days. I already have Hooker 2" -3 1/2" headers, 800dp holley, 4spd, 4:10 gears. Either way I plan on claying the pistons to be shure.
Thanks in advance.

Off the top of my head...Competition cams H292 is a nice cam.It's hydralic,it makes good power,and you shouldn't have any problems in a 396.It does like compression but anything that has "a real rough idle" is going to need higher compression.

My two cents...

you want a mean idle in that 396, get the factory style ZL-1 cam. i think even clevit makes a copy of it. 262/273 @ .050 with .560/.600 lift solid cam. some of the cams are on 114 or 116 lobe seperation.. very mean idle.

i had one in my 396 with 11.7 to 1 compression (using the factory 11.0 to 1 replacement trw 375 hp 396 pistos) and with 11.2 to 1 compression in another engine. i set valve lash at .018 on both sides. ran locked out timming with a victor jr and 850 double pumper.

be fore warned, soggy bottom end. but it was a screamer when you mashed the gas.

just to let you know. toss out the 2" headers, i have been running the 396 for about 15 years now and not once in all my engine combos the 2" headers have ever shown a gain, if fact i have seen as much as 1 sec lost in my 1/4 mile e.t. with as much as 8 mph. because of the headers with no other changes.

small tube headers are thats all needed for even the best running 396 motors like down in the low 11's and high tens.

Comp Cams # 305 H will work great with that motor set-up, thats what I used in my bbc nova, it requires a 3500 stall, idles radical, pulls hard!

Pretty much any of the popular cams mentioned, plus many other popular ones, will give you a rough idle if you get them on a 106 or 107 LSA....but as mentioned, be prepared to lose bottom end. The engine I had a few years ago had a really nasty idle, everyone was almost afraid of it!! Little did they know that the car could hardly get out of it's own way. It was a dog at lower RPMs. I"ll never do that again. You'll love it for a couple weeks, then you'll miss the lack of performance.

I have to ask, are you just plain and simple after a rad idle, or do you want it fast as well? A radical sounding idle does not always equate to good performance, and poor performance is what you get when the total package isnt right. I dont know the rest of your specs, but if you were after any one of the camshafts mentioned, Id want 10.5:1 comp or a shade more, a good intake manifold(performer rpm or victor junior), and headwork(assuming they are good heads to start with). Your drivetrain sounds capable of keeping up with a motor like this(but all bets are off if you start launching the 4 speed on slicks). The gearing and 4 speed will like a bigger cam, but the parts may show their age and give out launching on slicks. And of course youve got enough displacement to get somethin done as well, youve just got to get everything working with the cam.


The one thing that gets me is the 2 inch headers. Id consider them to be a little excessive on a 396 unless you are really doing big things with the engine. For the most part, a 1.75 inch header could probably keep up and retain a little low end for you. Thats your call I guess.

As far as a camshaft, Id like a solid cam myself. Check out the specs on a lunati 402A4 solid cam. In a 396 with about 10.5:1 comp it would sound pretty rough at idle. And it would scream well with the gearing youve got and good headwork(with the 112 lsa, it will hold on to a pretty high rpm as long as everything else will). Be advised that this cam probabl wont really turn on well til around to 3500rpm, so dont expect a hard pull right off idle.

And thats why the rest of the top end has to be good. Try to run it with lower compression, stock heads and a stock intake and by the time the cam would want to really turn on, the rest of the top end would be the limiting factor not allowing the cam to perform as it should. That would be true with any one of those camshafts mentioned, not just the solid that I added to the bill. You will give up a lot of low speed power for high speed power. If the rest of the motor cant make high rpm power and the cam obviously killed most of the low end.......than you arent leaving a lot of room for gain cause your limited on both ends of the power curve. This is a case where it may sound good, but it may not run good. Know what Im sayin.

And if all you want is a radical idle and thats all, then pretty much any cam mentioned would do it.

Put a mild 274 or so cam that is ground on 106/102 centers in it for "Cackle"!!

Like the Crane SB 274H06 jobber.

But for a BB.

And a solid always give's that "I'm ready to go" solid lifter "sewing machine" tick people think a good hy-po cam should have!

And as a last resort, install a pair of good old-fashioned W/D/T smooth perforated inner pipe GLASSPACKS and full, long, out the back tailpipes!!

Talk about old-school like in the old days!! Great, imho!!

pdq67

I'd use the Lunati bracket master 231/239 @.050 .549/.558 110 LSA

It will have a nice "rump,rump" idle and actually make some real power.
And,as everyone has mentioned,lose the big tube headers.

JMHO

Mine got alot of attention with the Comp 294S(248* @ .050",solid flat tappet) cam,nobody like to ride with me for very long though.I'm looking to change to the XS282(4?) cam maybe,similar #s but split duration,should help the n2o a little.

I'd use an ISKY Z-66 solid grind, 108 LSA, 228@.050 and .520 lift. Should be plenty of room , even with the tight 108 LSA. Cam will be lumpy and is, imho, perfectly sized for a 6500 rpm 396. I.E., you'll get the lumpy idle AND a proper powerband.

Does the L88 cam have much of a radical Idle? Because I know where I can get a used one for a decent price.

Unless you have alot of compression, gear and stall i wouldnt go with that ZL-1 cam. get somthing that will be effective and suites your combo, not just some monster that sounds bad, because nothing is less impressive than a car that sounds like a pro stocker but runs like crap.

Does the L88 cam have much of a radical Idle? Because I know where I can get a used one for a decent price.

the L88 was just a step below the ZL-1 cam its just as mean im sure. i have not run one of those cams. it was like around 264/269 @ .050 something like that. little less lift then the ZL-1 cam.

it just depends on what your after at what you are willing to give up. when i ran the ZL-1 cam in my 396 i had 11.7 to 1 comp. ran on 87 octane fuel. ran the timming locked out at 36 degrees, ran a tci 10" convertor and ran with 3.70 gears and 4.56 gears. i had that engine for 6 years on the street and would run 12.20's on street tires thru the exhaust and mid 11's opened up on slicks. over 115 mph. engine was soggy below 3000 rpms but it didnt sneeze or nothing you could feel the lack of power. but when you floored it, it went......

nowadays im building just as stout engines but more effecient, making way better torque down low and better overall power. they might not sound as mean. but they do have a very nice tone .

just remember the bigger you go over board on cam the better you should be at tuning your set up. it takes some skill to get really big cams to work "smoothly" for street driving.

L88 cam is a bit smoother than my UD 276/284, but similar. Last time I had the real cam in the L88 ( 1978), in a 67 Camaro, it would build slowly to around 5000, and THEN smoke those M50/15s but good. Wierd ride. Smoking the tires mid way through 1st gear!

I'd recommend a MUCH smaller duration cam on a very tight centerline. The tight centerline will give you thel umpiness, but in a useable powerband.

Try a Lunati 40207. Just stuck one in an L-72 that now has about 10to1 compression but otherwise is stock. It has a pretty nasty idle but runs so much better than the stock cam you can't believe it's the same motor. Super broad power band a really good street cam.

I just bought this car last march and it believes to be a stock L-78 original. 11:1 motor with a small lope at idle. I checked the compression and I get 180lbs.-190lbs. I'll know more when I pull it this winter for the cam and new gaskets and seals. I'll check into that 40207 Lunati cam also.

I put a comp 292 hyd flat tap cam in my friends 70 396 chevelle a few yrs back with,holley 750 dbl pump,edel trq intake,headers,stock 290 heads,9:6:1 comp pistons,stock stamped longslot rockers, 4spd/3;31's and it has a nasty souding idle but is very streetable when the combo is dialed in correctly.

The cam is single pat 244 dur@.05,.550 lift,110 L/S but i would opt for a few more deg exhaust dur if your not running a good free flowing exhaust system.

We can drive this car in stop/go traffic for 30-40 mins and then twist it up to 6500 through the gears and it does not mis a beat but again fine tuning/dialing in time was the key here.

This cam come on real strong (Almost explosive)from approx 3500-6500 but is not real soggy on the bottom end if enough initial timing is used,it acceptable in stop go traffic esp with a stick,not a problem.

The cam does have a nasty idle with approx 6-7 inc vacuum @ idle which in his case was just enough to barely get by without a vacuum canister for the power brakes but keep in mind the power brakes were marginal in slow traffic with no vac canister.

This cam will have a nasty idle in 396 but is driveable too giving the best of both worlds with hot sounding idle and driveability too and hot perf too.


My friend has since decided to return the car back to stock trim and has already restored the body with all NOS GM panels (OUCH $$$). We also re-installed the stock intake,q-jet,and a much milder cam so he would like to sell the edel trq intake (for lrg oval port),holley 750 dbl pump,and the cam & lifters for $250 ish as a known working unit that we removed 3-4 months ago.
I was surprisied at how strong the car ran with the stock intake,q-jet and milder cam (222/226 dur @ .05,.525/.525,112 L/S ) but still had the headers. This cam idles fairly smooth but sounds authoritative/luggy with 14 in vac @ idle. But it had more low end and it pulls real strong through 5500-5600 rpms runing approx 90+ as strong as the hotter cam/setup we just removed which really made my friend reall happy. Gas mileage went from 5.5mpg around town to 10.2 with the q-jet and new milder cam to boot. The cam & lifters only had approx 2500-3k miles on them and we marked each lifter for each cam lobe when the cam /lifters were removed and greased it all up to protect it. I am not generally proponant of used cams/lifters but i know this cam has low miles on it,can see that the cam lobes and lifter faces look fine,and know that the lifter to cam lobe integrity has been kept for reistall so this would be a great buy for someone. He may be interested in selling just the cam/lifters so if interested give me your email and i will get it to him so he can contact you directly.

Scott