496 bbc needs a lunati but how is to big?

i am having trouble deciding on cam for my 496 its got a scat rotating assembly,kb pistons comp.9.8-10.1? dart pro1 325cc heads and so far thats where i'm at, the builder picked out a lunati 60240 cam witch is a solid flat tappet dura.@ .050 233in/241ex lift .570/.590 lobe sep.110/106 i will still drive my 3600# A-body whenever i want to but also getting into friday night drags.anybody who knows what this cam is like on the street or strip let me know could i go a little bigger for more power? the builder told me the motor would make 500hp on his dyno, i had hope for around 600hp and alot of tq.i have 5 kids so dont plan on to many changes to the motor once its built. still need to get power to the ground. any help would be grateful THANK YOU!

 

Do yourself a favor and call Lunati, tell them what RPM you want to run and they will tell you whether that is the right cam. Tech service is part of the price you pay for their product.

That is a tiny cam in a 496, the 325cc heads are big for such a low RPM operating range. you could really make some horsepower with the right setup.

I run a 496 (actually its a 505) with a Bullet solid roller 262/271 with .685/.663 lift 111 lsa on 110 ICL and I have a brodix 270 cc runner.

 

thank you glen for your info! is your motor street friendly?

 

I agree with Glen. Give them all the info and they will hook you up.Don't listen to buddys that think they know cams. I'm building a 496 right now for a street/strip deal also. Its knarley for the street but it will get it done for the little its drove.

 

thanks i'll be giving them a call tomorrow.

 

No, it has a 5200 stall, slicks and open headers, the ramp speed of a solid roller is no comparison to a flat tappet.

Have all your info with you when you call Lunati. most importantly what RPM do you want to operate at?

 

The reason your builder spec'ed that cam is because of your static Cr. Yes, you can make some HUGE HP numbers at the top with those heads and a big duration cam, but it will be a serious dog down low and mid- and will have a relatively narrow powerband with that CR. But I assume that if you paid for all that hardware, you want to hear it scream, so maybe you don't care about driveability- just the "sweet spot". With that much motor it might not even matter.

 

so do i drive it or make it scream? Raise compression,for more power or because of head size i cant get the power i thought for street/strip?

 

i saw your video of that 505 at the track WOW! she moves! nice work on your other cars aswell.

 

you can have both, your cam manufacturer can make the setup work. My heads are small and I make it work with the right cam.....

 

Try checking out www.speedomotive.com . They have the specs on their 496 with a hydraulic cam and oval port heads that put out 550 hp as a comparison.

 

i agree with the comment above, Your heads are awful big for the compression you are running hence the small cam. We built a 10.5:1 540 with big heads and big cam and it was the laziest engine I ever dealt with. My brother on the other hand built a 540 with 13.5:1 compression 360cc heads and stupid big cam and drove it on the street with pump gas as long as he didn't get really crazy with it.

Call the cam company and they will give you the numbers and set up to get you decent cranking pressure and you will be fine

 

If you wanted 600hp street motor then you shouldn't have started with a 496. Bigger is always better for that type of goal. A 540 or 572 (even with 'lesser' heads) would have got you there.....anyway....

If your really honest with yourself and the guy at the cam company with its intended use (mostly street and occasional strip) then I think you'll find that the cam your builder picked is not far off the mark. With the aluminum heads and that compression ratio your running pump gas all day along and quite possibly the cheap shit to boot.....not a bad deal when feeding 496 cubes. Although the runner volume seems big those heads still have good flow numbers at low lift....and the extra displacement downstairs is gonna pull air on those ports like a fat kid on a chocolate shake.....so the ports aren't all that killer in the realm of overgrown BBC's. That cam is not going to have the 450rpm thumpy "hamburger stand" poser idle but you won't be passing it off as a stocker either. I think your builder's choice is a decent compromise considering the compression ratio, cubes and intended use..... you can always put more cam in it later and if you were to do that you'd want to take advantage of a roller cam at that point anyway. I think it'll be 'snappy'.

-Bigchief.

 

hey thank you guys for the great feedback, i feel better about the cam the builder chose, for now i am waiting to here back from lunati. I will keep everyone posted of how it goes.All of you are awesome THANKS!

 

just setting up my 489 BBC oval port pro comp , just street play , Lunati 50250 300/310 242/ 252 .595/ .612 any one run similar set up . 55 chevy post 3700 lbs 3000 stall 3:23 gear cruise car shows .

 

The heads are a bit big for that and the compression is a bit low. Have you already purchased your other parts? I would expect that combo will have an aggressive but not killer idle and pull really good in a street car, but leaves a lot on the table for a race motor.

My own BB is 460 cubes, 10.4:1, AFR 305 heads with a custom solid roller. 258/268@.050 .685/.663 lift Victor Jr intake and old 1000 cfm demon. Made 642@6900 on the dyno. The heads are actually too big but I bought them with the intent of stepping up to 4.25 stroker and .100 overbore (505 cubes) with more compression. I'll run more cam in it then too.

Devin

 

A few older posts here 4 petal were you referring to my 489 set up the heads have a larger chamber then was planning , The engine has been running for two years with a comp x274 hydraulic flat tappet edy air gap 2 plane , 781 cast heads , so hoping angle mill slightly and thin crush head gasket will put me in the 10.1 -10.5 on pump gas 32 34 deg total timing . range on spec is 2500- 6500 which seemed like a larger rpm range . Thanks for any input

 

well if he specd that cam because of the compression ratio, WTH would he pick a 110 LSA?

 

Wonder what ever became of the OP build, and what cam he chose? Always wonder why these people never return to tell what they did, or how it worked out after 4 years?

 

Shoebox- My response was aimed at the original poster.....missed the fact that it's been 4 years since he started this thread. Duh. Wonder how the motor worked out for him?

Devin

 

With those heads, you total timing can be as high as 42-43* It will show higher if running a vacuum advance dist, but that is ok due to it removing advance when on the throttle. Set your total to 38* with the vacuum disconnected and plugged. Do you know how to set total timing? Not a flame, just a question I can answer for you.

The combustion chambers are very inefficient on old iron BBC heads, therefore, they need timing.

 

good info anyway thanks , There is a lot of bad comments floating around about pro comp heads , a shop in Lethbridge has one of the best head men in the business there are going to angle mill the 300cc port , knocking chamber after cc head to achieve 10.5 to 1 Don't know much about lunati street strip series 50250 2500-6500 rpm 300/310 242/252-- .595.612 should wake up the baby stroker not a daily just a evening blast here and there . should still have some girl friend driving , street manners , still rattle windows and chase done a stang now and then

 

sorry guys I posted 4 years ago not knowing much about a thread, and with five kids its taking along time for my 496BBC to get this far especially since I have done a full tubular front suspension with coil overs on my 65 cutlass. I ended up going with a lunati 60240 cam, yes a bit small but the engine has got 10.5 comp. Nutter racing put it together for me and picked the cam based on what wanted, so I put the money into the scat stroker kit and dart pro1 heads hoping they will last till kids are little older then we can play around with solid rollers! also while ive been gone I have had a couple trannys built, started with a 700r4 fully built but sold it due to buddies telling me it wouldn't last so my builder has finally got my th400 done. all my hard work has caused me to have back surgery so as I heal I will start working on my car again and this coming year should bring lots of parts to get it fired up so thank you for all the guys knowledgable advice! keep you all posted

 

Here's my 65 cutlass F-85 , 496 bbc with scat stroker kit , dart pro1s, lunati 60240 cam. Last pic is my CPP tubular a arms with Q A coil overs. Hope my pics load right.

Posted using the Full Custom H.A.M.B. App!

 

Before you get jumped on for an OT car, let me say it looks great!
shoebox55 mentioned Pro comp heads, they are not the same as the Dart Pro 1 heads on your build. Pro comp has the bad rep as an "offshore'' copy of American made stuff.
Good idea to build a bottom end strong enough to take the power.

 

Looks good.

 

Why is the car OT ? Is it because of the front end parts.

 

"If you've come here to discuss anything other than Hot Rods or Customs built in a style representative of 1965 or before, you've come to the wrong forum."

 

someone needs to clarify ?

 

One reason for the cutoff is to exclude musclecars. Once they made the scene, anyone with a checkbook could buy a car that was often faster than homebuilt hot rods. Although hot rodders seized upon the new Detroit engines and powertrains, changing the face of drag racing. Sorry, but the Cutlass is just a little too "new" for the hamb.
MII & tubular a arms up front aren't liked very much here. Check out the ''sticky'' threads on page 1 for more clarification. Nobody's hatin' on ya. Ryan has been cracking down lately. The HAMB has become huge and there's a concerted effort to keep it pure and under control. One well known member was banned, mercifully an unheard of 7 day suspension. Usually once someone is gone that's it.