im am re-doing the top end of my motor this winter. i spoke with one of the reps from AFR. i m going to be placing an order for the AFR 195cc heads with 74cc combustion and the L98 angle plugs. the rep told me that my cam should be around around 230 duration and around 500 lift. i need help picking out the right cam. i don't know that much about cam. i understand lift and duration but for some reason im have a hard time picking the right cam. i have the AfR catalog and it says the max lift for these heads are 550. this car is emissions delete so i don't use the smog crap. i want to be able to drive that car on the street when i want to(not a daily driver). i told the rep from AFR that i was looking to run mid to low 12s at the drag strip and he said that i should have no problem. my car is a five speed manual trans with 373 grears. im worried that if i pick a cam its going to be to big and when i start the car for the first time, the valves are going to hit the piston. then i'm reall f*cked. thats why im seeking professional advise. any help would greatly appreciated
if you need more specs just let me know.

PS. HAVE A HAPPY THANKSGIVING

 

Your best bet would be to get ahold of the cam manufacturers, tell them what you've got, what you want to do, and follow their recommendations.

Comp is especially good at this. But, you need to be specific about what things are "must-be" and what you're flexible on.

 

Are you looking for a Hyd flat tappet or a hyd roller, or solid lifter cam?

I'd move up to a Performer RPM intake manifold or a Victor JR.. Either will fit under the hood. With the right air cleaner.

You don't need to worry much about the valves smacking the pistons until you get up to a fairly healthy cam.
If you're that worried about it why not check valve to piston clearance before you start the motor. It's not that hard to do.

How rough of an idle do you want? Is gas mileage an issue?
Do you want the easy maintainance of a hyd cam or the power/rpm and sound of a solid cam?
What power accessories does the car have?

Your 400 is very simular to the one I'm just now completing.

Have some ideas for you to consider but need more info on
your car and your intended usage.

Am thinking along the lines of a Comp Cams Extreme Energy XE284H-10

http://www.compcams.com/Technical/Ca...L/128-169.html

 

i have hyd flat tappet lifters now and i think im going to stay with that setup.

i forgot to mention that i am going to upgrade to the performer rpm air gap manifold. hood clearance is not an issue i have a cowl hood.

gas milage is not really a concern. i don't really drive the car that much. idle roughness really doesn't matter. i loved the sound of the older muscle cars. you know that nice lumpy idle that you could listen to all day long . would that time of cam be a bad street cam?

the car has power steering and power brakes. it has no a/c

if you don't think im going to have to worry much about valves smacking pistions then i won't. its just that i have heard of storys were that has happened. i didn't know any of the specs of the engines in those storys. i just didn't know if i had to really worry about that.

thanks alot for the help.

 

As long as you stick with a fairly mild cam, less than .650" of lift or so, you won't have any piston-to-valve clearance problems.

I'd suggest a Comp XE274H with 1.6 rockers. And for your own financial well-being, GET RID OF whatever crap AFR puts on their heads for valve springs, BEFORE you drop a valve or have ohter malfunctions. Last time anybody checked they were using K-Motion, garbage. I'd recommend Comp 987s with the appropriate retainers and keepers and spring cups.

In fact, you'd probably be better off to buy the AFR castings bare, and put your own hardware and valves and springs on them. I'd recommend Manley Street Flo valves, Comp 500 seals, and studs & guide plates from ARP or Comp or Manley.

 

Want that muscle car sound eh?

Why not get a reproduction muscle car cam? That would make the 'muscle car sound' best IMO

http://www.ajgeneral.com/comp_factory_muscle/

 

Well now you have two good recommendations and some solid advice.

Both cams will work well in your car and get you where you want to go. One will have a little more peak HP the other will have more bottom end grunt.
The only way to know for sure which is best is to try both and test in your car.


Comp cams does recommend that you check Valve to piston clearance on a cam the size of the XE-284 or simular.
It most likely will have more than enough clearance but
never assume anything, spend a 1/2 hr and check the clearance during your cam and head swap.


Either of these cams will require a recurving the ignition advance rate.



They both will want more initial advance at idle but the same total timing at high rpm as your small cam you have now.
This involves limiting the mechanical advance travel in the distributor.

The larger XE284H10 will like quite a bit if advance at idle like 20 to 30deg because of its overlap.

both will want about 32 to 36deg at high rpm.

Set your distributor up like this and follow RB's valvetrain advice and your 409ci upgrade should be trouble free.

Might as well buy a complete cam and kit from CompCams ("K kit")
includes cam, lifters, springs etc.

The tech dept at Comp cams is more than ready to help and advise. its free too.

www.compcams.com

 

thanks alot for all the help. do you guys think that the AFR parts on the head are really that bad. would i have to upgrade the valves or just the springs, retainers, ect..i have a budget and the heads take up most of it. if they are really that bad then i guess i'll have to spend the extra cash

what do you guys think of the XE284H. its the next one up from the XE274H. do think the XE284H would be to much. then i could bring it up to 6500rpm. let me know what you think. i think im going to give comp cam a call on monday.

also, how do you check the piston to valve clearance.

 

The XE274H-10 has a moderate lopey idle @750rpm but is not hard to live with at all.
Ha a moderate street machine sound with reduced but managable engine vacuum for power brakes.

The XE284H-10 is not too big.

The XE 284H-10 is definatly more aggressive than the milder 274H
It has a bad *** rough street machine-cruiser/street racer idle but is not unmanagable especially with a manual trans. Power will be from 3000 to 6000 rpm It will idle steadily at 800rpm, but rough.
The power brakes may/will be affected. A auxillary vacuum reseivour is recommended.
The trick to living with it is setting up the distributor advavce curve to match.
It (the cam) will rpm to 6500rpm with the right valve springs and antipump-up hyd lifters. ...but.... you'll probably find this motor performs best when shifted right about 6000rpm.
400SBC's are not real rev'ers as a rule. Think torque and power with a 400SBC ,,,not rpm.

peak HP will be right at or just under 6000rpm.


If you want that kind of RPM out of a 400SBC you should be thinking a racey-er street-strip solid lifter camshaft. 6500-7000rpm is no problem.
It will also make more power than a hyd cam.



A good street/strip solid cam for your 409 would be a COMP cams
Tight lash solid cam #12-502-5 grind#280-TL6
Specs are 280/284- 250/254@.050" .530-.540" 106LSA.

Combined with a vic JR intake you can easily buzz it to 6500 if you want. But don't think about 7000rpm , cause the 400 will eat it up quick. Again they are torque motors.
A powerfull street-able but racey combo with 11sec potential.
Periodic valve lash maintience is nessessary.
Favours long tube headers and free-er or open exhaust.


My 400SB is very simular to yours but with ported big valved Vortec heads.
I am base lining my 400SBC combo with the XE284H-10.
I also have 2 other solid cams to try, one smaller (like the 274H) and one larger. (like the mentioned Comp solid)


All these cams will give good results in this type of motor.
Driving impression, and track testing will tell which is best overall.

The valvetrain setup is basicly the same.

 

thanks for the brake down. i think the XE274H would be the better choice for my car. i don't want to have problems with the brakes. i would rather stay with the hyd because i don't want to adjust the valve lash all the time. thanks again.

i should be able to see 12's with cam right?

 

Yes

 

i talked to the tech rep from comp cams and he told me to go with part number 12-254-3. this seems really big what do you think.

 

He's just trying to ensure there is enough "cam" to feed
the hungry 400cubic inch motor.
Like I said they are torque motors and tend to eat up cams as compared to a 350 sized motor.

But the AFR heads flow pretty good, I think the XE284H10 should be as big as you'd need to hit your goals.

The XE274H10 should be enough too.
Just be sure to back it with enough converter, rear gear and sticky rear tires to launch the car hard.


If I was going to go that big as the XE294H10 I'd go with the #12-502-5 solid cam I recommended.

At that point the solid cams have a definate edge.

 

alright thanks alot. i just thought that it sounded really big. i have a manual trans and 373 gears.

 

F-BIRD'88
i was reading another post that you replied to about cams. i was under the impression that a solid lifter cam had to be adjusted every couple of weeks. you said in the post that you only have to adjust them like once or twice a year. now that i hear that, i have changed my mind. i would rather run a solid cam. what would you reccomend for a solid cam.

i was thinking maybe the 294S. what do think. also should i be looking for a cam with the same duration on the intake and exhaust. same with the lift, should it be the same or different.

 

The Comp Magnum 294S would be fine. It's a good cam.

There is no cut and dry answer as to wether you should pic a single pattern cam or a dual pattern cam.

Both work. Which one works best in your motor can only be determined by testing.

A cam with a little more exhaust duration helps top end exhaust breathing and HP on a motor that needs it.

Either will get you down the track, either will get you solidly into the 12's. Possibly into the 11's.

The Comp 294S makes lots of power and revs to 6500+rpm easily.

 

If you need to adjust the lash every 2 weeks on a street motor something is definately wrong.

If you wanna go fast N/A I'd consider the Crane "saturday night special" solid cam. 244/252 @ 050, .518/.536 lift 106LSA. I've seen awesome results with that camshaft. Its also available with 112LSA which will make it more street friendly also. I've seen numerous cars run 11's (and one even 10's) N/A with that (the 106lsa) camshaft. A guy around here goes 11.70's with that cam and stock vortec heads on a 406.

The way I see it is if you have a big motor and expensive great flowing heads why not use them to their full potential? Putting in a baby cam would just seem like a waste to me.

 

Heavy : Hope your taking notes, Solid advice here....

Here is a link to the Crane cam here
You can even buy it in a complete kit form.

Crane Saturday Night Specials

 

thanks alot for all the advise. i have been using this post and message board as a bible for the past couple of weeks.

88IROC350TPI you are right. it seems like a waste of time to put a baby cam in a big cubed motor. thats why i was seeking advice. thank *** for this web site. also is that cam that you reccomended a full race cam. will i have any problems running that cam in a street car.

 

Not quite apples and oranges but just for your info.

We put the XE274 in my friends 69 Camaro, 327, 4 speed, 4:11 rear, Trick Flow twisted wedge heads, Z28 manifold with 1" carb spacer.

Smaller motor) Idles with a nice lope at 850-900 rpm.

Lighter car and lower gears) good bottom end, great mid range and strong top end to 6000-6500 rpm

I don't think you will have a problem with the XE284 since your engine is larger but if your still not sure, I don't believe that you will be disapointed the XE274 eather

Ken.