Help me choose a cam for a 350

**Mr. D** · 05-28-2010, 06:28 PM

I need some opinions on a cam for a 350 L-82 type engine for my '56 Chevy Wagon. It's a Cruise Night Car not a racer, so I just want an engine that feels good away from the light to 5500 rpm. I'll be running (64CC Alumn heads 1.60/2.02 valves 190 CC intake runners), roller rockers, Edelbrock Performer Manifold & Edelbrock 600 CFM Carb.

I've been happy with many engines with a GM #3863151 350 HP 327 cam. I'm considering the GM #3896962 cam of the L-82 engines as a better choice for a 350 CID.

I've been told that the Competition Cam 268H is a good alternative to the GM L-82 Cam, but I'm concerned about it having enough vacuum to operate power brakes properly. The lobe center angle on the cam is 110 while the GM cams are 114 which I've been told will reduce vacuum to give it a roll in the idle like old iron.

Does anyone know if the Competition Cam 268H will have plenty of vacuum for good power brake use, or would I be better to stick with the GM #3896962 cam of the L-82 engines. I've always had good luck sticking to GM part combinations rather than mixing and matching. GM puts allot of time making combinations that work well in general use.

Also, what is a good source to buy GM grind Cams at a good price like the GM #3863151 350 HP 327 cam and the GM #3896962 350 L-82 cam?

If you have a good recommendation for a cam that is like those I mentioned BUT BETTER lay it on me!

Thanx in advance for your opinions,

**garygnu65** · 05-28-2010, 06:58 PM

I feel gm cams are old and under achieving.I recommend comp cam 249-12-242-2.also look at the ICL when comparing cams.I have seen this cam used in a few budget builds in magazines ,and it dose better than the other cams tested.go to compcam website and read all the tech articals on this cam.also google the part number for test results.

**Mr. D** · 05-29-2010, 12:39 AM

Thanx for the comeback!

I'm leaning towards a cam with a lobe separation angle of 112 to 114 to keep a good strong vacuum for the power brakes. It seems many cam makers are going with 110 degrees to create an "old school" rough idle for cruise night fans. I like that sound too, but I just want the best running cam from idle to about 5500. I built a number of 327's with the GM #3863151 cam and loved them. The engines ran very strong on pump gas without a problem. The GM #3896962 is supposed to be a 350 CID version of the GM #3863151 cam.

Anyone have an opinion on the Edelbrock 2103? Sounds like it might be a good cam for a 350 with a 700R tranny.

I appreciate the opinions,

Mr. D

Here's the older beater I need the cam for! Some people just can't afford newer cars like you guys!

**pajeff02** · 05-29-2010, 05:19 AM

We built up a healthy 350 for our '74 L-82 Corvette a few years ago. I upgraded to Vortec heads and a Performer intake, which are both slightly disguised. Obviously, the bolts stand out as being incorrect, but so be it. I would have to dig back into my literature to see what cam we put in it. I wanted a bit of lope and good off idle power as the car will not see any real high rpm use.

**Firebirdjones** · 05-29-2010, 07:14 AM

Owning a 56 nomad myself they are heavy cars. If you want a cruiser I'd stay tame on the camshaft.

I'd also don't see a reason to go with an old GM grind camshaft. The lobe designs are lazy compared to todays camshafts.
If you like the old L82 cams or the 350/350 cams but want a newer lobe design with a faster ramp profile (that won't affect drivability) I'd look at Comp Cam Extreme Energy camshafts.

For your application and from what you have said I'd stick with the XE262 grind. with .462/.470 lift and duration numbers of 218/224 at .050 it's pretty tame for a 350.
Even with a 110 intake lobe sep it will idle smooth in a 350. It's ground with 4 degrees advance as well (106 ICL) so that helps with low end and will also smooth the idle.
To give you an idea, I run this camshaft in a little 307 in another car,,,,and it idles pretty smooth in that engine as well.

In a 350 it would fall right where you want the rpm to be. Would be good to 5500 but you could stretch that to 6,000 easily if you wanted.

**Mr. D** · 05-29-2010, 02:40 PM

One concern that nobody has addressed is the vacuum for power brakes. I understand that when the LSA number goes down you loose vacuum pretty quick. That's why the GM cams are usually around LSA 114 for driveability.

Anyone have any experience with the Edelbrock 2103 Performer Plus?

Duration at 50 degrees 214/214

Lift Valve: intake/Exhaust 442/442

Lift Cam 295/295

Lobe Separation: 112

**Firebirdjones** · 05-29-2010, 07:50 PM

I would stay away from the wide lobe sep cams unless you are running fuel injection.

Carbed engines make best power with tighter lobe angles.

As far as vacuum is concerned, as long as you run 12 inches or more at idle it'll be just fine. Keep in mind, while cruising vacuum is higher (around ~20).

I can tell you that little XE262 I listed makes 13 inches of vacuum at idle in a little 307. In a 350 it would make 15 inches or better when tuned right. More than enough for power brakes.
Also keep in mind, it's not just the lobe seperation you need to consider when looking at vacuum. The amount the camshaft is advanced will affect vacuum just as much, because the intake valve is closing sooner. The XE262 has 4 degrees advance already ground in.
If I were you, I'd install the cam 2 degrees advance on top of that for a total of 6. This will smooth the idle even more, create a tad more vacuum, and make more bottom end torque with a slight sacrafice of top end power. It also moves the intake valve closer to the piston, but with this small of a cam, piston/valve clearance isn't that much of a concern.

Retarding the camshaft will have the opposite affect of all those things I listed.

As far as the performer camshaft, yes I've used it in a couple of applications. Once in a friends Jeep Wagoneer 360.
I also currently run the performer camshaft and intake package in my 79 1 ton pickup with a 454. I use it for towing a 10,000 lbs. trailer, and this package seems to make enough grunt to satisfy. But it runs out of steam at 5,000 rpms. Runs good enough to propel the truck to 14.70's at a 5,500 lbs. race weight. Not bad for an old brick. It idles with 16 inches of vacuum in my truck.

Quite honestly I find it a tad on the small side. I did this before the XE grinds and better lobe profiles hit the market many years ago. Otherwise I would have went with something a little different. In any event, I plan to refresh the motor at some point, and probably go with a smallish roller setup ground to make torque and peak around 5500.

**Mr. D** · 05-31-2010, 02:01 PM

Any opinions on this cam for my needs???

**Firebirdjones** · 05-31-2010, 07:50 PM

Ya, that appears to be the performer camshaft.
My opinion, it's rather small, even for a stockish rebuild, and uses old lobe profiles.
I'd look at better ramp profiles if it were me and take advantage of those 190cc aluminum heads you are running.

**Mr. D** · 05-31-2010, 10:42 PM

I'm not clear on what you mean by lobe and ramp profiles? Can you elaborate. What are the numbers I should be looking for?

Also, can you refer to my concern about having good vacuum for power break unit? I'd rather stick to 112 to 114 LSA for good power brakes. I don't need to have the fast car on the street.

Thanx

**Firebirdjones** · 06-01-2010, 06:08 AM

Ramp profile refers to the shape of the lobe. Alot of the older camshafts have a very slow ramp, in which it opens the valve slowly and is open for a shorter period of time.

Roller cams embraced this technoligy. Being a roller lifter, cam manufactures were able to design lobes that opened and closed much faster, and stayed open longer. Not to mention the lost friction benefits.

Within the last few years they have done similar lobe profiles with flat tappet camshafts. They are limited as to how aggressive they can be due to the flat tappet lifters. Especially SBC with their small diameter lifters. But it's still something to take advantage of when shopping for a new camshaft. Comp Cams XE line has these types of lobes.

As far as vacuum, anything making 12 inches or more will support power brakes. You can do that easily with a 110 lobe sep camshaft. Almost all of your catalog camshafts will have 4 degrees of advance ground in. Which also improves vacuum, idle quality, cylinder pressure etc...
If you stay around 220 at .050 intake duration numbers it will idle smooth when tuned even on a 110 lobe. Which is why I recommended the Comp Cam XE262 grind. For a 350 it is smallish, makes good low end and mid range power, and will run your power brakes easily.

If you are really dead set on a 112 lobe cam, Crane is one of the few that grind their off the shelf cams with 112 lobes. But with a 112 lobe, you will be giving up some low and mid range power for more up top.

**Marc 85Z28** · 06-01-2010, 07:51 AM

Definitely the XE lobes!

I've had the 268, 274, and 284 all in my Z28s 355 over the years (all on a 110 LSA). The 268 was fairly mild. Noticable lope, good vacuum, good idle, no drivability issues. Good power from off idle to 5500rpm with the Performer RPM. The 274 still had enough vacuum to run power brakes and HVAC controls without problems, but the 284 required me to run a large vacuum resevoir.

The XE has an aggressive ramp rate which helps with vacuum.

A lot of people have issues with the break-in on these cams. Flat tappets normally require care during the break-in, but IMO these lobes require a little more. I ALWAYS use new lifters, lightly hone the lifter bores with a wheel cylinder hone, and use a conventional oil designed for cam break-in (most modern oils lack the necessary minerals for flat tappet break-in). Royal Purple makes a good one.

**Mr. D** · 06-01-2010, 12:09 PM

Thanx for the education guys!

Mr. D

**Mr. D** · 06-01-2010, 12:34 PM

Originally Posted by Firebirdjones

Which is why I recommended the Comp Cam XE262 grind. For a 350 it is smallish, makes good low end and mid range power, and will run your power brakes easily.

Is the XE262H the same cam that you are recommending?

Thanx,

Mr. D

**Firebirdjones** · 06-01-2010, 02:37 PM

Originally Posted by Mr. D

Is the XE262H the same cam that you are recommending?

Thanx,

Mr. D

Yes sir. Off the top of my head....

XE262H....

218/224 at .050 duration and .462/.470 lift
110 lobe sep with 106 intake center line. Very mild for a 350 and mimics the old 350/350 HP GM cam as far as lift and duration go, but has the modern ramp profiles. I wouldn't steer you wrong, for what you are looking for this cam falls into that realm, and will run power brakes easily.

**Firebirdjones** · 06-01-2010, 02:40 PM

Originally Posted by Marc 85Z28

Definitely the XE lobes!

The XE has an aggressive ramp rate which helps with vacuum.

A lot of people have issues with the break-in on these cams. Flat tappets normally require care during the break-in, but IMO these lobes require a little more. I ALWAYS use new lifters, lightly hone the lifter bores with a wheel cylinder hone, and use a conventional oil designed for cam break-in (most modern oils lack the necessary minerals for flat tappet break-in). Royal Purple makes a good one.

This is correct. Follow break in procedure and us either the GM break in additive or the Comp Cam additive available for about ~$8 or so along with a good oil and you'll be good to go.

**Mr. D** · 06-01-2010, 04:18 PM

Well Guys,

I took your advice and ordered a Comp Cams XE262H. With roller rockers, 64. CC. alumn. heads, Edelbrock Performer Manifold and a new Edelbrock 600 it should get me to the Cruise Nights and back. I don't need it to be too fast. I've got that unmentionable "Furd" car I'm putting a Rousch super charger on to go fast (435 hp/400 torque). If that breaks I just take it to the dealer! Not as easy with a '56 210 Wagon so I'm careful with this one.

Thanx for the Advice,

Mr. D

My ride when I was in China: