Can you guys give me some recommendation on cam selection. I know I want to run a solid but what size and from who? I plan on running either the Edelbrock heads or the GM aluminums and hope to keep the compression at 10:1 or a little lower. This is a weekend car so I want something with a good lope to it but not extremely radical. Any advice? :cheers:

 

I am not going to give you a specific grind but for a big block I have preferences. I think .244 @ .050 is very mild and prefer something like 256@.050 intake and .264 exhaust with around 108 lobe centers. For lift I like around .625. A cam of this size has poor idle vacuum but alot of mid range and top end. The .244 with 112 lobe centers gives good vacuum but poor mid range and top end. For the money flat tappet solid is the best deal and little maintenace. I have had good luck over the years with Crane cams and lifters. My latest roller is Comp cams but it is no better then my old solid flat tappet and cost 5 times the price.

 

What would be the largest amount of lift and duration before you would have to worry about hitting a piston on a BB? Since this is going to be primarily a street driven car I want to keep the power in the low to mid range area.

 

The cam I liked the best was a Crane F 256/3634-2s-8. It had 256@ .050 intake and 264@ .050 exhuast with a lift of .618 intake and .648 exhaust. with 108 lobe centers. This cleared the stock 11 1/4 compression pistons but you have to worry about the valve guide to retainer clearance. This exhaust is a little excessive since alot of heads quite flowing at this lift.
I really liked this cam for it's mid range and top end. The idle vacuum would be too low for vacuum power brakes but this cam easily beat my expensive comp cam roller with 244 @ .050 and .623 lift and 112 lobe centers. Lingenfelter calls this a stout roller cam for the street but I find it very mild.

 

The best thing that you could do is post your total setup. then let the guys with desktop dyno run simulations as to what works best with your parts

 

Or post your setup to Comp cams, Crane, Crower etc.. and let them recommend the cam.

I will choose a hydralic roller with ~230@.050/285@adv dur. and .550- .600 lift for my setup with C/R 9.3.
My goal is a reliable, maintenance 'free' 500 HP street engine. :cheers:


[Modified by Lasse, 9:19 PM 10/31/2002]

 

What kind of money are you looking at for the roller setup? I am assuming a good bit more than what a solid lifter valve train would run.

 

Hydralic roller:
cam $260
lifters $300-$400

Yes, it's a good bit more, but you got higher torque, smoother idle and more vacuum (faster open/close duration).

 

BlackRat, I used a Crane hydraulic Powermax cam with my 467 motor, I was thinking about going with a more radical cam but this one is a 296-2 grind with 236 and 246 duration at .050 and 553 and 571 lift. My compression is 9.5-1 and my heads are Merlins. This combo really rocks, people cant believe that I only have 9.5 compression. Stand behind my car and it just about kicks you on your a@#! Check out the Crane sticks I sure like mine! :cool:

 

Is this a custom grind? Am running same cam, but lobe centers are 110, and are advertised as 110 lobe centers

 

the biggest item to determine what cam to use is if you are going with stock exhaust manifolds or open headers. that is why the L-88 cammed engine makes a 100+ more HP with open headers vs closed stock exhaust system. :chevy

 

I got the grind number from an article from Lingenfelter on a stout big block for the street and he called this a stout roller street cam. Comp cam grind number CB280-2/288-4R 112. I went for it at a cost of almost $1500. The cam was $400 CDN, the lifters $400, springs, 2 sets of retainers, keepers and a used stud girdle $300.
This cam does not pull in the mid and upper range as well as my $160 dollar flat tappet Crane cam. For the dollar flat tappet cams are better. If I didn't have $1500 in this roller I would change it back

 

I'm not sure what Lingenfelter had that cam in, but it is definitely pretty mild and is NOT the one that most people refer to as the 288* Comp Street roller. I ran the 288/288* adv and 244/244*@.050 .623/.623 on 110 LSA version and was amazed at how well it ran for such a short duration cam. It peaked Hp at 5850 rpm on the dyno but only dropped 6 hp at 7000 rpm. Absolutely unreal rpm spread. It was still pulling hard at 7000+ rpm yet idled at 14" vaccuum in a 427 with a Dominator on it.

Otherwise I'm with you. The best street solid flat tappets have been in the 255-260@ .050 range and right around .600 lift give or take .020. I like running those cams on 110 LSA which allows you to get by with a little more duration and still be streetable. You can get down to the 106-108 LSA, but they get pretty "rumpy" unless the duration is short. You get lots of overlap otherwise. They do Sound tough though...but unless you have some compression, be careful.

A 112 LSA will really smooth out a cam, but be careful that you don't kill off some needed overlap. I would only use it on a pretty healthy one and probably only on a roller. My 540 has a 262/273@.050 on 112 LSA that really sounds pretty mild. But it has pretty aggressive lobes and I get plenty of overlap.

Check out the Crane 134691. I've used that cam at as low as 9.8 compression with auto's and sticks. It will pull well past 6400 with oval ports and 7000+ with rectangulars. It sounds strong and is easy on valvetrain parts. It can easily run 11's and still drive cross country. You will want some good rockers. Rollers preferably, but good long slots will work. Use good springs and otherwise you'll be fine.

I don't know what pistons you have, but be careful with 2.19 valves with the replacement type small dome ones. They have deep enough pockets to handle around .600 lift ok usually (duration and LSA and lobe centerline will get you in more trouble than lift usually), but when you install 2.19 or larger intake valves they get REAL tight around the outer edge of the pockets and can just kiss the edge of the valve. I've seen a few dropped valves due to this over the years. Easy to fix with a dremel tool, but just look out for it. 2.06 valves do fine.

Big blocks like lift and anything under .580-.600 is giving away power even on oval port heads.

Rollers allow you to do it a couple of different ways. Depends on how you look at it. You can run a bigger cam and it will idle/drive like a milder one. You can also look at it from the respect that you can run a milder one and it will REALLY idle and drive well, but run closer to a larger one. Typically you can compare say a 250* roller will idle/drive like a 240-245* flat tappet. It will also run closer to a 255-260* flat tappet. Until you get into the 245-250*+ range, a flat tappet will usually suffice, unless you are trying tomake an EFI setup work properly and still make power. In that case, a roller is advantageous with a much smaller cam. You need strong vacuum signals with them so a roller lets you run a milder cam that will hold vacuum and still run strong at high rpm.

Also remember that it takes about an 8-10* larger solid cam to compare with a hyd. cam. The reason is the amount of duration used to take up the valve lash (clearance ramps). Net result is the same. So a 250* solid will idle/run similar to a 240-242*or so hyd. The solids advantage will come at higher rpm where the hyd will start to choke up. And often the solid will make more low end power because of the clearance ramps also. The opening and closing points will be somewhat different.

Just a few things to think about. Cams are a very involved deal. The more I learn, the more I find out what I don't know!


JIM

 

Ditto with the above statement....just pulls and pulls all the way past 7K R's with 14-15 inches of vacuum.

Cam is not that expensive, I paid 625.00 for the cam, lifters, springs.

Norval, I don't know what cam you're talking about, but that does not come close to the description of the cam I'm running, not even on the same planet.


[Modified by GDaina, 9:03 PM 11/1/2002]

 

Another awesome BB cam thread! All of us rookies really appreciate you guys layin all of this knowledge on us! :cheers:

Gdaina - What block and heads are you running? Was that a 502 to start with or something else? I was told by the Comp support folks that I couldn't run the 288 cam because of my power brakes and other things. This thread seems to contradict that advice. That is the cam I've been eyeing for the last year! I also just found out that I have JE pistons with a casting number that they only recommend for 500 plus cubes so I may have more than I thought! :D Also, how in the heck do you keep that thing goin staight with a 3.55 gear and the big 3.20(?) first gear of the DN (Richmond) 5 spd? Anyway, I won't know exactly what to do until I pull the heads which will have to wait until the $$ flows again. Thx for the valuable info! :seeya


[Modified by Marks69BB, 7:56 PM 11/1/2002]

 

I think when talking about cams, and their mild or aggressive nature you need to consider the application. The cam Norval is refering to is a mild solid roller, check the Comp cams catalouge and you will see they only make a few Solid rolers smaller than that one. That being said it is not a mild cam, solid rollers are not supposed to be mild, they are all about sacrificing a certain degree of streetability for all out performance.

I am running what is basically a newer version of that cam in a daul plane 460 in motor. It is the XR 280 R .646 .653 242 and 248 at .050. My motor made 450 rwhp (6000) and 470 rwt (4100) with stock Edelbrock Ovals and a worked annular discharge 850 DP. I will be going to something in the 250 + at .050 intake and 255+ exhaust, after I have the heads and intake hoged out. I have power brakes and they worked fine.

 

Yes, 502 bare block, and the older GM 077 Aluminum Heads.

Yea the first gear is a 3.27, and with the 3:55's it's like having 5:13's in the first four gears....ain't life beautiful? A never ending grin is what I have on my face.

I could not believe the vacuum gague, when it fluttered between 14-15 inches of vacuum. One thing to keep in mind, all my vacuum hoses are new.