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Discussion Starter #1 (Edited)
Hello everybody. I am in need of your guy's opinion and thoughts on my current set-up. I recently had a custom ground camshaft spec'd by a very reputable engine builder for my 540ci BBC. I gave him a list of what my engine consisted of and what i intend on doing with the car. I told him i would like it to haul ass on the motor, run on pump gas, see some street time for cruises and what not, and may put a fogger on it in the near future..probably around a 250-350 hit, nothing crazy big. He got back with the specs for the cam a few days later, which to me, seemed awfully big. At this point, i may have emphasized i wanted the motor to haul ass more than i want it to be street drivable. However, i did not want to second guess his expertise and disrespect him, so i bought the camshaft as he spec'd it. I guess when i told him that the car will see street time he didn't know that i meant that i wanted to drive it a thousand or two street miles and not tear up valvetrain and wear stuff out, not his fault.

Anyways, from a few of my racing buddies that i have spoke with say that my valvetrain probably will not last over a few hundred miles on the street with how big the cam and duration is with this new cam. The engine builder told me the cam ramps are not too aggressive and even with the given lift and duration, it should not tear up the valvetrain. I want to get your guy's opinion on this camshaft. I have post the entire cam card below and my engine's combination. Any help is appreciated. Thanks.

PS - Any estimations on it's power output would be nice too, thanks!

PSS - What would be a good rev limit for my set-up between good power output and safety of the engine components?




COMP CAMS - custom grind, 4/7 firing order swap

Grind # CB 1816B / 1320B R 110.0

Valve Adjustment: .018 intake, .020 exhaust

Gross Valve Life: .800 intake, .748 exhaust

Duration .020 tappet lift: 314 intake, 332 exhaust

Valve Timing Open @ .050 OPEN CLOSE
intake:32 BTDC 68 ABDC
exhaust:78 BBDC 34 ATDC

These Specs are for cam installed @ 108 intake center line

Duration @ .050: 281 intake, 292 exhaust
Lobe Lift .4710 intake, .4400 exhaust
Lobe Separation: 110






The engine set-up is a 540ci BBC. I know a lot of things come into play when it comes to compression ratio (cam, etc.) but was told it should be around 10.5:1, pump gas friedly.

WORLD Merlin III RACE block, 9.8 deck, billet splayed mains, ARP studs
Clevite TriArmor coated bearings
Dart 355cc Pro 1 CNC heads with triple valve spring/ti retainer upgrade, ARP studs
JESEL shaft mount rockers
COMP CAMS belt drive
ISKY RedZone EZ-X solid roller lifters
Smith Brothers pushrods
Lunati Billet crank
Lunati Billet rods
WISECO pistons
Total Seal rings
ATI damper
MSD pro billet distributor, locked out
MSD 7531 Programmable Digital 7, HVC II coil
Hooker SuperComp 2 1/8 headers
Edelbrock Super Victor (just matched to the heads, no porting)
Holley 1250cfm Ultra Dominator
Milodon drag race oil pan with passenger-side kick out
Milodon oil pump with extreme pick-up


Also, if you can give me an educated guess on how much power i should expect this set-up to put out that would be appreciated. Thanks guys
 

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I loaded your specs in my DynoSim5 software and it calculates the following.
Without spray peak torque is 589 ft/lbs @ 5000 rpm and peak Hp is 629 @ 6500 rpm
adding 300 hp of spray yeilds peak torque is 870 ft/lbs @ 5000 RPM and peak Hp is 921 @ 6500

As far as that cam being too big it really depends on the ramp profile.
An option on the street is to run 1.6 ratio rockers which will knock the lift down to .736 in / .684 ex
 

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I would say it is a little too much duration for the compression that you want to run.I used a Bullet grind that was close .825/.780 280/290 @ .050 on a 111 with 14 to 1 comp in a 540 with a Dart 335 and a 1050 that made 918 @ about 7500 rpm. I think for the compression you want to run ,that cam needs to be at least 10 -12 degrees smaller at .050.
 

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seems you are asking alot......haul ass on motor and spray-and be VERY streetable.i say bump the compression to 14 to 1,run some 110 on the street with a couple degrees of timing pulled and spray the shit out it at the track....:).......i would also be checking valve springs before track use after street time.i ran .800 lift on the street and strip and springs would last the full season-1000 miles,100 runs-speed safely!!
 

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I dont think it will kill valve train in a 100 miles umless it already has issues. You can get by with the lift but the duration is to big if its a heavy street car.
 

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Did your engine builder use actual flow numbers or just advertised? Or did he even use flow numbers?
Those heads are a bit big for a 540 and that's a very big cam for your app. I just did a 540 pump gas deal with a custom grind, 260's/270's @ .05, 730ish lift, 108, and we're hoping for 800-825hp on pump gas at around 6700. I also question the triple springs.
 

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First let me say damn that is a very nice build, but man those heads are big, espically if you have a heavy car,
 

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Discussion Starter #12 (Edited)
Thanks for all the replies guys. I felt the cam was too big too but i didn't want to be a jerk and question him on his selection. Looks like i will put the cam up for sale and get a more properly sized one. Like i said he may have not understood what i meant when i said i wanted to drive it on the street. I do not care that the cam is rowdy and what not because it is a 'racecar', i just don't want to be changing valve springs and lifters every few thousand miles. If those things last about 2500 miles, i'd be happy.

On the valve springs, when i bought the Dart 355cc Pro I CNC heads, they came with dual valve springs/ ti retainers that they claim are good for .790 lift. I was expecting to run this .800 lift cam so i went for the triple valve spring option. I don't necessarily have to run them however so i can always swap them out for the duals. The heads are how they came from Dart and will remain that way as far as the porting and CNC work.

The car is a 70 Chevelle, so it is relatively heavy. It's pretty bare but all steel, 12 point cage, motor and mid plate. I would say it weighs 3500lbs.

Transmission is a TH400 and the rear end is a 9". The converter currently flashes to about 4200 and the gears are 3.90. I AM WILLING TO RESTALL AND REGEAR FOR THE NEW CAM. Which was also what i told my cam guy.

Now that you guys know the set-up of the car/engine, can you recommend a good cam guy for me to go to for my new camshaft? The plan is to obviously make the most power with my given constraints... 10.5:1 compression ratio, pump gas, and will not trash valvetrain for 2500 miles of driving, plus the possibility of a fogger. PM me if necessary. And again, thanks for all the help!
 

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Those heads were a bit too big on my 540 race motor, let alone with your weight and cam on a streeter.
 

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Heads cost more than a camshaft. For him to sell the heads and get "smaller" heads, he will be out more money than just a camshaft and maybe valve springs. The best option is a custom camshaft to make the best of what he has.
 

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Discussion Starter #17
I don't really have a specific goal but i hope i am not being too greedy to hope it will run a high 9 naturally aspirated.

I am not class racing or anything so i really dont have any restrictions. Its a stock suspension, 29.5x10.5W slicks, AFCO coilovers.

I would like to go as fast and make as much power as possible with my given constraints. My low 10.5:1 compression, pump gas, and valvetrain needs to last around 2500 miles.
 

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I don't want to hurt your feelings but I don't think it will go anywhere in the 9's without the nitrous. I would say with your combo it should be in the 10.20-10.50 range. I hope it does better for you but it's going to take some pretty good power to push a 70 chevelle into the 9 second range. Michael
 

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I feel that you have the makings of an easy high nine second combo. I have a similar weight chevelle with less compression and cubes and too big a head as well as a cam and converter setup for spray which my broke ass never got to use and i went 10.05 at 133 on 93 octane and 6 yr old 10.5 tires. The rest of my combo was much milder than yours as well. Cam it right( fairly short int. duration with lots of lift ) and you will be pleased. To say you have a 10.50 combo is ludacris.:rolleyes:

Joel
 
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