cam combo:Am I on the right track?

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retsud_043

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I need your opinion on this camshaft.Its duration at .050 is 234 intake, 240 exhaust. Its lobe lift is .331 intake, .336 exhaust (.529/.537 valve lift with 1.6 ratio rocker arms). It has a lobe separation of 108.

This will be going into a 1970 340 :steel crank, resized 340 rods, 9.5:1 .030 KB pistons, U heads w/ 273 adj. rockers 2.02/1.60, 1970 hi-po 340 exh. manifolds, Edelbrock LD340 intake, 800 TQ, MSD 6a with MSD billit dist.

The engine will be going into a 1971 Duster with an a833 o/d,3.55 8 3/4 489 clutch type sure grip and 26" tall rubber.

This car will be mainly a cruiser but will se the occasonial trip to the track.

Any input on this cam for this application would be appreciated.
Thanks,
Chris

specs.jpg
 
should be a nice cam for a 4-speed. maybe low on vacuum if you have power brakes. i would make sure you have a true 9.5 cr i would go closer to 10.25 cr, that cam will bleed a lot of PSI
 
I agree. a little more compression or a little less duration.

I ran a .525"/258 at .050" clay smith solid w/3.91's and a 4 speed, 26 inch tire,10.5-1 comp, torker II 340,625 AFB...it was a monster above 2800...like a light switch...that's when the tires would boil!

If you want it to be a truly drivable machine, you want a little more power down low.

P.S. The power brakes (if you have them) should go away in favor of a nice modern aluminum mopar manual master.
 
retsud043 said:
I need your opinion on this camshaft.Its duration at .050 is 234 intake, 240 exhaust. Its lobe lift is .331 intake, .336 exhaust (.529/.537 valve lift with 1.6 ratio rocker arms). It has a lobe separation of 108.
I apologise for the poor picture of the cam card,
This will be going into a 1970 340 :steel crank, resized 340 rods, 9.5:1 .030 KB pistons, U heads w/ 273 adj. rockers 2.02/1.60, 1970 hi-po 340 exh. manifolds, Edelbrock LD340 intake, 800 TQ, MSD 6a with MSD billit dist.

The engine will be going into a 1971 Duster with an a833 o/d,3.55 8 3/4 489 clutch type sure grip and 26" tall rubber.

This car will be mainly a cruiser but will se the occasonial trip to the track.

Any input on this cam for this application would be appreciated.
Thanks,
Chris
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I would say that it's a bit too radical, considering (as was mentioned) the light compression, lack of headers AND.....that overdrive 4-speed actually has the ratios of a 3-on-the-tree stick in the first 3 gears, meaning......it's a bigger jump between shifts. You're gonna a little more low end grunt. I hope you've got that TQ dialed into the low vacuum setup. I think if you bumped the compression up to stock (10.25~10.5), got some headers and ditched the OD A-833, it would be killer. My setup in my '67 convertible is similar to yours:

'70 340, X-heads (pocket ported), forged flat tops, LD-340 intake, 650 Holley D.P., small tube headers, Isky 280 Mega (480 lift, 230/230 @ .050, 108 LSA) with 273 adj. rockers, standard A-833, 3.91 posi and a MP electronic ign. It rocks!
 
Thanks for the input:thumrigh: The specs I have given are only a thought and not written in stone.... ie. compression ratio, so that can be increased#-oThe only piece of the puzzle that has to stay are the 340 manifolds, and the a833 o/d,due to I have 3 of them and I'm trying to work with what I've got](*,)
This roller camshaft only a thought as of now but I do already have an Edelbrock Performer RPM 7177 and a purple shaft .509/292 cam.
In a previous thread about the Eddy, I was told it was a little on the lacking side(performance wise):dontknow:.
The more opinions about what I should be using for a camshaft the better, I value the combined FABO knowledge:smile:
 
I have a Comp XE268H cam in my 360 and it is a great street cam. Pulls hard from 1500 rpm. Specs are 224/230 @0.050, .509/.512 (with 1.6 rockers) and has a 110 lobe separation angle.

I also run an A833OD with 3.55 gears and have a 27" tall tire. My best 1/4 is a very traction limited (2.2 sec 60') 13.7 at 102mph. Easily a low 13 second car if I sort out the traction issues.
 
I would run that roller before the 509 camshaft. It would definitely idle better than the PS cam. Theoretical lift with 1.5, 273 rockers will be in the 490-500 range, more like 470 at the valve.

Stock exh manifolds run better with wide LSA's. If you are going to run this roller, cut it on a 112 or better a 114 lsa. 108 is too tight for 340HP manifolds.

As suggested, try to get the compression up to the 10:1 range and maybe that would take cutting the heads a bit. Which KB pistons and how far out or down in the hole are they?

Not a bad grind, would make good power to about 6200-6300 with cylinder heads, if stock/unported, likely being the bottleneck.
 
Solid rollers do kick butt but they do require pulling the lifters to check the rollers every year as they don't like long periods at idle, although I do think Comp has a new set of lifters with pressurized roller bearings.

If you still want to stick with a solid roller, that is actually a good choice and here's why: A solid style cam, whether roller or not, will act like a hydraulic cam with 8 to 10 degrees less duration. So in essence you've picked a cam that will act like a Hyd with these specs: 226/232 @ .050" lift. The 108 LCA will preserve cylinder pressure, so that's good with only a 9.5:1 CR although another .5 of CR would only help.

The downside:

1. That tight LCA will lope pretty good and may not have enough vacuum to run power brakes.
2. It will also require some carb tuning and I don't know TQs well enough to help you with that. If you had a Holley, it would be no problem.
3. A better pick for intakes would be the Eddy air gap with that big of cam too.

Let me know if you have any questions. :)

Joe
 
The half point of compresion means nothing in the big picture. 1.5% more power & torque at best. Sure, everyone has a point, more is merrier and at that rate, that cam could use a 11.5-1 true ratio and perform even better if a fuel could be found ... eh-hem... cheaply enuf to use everyday.

If the Dodge trucks in the Crafstman series can make over 700 HP with a 9.-1 engine, I really don't think your worried about a .5 drop over the recomended 10-1 ratio. Beside, the cams duration is not that big and a iron head engine at 10-1 will only carbon up and increase in ratio and octane needs that are not so well met at the pump even with 93 octane.

OK OK OK, he can retard the timing to make it work.... at a loss of power more than a .5 provides I'll wager that one big.

IMO, theres a few things I'd change, but the cam would stay for it's intended useage as described above. If you can afford headers one day, I'd do it to the tune of getting a good 30 hp and 40 lbs. of torque more without batting an eye. Good luck with the T-Q. Take your time with it and set it up as if stock first. Jets and rods are tuff to find. Match a T-Q rod up to a AFB rod, look carefully and measure twice, cut once.
 
rumblefish360 said:
The half point of compresion means nothing in the big picture. 1.5% more power & torque at best. Sure, everyone has a point, more is merrier and at that rate, that cam could use a 11.5-1 true ratio and perform even better if a fuel could be found ... eh-hem... cheaply enuf to use everyday.

Well yes, more compression = more power but it also equals more vacuum at idle and essentialy better driveability which is very hard to quantify as a percentage value and that was really my point. :)

If the Dodge trucks in the Crafstman series can make over 700 HP with a 9.-1 engine, I really don't think your worried about a .5 drop over the recomended 10-1 ratio. Beside, the cams duration is not that big and a iron head engine at 10-1 will only carbon up and increase in ratio and octane needs that are not so well met at the pump even with 93 octane.

Well yeah.... But those engines are not SB LA's. :) There's a great article on these engine in the latest Hot Rod Mag. Making that kind of power with the blocks and heads we use are comparing pineapples to broccoli.

OK OK OK, he can retard the timing to make it work.... at a loss of power more than a .5 provides I'll wager that one big.

10:1 on pump premium should not be a problem with cam @ 226 @ .050,. I'd wager on that, if I had any dough, lol. I'm running 10.2:1 with a much smaller [email protected] with open chamber heads. Granted I'm way above sea level but 13 more degrees of duration and a .2 compression drop from what I have should suffice.

IMO, theres a few things I'd change, but the cam would stay for it's intended useage as described above. If you can afford headers one day, I'd do it to the tune of getting a good 30 hp and 40 lbs. of torque more without batting an eye. Good luck with the T-Q. Take your time with it and set it up as if stock first. Jets and rods are tuff to find. Match a T-Q rod up to a AFB rod, look carefully and measure twice, cut once.
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I agree about the headers, I just don't know enough about the TQ's to comment. I hope I didn't come off like a butthead Rob, that's not my intention. :)
 
1wild&crazyguy said:
I think you can run power brakes with that cam.jmo
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It's possible I guess. I just wouldn't say so in every circumstance. A vaccum can wouldn't hurt. :) I figure he'd be making making 10"-12" with that cam with his present compression ratio. I was pulling 14" with a 218 @ .050 on a 360 with a 10.2:1 CR.
 
ramcharger said:
I agree about the headers, I just don't know enough about the TQ's to comment. I hope I didn't come off like a butthead Rob, that's not my intention. :)
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Like a butt head? Not IMO! Opinions are good and as this delevlops into a tech session, it gets better.

On the Dodge trick engines being different, well, yes, but it is still an engine that suffers from all the pit falls of an internal combustion engine.

The real important thing here is the cam being looked at here is not to big to run a high comp. ratio engine well and octane could be an issue as well as air. Between you and I, there several thousand feet difference and it shows in the replies we give. Not paying attention to where he lives is a fault of mine, but I still stand by what I wrote. The half point of compresion - upwards- could be used if octane is there to prevent pining.

I'l not argue that it is possible to run a 10-1 iron head engine on pump gas, but combo dependent, it's ethier a ping fest or a retarding the timing issue that kills the power.

He'll find another .5 in a few thousand miles when carbon builds up.
 
I'm running 11.2 cr with j's, on 93. if its a weekend car with a trip a few times to the track go with as much cr as you can. i run about 205 cranking psi. set the timing at 32 total and its fine for crusing if your going to race it mix a little race gas and bump timing up to 35. If you talk to the guys in your area with very fast sb's be it mopar ford or chevy, you will find most are up their in CR. PM me if you want spacifics if you decide to run on the edge (if you dare)

demon burnout.jpg
 
Thanks again guys for the input:) I appreciate all the comments as I haven't put a wrench on a LA small block for over 20 years:angry7:
The comp cams is what I'll be using so I'll need to work around it for the rest of the build.
As far as the compression ratio goes, It will be increased.
After looking at other posts about headers and Hi-Po manifolds, I've decided to go against everything I believe in and put a set of headers on it too](*,):angry3:
Now I am gonna have to ask the million dollar question that has been beaten to death already.....Dougs or TTI's:dontknow: As it is I am going to nix the power brakes,but this is my wifes car and the power steering has to stay.
On top of it, I have read in other posts that I am going to have issues with the Z bar, which is why I vowed never again to have an A body with headers......but a 30 HP gain:-k I think I'll suck it up:toothy10:
My buddys Robzilla and Darn Dart both race in Minot ND,which is pretty much the same elevation as here,so I'll check with them what CR and tuning they do on their cars.
Feel free to chime in on this build....... Our dollar is getting stronger so the piggy bank is soon to get smashed. This car will be on the road next spring.
IT'S GO TIME :burnout:
 
My 68 Dart GTS 340 4speed has a set of Hooker Headers on it and it isn't bad. A little tight where you adjust the clutch rod, but other than that not bad. I have power steering. Don't know maybe you can't even get Hookers any more. Just my 2cents worth.
 
Buy Dougs and use the $200 you saved on an exhaust system or something else you need.
 
I really liked my hooker supercomps for my A body, so well, in fact, I have a ceramic set built in 98 still hanging around.......... Been a long time since I sold my Duster. I had a set of non coated supercomps on it.

I too, think you will be just fine with your power brakes, maybe tune in your idle timing for max vacuum, and them set your dist for the proper full? (Shorten mech advance, ect) 12-18BTDC is where I like my hotter cammed engines to run. I still bet with the good ol 12 idle 36 total, that cam, at 1000rpm your brakes will be just fine.
 
rumblefish360 said:
Like a butt head? Not IMO! Opinions are good and as this delevlops into a tech session, it gets better.

Thank you Rob for not taking my post the wrong way. :)

On the Dodge trick engines being different, well, yes, but it is still an engine that suffers from all the pit falls of an internal combustion engine.

Have you seen the new block and heads they just came out with for NASCAR? Wicked trick! Supposedly they will be offered for sale to the public, but I can't imagine at what price, lol.

The real important thing here is the cam being looked at here is not to big to run a high comp. ratio engine well and octane could be an issue as well as air. Between you and I, there several thousand feet difference and it shows in the replies we give. Not paying attention to where he lives is a fault of mine, but I still stand by what I wrote. The half point of compresion - upwards- could be used if octane is there to prevent pining.

It's possible and has a lot to do with how the engine is built. Special coatings, chamber shape, knocking down sharp edges on the pistons and chamber, the pistons used, quench, altitude, etc will all have an effect on how much compression one can run with a given cam. Even an engine built by two different people using the same parts will have differing octane/timing requirements depending on the machine work and care taken in the assembly.

I'l not argue that it is possible to run a 10-1 iron head engine on pump gas, but combo dependent, it's ethier a ping fest or a retarding the timing issue that kills the power.

He'll find another .5 in a few thousand miles when carbon builds up.
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Like EL5DEMON340, I like to push the envelope. I can usually get away with it as it's not my first time around the block and if I screw up, I blame no one but myself and chalk it up to a learning experience, lol. Not everyone can though and you have a point about the availability of fuel. The best we can get here is 91 octane. I know I'm on the edge as I had put 5 gal of "no-name 91" in my truck and I knew I had a problem. I went back to the local Phillips 66 and diluted it with 10 gal of 91 and I was good to go. I also have a switch on my dash for my Mallory ignition box that pulls out a pre-determined amount of timing that I presently have set for 4 degrees for just such situations.

I most certainly would not recommend running 10:1 or higher on an open chamber iron head LA engine with a cam under 224 duration at sea level to the average builder. It can be done with a Magnum head if quench is set to .045" or less.

Just for fun, it would be interesting to have one of those 0-60 computers in my truck and run it with crap gas and 4 out, then run good gas with the 4 back in and see the times.

I regards to carbon build up, did you ever use a can of BG44? I ran a can of that in my 4Runner tank before I pulled the head off and you could see the carbon coming off in big flakes. Good stuff. :)
 
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