What Cam and other questions...512 Stroker RB Block

[splicer]

Forgot to mention I'm running the 88cc Eddy heads and flat top Mahle pistons.....CR is 10.7 to 1 and I run pump gas....84cc with flat tops and 512 ci might give you too much CR

Splicer

 

[Propwash]

Guys... I have a renown respect to the amount of knowledge you bring to this site and appreciate all the time you've taken to explain the dynamic's and how they work together. I also appreciate you sharing you past experiences and resources. Truly an impressive group of folks here.

Taking into effect all of your great information, advise, tips and tricks I armed myself and made some phone calls. Talked with Dave at Hughes, Chris at Comp Cams and Andy at 440 Source. These guys were all top notch when it came to support. Took the time to discuss all aspects of this build, including what has been discussed on this thread (BTW...they all knew about For B-Bodies Only..word must be getting out) Anyways...Andy at 440 source was great. We talked about flat top vs. Dish and like Meep mentioned, their Dish pistons have a large quench area designed into the pistons. We talked comp ratio, the heads and the bore/stroke combinations. He recommended:

.030 Bore with a 4.250 stroke
-17 Dish that will be -.015 Deck height. Valve reliefs are good to about a .700 lift
Use the 84CC Closed Chamber Eddy's (for better quench) getting me right at 10:1 Comp

One thing I didn't get a chance to discuss too much is quench being there was a lot of other variables/parts for the motor to discuss as well as costs. So, given the engine specifics above, what should I do with the deck the maximize quench? Motor is ready for deck plate if need be, but guy at the machine shop says she is straight as an arrow across the deck. Would a .039 head gasket and leaving the deck where it is get me the maximized quench?

Like earlier mentioned, I will be going with a Mechanical flat tappet cam along with 1.5 adjustable rockers. Again Dave at Hughes and Chris and Comp Cams were great. Real in depth and asked a ton of questions all about the internals as well as the car specifics outside the engine bay. I'm gonna post the Cam cards for the cams they recommended. 2 from Hughes and 1 from Comp. Could you please tell me what you guys think of these three cams if you could spare a minute or two? Again, I very much appreciate it.

Here's the Comp Cam:
Brand:COMP Cams
Manufacturer's Part Number:23-232-4
Part Type:Camshafts
Product Line:COMP Cams Xtreme Energy Camshafts
Summit Racing Part Number:CCA-23-232-4

UPC:036584080206
Cam Style:Mechanical flat tappet
Basic Operating RPM Range:2,500-6,500
Intake Duration at 050 inch Lift:244
Exhaust Duration at 050 inch Lift:252
Duration at 050 inch Lift:244 int./252 exh.
Advertised Intake Duration:282
Advertised Exhaust Duration:292
Advertised Duration:282 int./290 exh.
Intake Valve Lift with Factory Rocker Arm Ratio:0.520 in.
Exhaust Valve Lift with Factory Rocker Arm Ratio:0.540 in.
Valve Lift with Factory Rocker Arm Ratio:0.520 int./0.540 exh.
Lobe Separation (degrees):110
Camshaft Gear Attachment:3-bolt
Intake Valve Lash:0.016 in.
Exhaust Valve Lash:0.018 in.
Computer-Controlled Compatible:No
Grind Number:XS282S
Valve Springs Required:Yes
Camshaft Manufacturers Description:Very strong mid and upper rpm power. 10:1 compression with 3000+ stall.
Quantity:Sold individually.
Notes:3-bolt style. For use with 1.5 ratio rockers.

- - - Updated - - -

Hughes #1

Flat Tappet Solid / One Bolt Timing Gear. Hot street/bracket racing. Large dual plane or small single plane intake manifold. 1 7/8" Big Block and 1 ¾" Small Block primary tube headers. 3.91:1 minimum rear gear ratio. 3600 rpm stall speed. HP ported Stage I or II cylinder heads. 180psi suggested cylinder pressure.

Camshaft Technical Details
Intake Valve Lift 1.5 .572
Exhaust Valve Lift 1.5 .579


Intake Valve Lift 1.6 .610
Exhaust Valve Lift 1.6 .614


Intake Duration at .050" 252*
Exhaust Duration at .050" 256*


Lobe Separation Angle 108

Intake Opening at .050" 21° BTC
Exhaust Opening at .050" 59° BBC


Intake Closing at .050" 51° ABC
Exhaust Closing at .050" 17° ATC


Min. Suggested Cylinder PSI 175

Sweet Spot RPM 2800 - 6600
Note: The HTL series of camshafts give the maximum performance available with a flat tappet camshaft and .904" diameter lifter. When used with 1.6:1 ratio rockers they will achieve lift rates and performance of a roller tappet camshaft. Also similar to a roller camshaft, the HTL cams give very wide, flat power curves, but piston to valve clearances must be checked closely.
Caution: Minimum piston-to-valve clearance is .060" intake and .100" exhaust. If your clearance is not adequate, we have tooling to cut deeper valve reliefs.
Check our tooling section or call us.


Maximum lift with stock guide height is 0.450", more lift requires shortening the valve guides.

- - - Updated - - -

Hughes #2

Flat Tappet Solid / Three Bolt Timing Gear. Street/strip. High rise dual plane or small single plane intake, headers, minimum 4.10:1 rear gears. 3400rpm stall. HP ported Stage I cylinder heads. 170psi suggested cylinder pressure.

Camshaft Technical Details
Intake Valve Lift 1.5 .563"
Exhaust Valve Lift 1.5 .572"


Intake Valve Lift 1.6 .600"
Exhaust Valve Lift 1.6 .610"


Intake Duration at .050" 248°
Exhaust Duration at .050" 252°


Lobe Separation Angle 108

Intake Opening at .050" 19° BTC
Exhaust Opening at .050" 57° BBC


Intake Closing at .050" 49° ABC
Exhaust Closing at .050" 15° ATC


Min. Suggested Cylinder PSI 165

Sweet Spot RPM 2400-6400
Note: The HTL series of camshafts give the maximum performance available with a flat tappet camshaft and .904" diameter lifter. When used with 1.6:1 ratio rockers they will achieve lift rates and performance of a roller tappet camshaft. Also similar to a roller camshaft, the HTL cams give very wide, flat power curves, but piston to valve clearances must be checked closely.
Caution: Minimum piston-to-valve clearance is .060" intake and .100" exhaust. If your clearance is not adequate, we have tooling to cut deeper valve reliefs.
Check our tooling section or call us.


Maximum lift with stock guide height is 0.450", more lift requires shortening the valve guides.

 

[RustyRatRod]

I kinda thought Dave would go flat tappet. The reason for that is because using their components, you will rival a roller in power at half the cost. Their lifters are really light.

Now, about your quench question. In "MY" opinion, the best and easiest way to acheive quench is to zero deck height the block in relation to the piston at TDC. Once that is done, then the head gasket thickness itself IS the quench. Simple, huh? I don't think you will need quench with your combo to run on pump gas, but 1) it will not hurt because it will make more power and 2) it will make more power. ;)

EDIT:

I don't know. I went back and looked at all of the .050 duration figures with each recommendation. I do think you might be in trouble with no quench. Those are short duration figures, which will result in pretty high cylinder pressure and even with aluminum heads with no quench, you'd probably spark knock. I think those are good recommendations. All of them. Long as you zero deck height and use the head gasket as the quench distance (around .035" is best) it'll skreeem.

 

[Meep-Meep]

10:1 compression with 175-ish PSI seems reasonable. They say aluminum heads - all things being equal in terms of CR and PSI - will help the detonation issue, but some say it doesn't make a hill of beans worth a difference. I would still keep the CR to no more than 10:1 or even 9.5 for a true pump gas motor. My personal thought is to take advantage of the 512 inch and go 9.5:1 max because you can afford it.

Quench is a good thing but must be employed properly. I think there is a balance that provides proper swirl in the chamber but also allows the flame to get in and burn ALL the fuel vapor in the chamber from one end to the other. The flame can't get into very tight places, like the area of the piston above the top ring, or a shrouded part of the chamber. Too tight of a gap between the head and piston along with big domes may very well result in an incomplete burn and reduced power with higher emissions. It also will tend to require more total advance to get the job done. A fast burning chamber is an efficient and happy chamber. So run the .040" gasket and if your piston comes out to zero to -.020" I think you will be just fine. And the dish will hopefully be a mirror image of the chamber or close to it.

The cams all seem to be optimum for a 440, NOT a 512. You are getting LS numbers in the 108 and 110 range and I don't think you need that. Yes, the 512 will soak up some camshaft but what about 112 to 114 deg? Again, this is a 512 kyoob motor and you don't have to worry about making more torque. I think a lift in the .530" range with 1.5 ratio is about as much as you should go to maintain a smooth acceleration and deceleration curve and keep the the valve train happy for 50 K miles. And with a lower RPM ceiling, say 5000, you can probably run less spring than if you were going to 6000 RPM. You want enough spring to keep the lifter in contact with the cam lobe at all times and I'm sure the big cam companies have that number figured out. This is very important by the way. I believe spring pressure is a balance of RPM limit and oil film strength between the lobe and lifter. Sure, you can run the more aggressive cam and make more power but I see it at the expense of reliability and vacuum. Are you running a carb? Then you WANT a strong vacuum signal. My recommendations are also based on heavy use, but if you only put 2000 miles per year then you can go crazy with the build and make it last for many years. My personal experience is based on 90 K miles of seat time in 9 yrs in a 68 Mustang and 35 K miles over about 3 yrs on a 72 Porsche 911. Most people who build the "killer street cars" will never have to put brakes on them twice.

 

[RustyRatRod]

I did think the duration was short.....but any of them would be great street cams.

 

[Propwash]

Thanks guys....Sounds like I'll be just in their as far as the deck vs. piston level. Unless the machine shop has a change of heart about the deck being arrow straight I may leave it alone. As far as the cam, I'm gonna call Dave back on Monday to discuss more options and possibly Comp regarding custom grinds.

Feeling pretty good about all the great feedback and the specific's are really starting to be etched in stone. Update on the motor is the ARP studs are installed for the mains and line hone should be done by early next week. 440 Source rotating assembly should be showing up next week along with some other goodies.

As far as the ignition......I'm planning on running the MSD Digital 6AL, and a Petronix Flamethrower coil. Guys have any good recommendations on a decent Vacuum advance distributor? I can get the MSD Digital 6AL on trade for welding in some floor pans, but I haven't heard anything good/bad about the Digital 6AL.....any feedback on that or the ignition route i'm headed?

 

[charger360]

i think the build looks to be going in a really good direction. one thing i have found with vendors is they want to sell you things that make you say wow! by that i mean it really works and you will rave about the power. but the car will be mostly street right? how much milage do you expect out of this engine 20k 50k 80k? it is a big engine lots of cubes you are running a stout gear some converter, the reality of running on the street is somtimes you have to put fuel in that is not a known quality if you compression ratio is on the ragged edge and you get poor fuel on a road trip even taking some timming out of it may not get you home safe. i say that because it happened to me once. a really big cam will wear the springs down after a while on a strip engine thats no big deal as you freshen often but on the street thats a pain! same with the lsa more angle 112 -114 is smother and has better street manners, you may not need it but it is worth looking into before making a purchase you really need to make sure the vendors understand what you are looking for and make sure they don't turn your engine into a showcase for a product they sell. i am not saying that is their intent but they are engine people and somtime they see things in an ideal light. sorry for the rambling response.

 

[RustyRatRod]

Well, one thing is this. I would tend to go with one of their recommendations.....I would weigh heavily on Dave's advice, since they DO build engines also, whereas the others just sell stuff. The reason I say go with one of their recommendations is simply because YOU are telling them what YOU want out of the engine combo and car. Obviously, from the duration @ .050 numbers you posted that they suggested, you're telling them street car......and those are great grinds for just that. I cain't and won't argue there. But, make SURE street car is what you want. Because what they are assuming is you want docile idle, great vacuum signal with probably no canister involved. Nothing wrong with that either......it's just that I think most people would want to take more advantage of 512 cubes since they would be buildin the thing. I know I would. I mean with the right head, intake cam combo you could eclipse 700 HP without too much trouble. 700 HP. 700 HP. 700 HP. Look at that for a few minutes. lol

 

[Propwash]

Thanks Charger360...Good advice. I'm finding out that building a hybrid (street/strip) sure leaves a guy with a pretty small envelope when in comes to putting it all together. I think next go around will be either one or the other. As far as the engine/car, it will not be a daily driver, but more of a weekend warrior. I wouldn't expect more than a few thousand miles a summer.

Thanks RustyRatRod...Dave is a pretty bright guy. I could tell instantly when he asked about 30 questions right off the bat before we could start dialing in a cam that would suite for my driving characteristics. He mentioned a Vacuum canister may be needed, but honestly that's no big deal if it rolls out that way. Biggest thing is I want the most bang for my buck when it comes to the cam and I don't end up with some generic grind that sits in the guts of half the more throaty cars out there. Comp was pretty decent and dialed in the combination pretty quickly, but I also got the feeling that is was more of one of the streamlined cams out there. Meaning the cam was made to meet the market, but not really made to suite MY engine. For obvious reasons of course. A couple of the big things holding me back on fully unleashing the 512's fullest extent of power is 1) Budget.......A nice set of ported Victor's or Indy's would be nice, but once said and done you know as well as I that's into the several thousands with head work and valvetrain alone. Wish I could, but unfortunately I have to live in reality when it comes to how much I can spend. 2) would be drivabilty..like I mentioned before trying to find that perfect balance for street/strip is well....freakin impossible. Seems like any combination starts working its way one way or another...I've driven/ridin in 400-500Hp cars and 700-800HP cars. There also seems to be a balance there..Cross a threshold and the car becomes just too stout for normal enjoyable street driving. Not that you can't, but a lot more effort needs to be taken to keep the monster under the hood from turning you into a tornado on a roller skate vs. just being able to enjoy the ride. Seems to me i'm trying to find a happy medium in between the two. That many cubes, I don't want to cut the motor short of its potential, but on the other hand I don't want to create something outside of the box of what the cars going to be driven for a majority of the time. I will admit...700HP looks pretty damn tempting.

 

[RustyRatRod]

Are the Edeldbork heads in your budget as cast? If so, this is who we use around the middle Georgia area for port work. http://killiansportingservice.com/ He's pretty renowned. He will fully port and flow them for probably less than 700. He also has access to a full machine shop and they can retouch the valve job and set you up with whatever spring you need. Just a thought. It would certainly be better than "thousands", I can assure you.

 

[charger360]

that is a really good price for that kind of headwork! you could buy the heads get the work and set up done for a about 2500? a lot of guy's charge about half that just for the port and set up work. and even that can be a deal somtimes.

 

[Propwash]

I hear ya...Around here pickins are pretty slim when it comes to getting any kind of serious head work done and the folks that do, know they are few and far between. That is really cheap and I appreciate the tip RRR.... I'm heading over to B & B Racing engines a bit down the road from me tomorrow, see what they have to offer and do some comparative pricing for head work.

 

[Propwash]

Alright fella's, nuther question...

As far as Duration and lift; exponentially which makes more power and where? Here's some spec's on the two cams i'm down to.

Cam1
Duration at 050 inch Lift:244 int./252 exh.
Advertised Duration:282 int./290 exh.
Valve Lift with Factory Rocker Arm Ratio:0.520 int./0.540 exh.
Lobe Separation (degrees):110

Cam2
Duration at 050 inch Lift:243 int./251 exh.
Advertised Duration:272 int./280 exh.
Valve Lift with Factory Rocker Arm Ratio:0.546 int./0.566 exh.
Lobe Separation (degrees):110

Thanks

 

[RustyRatRod]

Damn they are real close. I don't think you'll ever feel a difference, but I say go with the more lift. They still seem a little small for a 512. Are they hydraulic roller grinds? If so then they are really small for a 512. One thing about it, they'll set your eyeballs back in your head off the line.


I keep forgetting about hydraulic rollers.....they'll fool you. I kinda compare everything to solids and you caint do that with a hydraulic roller. Those will probably be pretty good.....but I would still use the one with more lift.

 

[Propwash]

These are solid flat tappet RRR...

 

[RustyRatRod]

These are solid flat tappet RRR...

Ok, then IMHO they are too small for what you're doing. Even for a street car. 512, 512, 512, 512

I would run something like this at the very LEAST.

http://www.lunatipower.com/Product.aspx?id=2561&gid=317

Oh and one more thAng. It wouldn't hurt to have Lunasty grind that up thar on a 112 LSA. Bigger motors usually respond real good to to a wider LSA. I'm sure Lunati would do it for minimal if no cost.

 

[Propwash]

I like the Hughes cams as well, but Dave is saying a Vacuum canister or a electric pump is a must, I need their valve springs, locks retainers (which require machining the heads for positive seat)....Might be a sales pitch. Doesn't matter if I go with Crane, Comp, Hughes, Lunati, Mopar, all the cams in those durations/lifts all have an end description of 3000 or higher stall, 3.91 and up, stage II or III porting, 10:1 Comp and up. Go any higher and they're at 4.30's and up, 4000 stall and up, 11:1+. I know the 512 is going to eat up some of the duration, but how far out can a guy go from these two cams before the car crosses that line from street/strip to just Drag? Screw it, next time i'm just building a drag car...LOL

 

[RustyRatRod]

Dave is right. I'm sure he said seaL instead of seat. The guides require machining because of the inner sprAng diameter. If you look at that Lunasty I recommended, you'll notice the duration is real close to the two you posted, but it has more lift. Also, I really think the 512 will see great benefit from the 112 LSA. All jmo, any of them will work close.

 

[Propwash]

Heck man...this cam dilemma is tough cookie to cut. Picking out the paint/wheels was 10 times easier. I guess this when it comes down to it, this is the real meat and potato's. And you're right, "Seals"...my bad

 

[RustyRatRod]

Well look, Harold Brookshire has probably forgotten more about cams than anybody on earth knows. He ground for Ultradyne. WAY back, he ground for General Kenetics. They had some kickass grinds then. Harold has been responsible for probably 90% of breakthroughs in cam technology in the past 30 plus years. Now he's grindin for Lunati. It's always been kinda a runnin joke with us around here "just put a Harold cam in it". And really, it's no joke. Them Voodoo grinds are about the top of the line right now. You just caint go wrong. Harold is DA MAN.