My bud with the 502 is trying to decide on a cam, trouble is his 502 was a marine motor that had a blower on it and will only be at 9.1 comp. He is going to have an accel dfi fuely set up on it and they say it will really tame a cam down. he wants a real rumity sound and lots of power. I suggested something in the 240/250@.05 range but now am wondering with his lower compresion than I originally thought if that is going to be a good comb, any ideas or questions on the set ask away. O it has regtangle port heads, not sure on which they are. This is a street car with a 4 speed and 3.73 gears, in a 69 camaro.

no opinions on whether this cam is too big? don't want him to have a reall blubbery bottom end, or will the fuelie set up allow him to run a big cam with 9.1 compression. could really use some help with this.

Rumpety comes with overlap, which is related to narrow lobe separations. ie; less than 110 deg. The EFI is not going to like this, but it can be accomplished. It would be easier to widen it up to 112 or 114.

You didn't give us any other details for the guys car, or even if you are talking about a solid or hydraulic. For a race cam it's tame, for a cruising cam it's the wrong choice.

it is a street driver with 3.73 gears and a 4 speed. Its newer mark series motor with a hydrolic roller, which he is staying with. Its going in a 69 camaro. The car will have headers and 3 inch exhaust, the dfi accel is supposed to support 550 hp, which he wants to be at, is it possible?

Running the numbers for the 502 on every calculator that I have seen, the 502 motors do not have the advertised CR unless the block is decked for near "0" piston/deck. If I were him, I would get some real measurements on piston/deck and CC the heads, then he will know for sure what he has for CR. If the intake is off, it's only a head gasket and a couple of hours work, to me it's worth the time and trouble.

That is being done as we type, guy has the heads off and before he cuts the heads its only a 8.75 to one motor, it had a blower on it in the boat. He knows to get more than 9.1 he needs a set of pistons.

Originally posted by orange2:
it is a street driver with 3.73 gears and a 4 speed. Its newer mark series motor with a hydrolic roller, which he is staying with. Its going in a 69 camaro. The car will have headers and 3 inch exhaust, the dfi accel is supposed to support 550 hp, which he wants to be at, is it possible? The commander 950 will support whatever HP you want, you just have to size the injectors appropriately. For 550HP you would likely use 42lb units. Doug F is the master of these units, and he posts here and on Chevy Talk.

For the cam I would go with a Crane HR-226/345-2S-12 IG ;
FAIR IDLE, MODERATE PERFORMANCE USAGE, GOOD MID-RANGE TORQUE AND HP, MILD BRACKET RACING, AUTO TRANS W/2500+ CONVERTER, MILD MARINE PERF., 3000-3400 CRUISE RPM, 9.5 TO 11.0 COMP. RATIO ADV. BASIC RPM 2500-6000

Should pull your target numbers easy with those heads.

Thanks tjc, this is a friends car. He has talked to a guy in florida who has some experience with the accel setup and I believe those are the injectors they are going to use. No offense, but any other suggestions besides a Crane? Lunati, or crower or isky.

Lunati; 54849LUN, 232/242, 578/595

Isky doesn't have their specs online yet for the GEN VI.

Crower; 01404LM, 236/245, 586/612

These would all work well, and produce tons of torque down low.

how about the lunati 54869? 293/303 234/244@.05 629-612 lift on a 114 lsa or is this just too big? Sorry to be so picky, but he really want to do it right the first time. If the cam seems to big on the dyno he said the dyno guy would buy it from him so he kind of has a freebie on going to big to start with.

Although similar,
The 54869 closes the intake at 49ABDC
The 54849 at 46ABDC.

So the latter will produce a little more cyl pressure. I think this is important because of your compression and gear multiplication.
It will still give a good lope.

Where is Harold when you need him????

I appreciate your help, was also hoping harold would be on tonite. I see the lsa on the 849 is 112 and the 869 is 114, would that make up for the lost pressure? He wants the biggest he can run cause he pulled out a pretty well built solid roller 454 and he doesn't want it to be a dog. He got this 502 bought right and got his 454 sold for good money so he decided to make the switch. He isn't much of a gear head guy, that is why I am trying to help get some info for him. His builder is recommending a cam similiar to what you said, but the guy who is familiar with the accel dfi set up said it will really tame the cam down at idle and he wants it to lope. So he wants ot error on the side of big, and if it runs to blubbery on the dyno he can change it, he just doesn't want to start to small. Hope all that makes some sense.

The EFI will really smooth out the idle, i agree.
There's a local here with an Accel Ramjet system on a 502, and it idles around like a stocker. But it is a seriously fast little car ( vega ) .

The low compression is also fighting you a little, because it wont give that real ragged sound you get with a bigger cam. It will just sound dull. Presumably you can get any of these guys to grind it with as narrow a spread as you want, but I don't think you should delay the intake closing point any farther.

So you think he should really stay with nothin bigger than the 849? I told him when he got the dam thing that since it had a blower it could be real low comp, but he said it was around 9.5 to 1, well it isn't. I agree about the idle, it takes some comp. to give you a nice crisp lope. I better have his builder just call lunati and talk to steve or harold, I don't want to have him be unhappy. I will pass this info on to him, and I really appreciate the cam lesson.

He could change the heads I have same 502 marine with cast iron Sq ports 119cc chambers 8.75 comp.. Was going to run the old closed chamber SQ ports would bump compression to 9.9 or the edelbrock(also GM) aluminum at 110cc would make 9.6 comp. something to think about.

Originally posted by orange2:
So you think he should really stay with nothin bigger than the 849? I told him when he got the dam thing that since it had a blower it could be real low comp, but he said it was around 9.5 to 1, well it isn't. I agree about the idle, it takes some comp. to give you a nice crisp lope. I better have his builder just call lunati and talk to steve or harold, I don't want to have him be unhappy. I will pass this info on to him, and I really appreciate the cam lesson. Well, here's the crux with a hydro roller; They wont spin past 6K to let a bigger cam come into it's own. So if you over cam it, not only does it kill the bottem end, but it will never become efficient before it runs out of rpm. So it's a dog at both ends of the spectrum.
They are ideal for a street car, cause they make tons of torque, and that really is what you should be shooting for. Otherwise it will dissapoint you. ( and make you look silly at the track )

I don't think he wants to spend anymore money on it, the dfi was 3300 alone. His engine guy told him he could do pistons for around $800, he doesn't want to do that so I would say heads would be out also. How does yours run and what is your set up?

Tjc, I hear what you are saying and I will pass on the info. He is going to run the beehive springs to help that out. I just figured he should get some topend power cause a 502 will have enuff low end anyway. I have learned though without much comp his choices are narroer than I thought they would be. I just thought with a 502 having that many cubes he could go quite big on the cam.

Imho, I bet a good old CC 282S solid cam will do nicely..

The low compressioned 502 motor will probably make right at 550hp and darn near 600t and be really streetable..

Sounds like a real winner to me AND no roller cam hassles at ALL....

pdq67

To my knowledge he does not want to change, he wants no hassle power. Turn the key and go type guy. I guess since he has the hydro roller now going to a solid in his case is a step backwards, this guy just want s to get in and go. Any ticking noise will drive him crazy, he is very particular, too say the least.

Need to keep the lift in check to use the stock rollers. .550 - .570, depending on how the cam is made. Comp makes 2 standard grinds that I bet would work well.

XM284HR 284/290, 230/236, .547/.547 on 112LSA, install at 110ICL

or the cam I am running now

NX279HR 279/294, 230/242, .537/.541 on 113LSA, install at 108ICL.

I know they make the XM284 on a GENVI core as a standard item, you will have to check on the NX279HR, but I think it is also a standard manufactured item.

Sorry I haven't been around, but I lost my monitor(It was 10 years old....) and can't afford another one until payday. I can sometimes reply from work, as I'm doing now.....
I would use a Lunati 50299 custom-grind BBC hydraulic roller. The grind number is 02-HR14-HR15-12(or 14...)-A01. This cam is 284/292 at the seat, 230/238 at .050, and .600"/.600" valve lift. I ran a 4° bigger cam in a 9.2:1 CR 540, with the cam ground on 114 LSA. We had the following results:
RPM Torque BHP
1500 504 144
2000 519 198
2500 514 245
3000 551 315
3500 583 389
4000 599 456
4500 625 536
5000 625 595
5250 517 617
5400 613 630
5500 594 622
This was with a 830cfm Holley carb, 32° total timing.
This was on Earhart Engineerings dyno, fall 2001.
The engine owner had TWO of these engines in a boat......
Notice that the engine varied 121 ftlbs of torque from 1500 to 5500, and only 31 ftlbs from 4000 to 5500....
Its' little brother would do a 502 JUST FINE!

UDHarold

GRN69,

Have had a chance to run yours more? You're running a 468 right?

thank you so very much to all that repied, sorry about your monitor harold, and I really appreciate your response.

No sir, just a little ole 408 [that will throw this car sideways without even thinking about it]. Shelved anything bigger until later on. Kinda figured there's no sense upping the HP and torque until I get some chassis tuning done. Have everything to do the bigger motor except a set of rods and some misc. bolts. Beside that, I am now sidetracked on a strip/paint that should be complete by late April early May - at least that is the plan.

i dont know i have a hyd roller special grind in my 540 in my 69 camaro and it pulls way hard into the 7250 range no problems you can feel it fall off at about 7400 really quick

Holysh t, how do you get it to do that motown?

Yes, what's the spec's on THAT hy-roller cam AND what kind of kit are you using to get it to rpm THAT high???

pdq67

its a special grind i thought up and ordered from comp 647 647 112 lobe sep 258 264 at 50 i guess its my gears and huge heads its in a 540 with 345 pro 1 heads 38-4200 stahl on a dyno it might quit sooner but the thing dosent start to nose over tlii 7400 and goes completly flat so i keep shift points at 6,800 to 7,000. also 410 gears as for kit just the basic spider roller lifter kit with a turn and a quarter on preload

are you sure your tach is accurate, no not trying to be a smartazz, its just 1000 rpm higher than most seem to get.

Originally posted by motown/malibu:
its a special grind i thought up and ordered from comp 647 647 112 lobe sep 258 264 at 50 i guess its my gears and huge heads its in a 540 with 345 pro 1 heads 38-4200 stahl on a dyno it might quit sooner but the thing dosent start to nose over tlii 7400 and goes completly flat so i keep shift points at 6,800 to 7,000. also 410 gears as for kit just the basic spider roller lifter kit with a turn and a quarter on preload =
Hmmm :rolleyes:

No problems here with hyd rollers.
They rev past 6000 rpm easy.
Even with 2.25" valves rpms have been 6400-6500 at the end @ 130+ mph
Comp rollers, Ultradyne cam`s

big red, agree, but he is claiming 7400 before it completely noses over and shifting at around 7000. He has much better headds than I, but I only have a 454 with a larger cam than he is running and mine starts to fall off at 6800. Also, do you want to spin a 540 that high? Have no experience with one just curious.

i gurantee its correct and ill takeanyone for a ridwe it pulls to 7250 and goes flat at 7400 like i said it may not make power to 7250 on a dyno but i know when i feel a powerband nose over . hell i had a comp nitrious hp cam in a 383 with a 671 488 501 and it spun to 7500 all day quit at 7650.. it may quit at 6100 on a dyno and in my car as well but youwouldnt know the diffrence in the seat of your pants
andyes wolf its a special grtind 01000-8cbvi3373/3374 serial# a 2225 2003232 me and don at motor machine in fairoaks calif thought it up one day .. incase tyou want to check further

well had a 630 630 isky solid flat in a 468 that i spun into the 9grand range on more than one occasion its all in how well the motor is built. i have a friend that runs a 579 into the 9500 range in a pro stock nova .. imo its a myth to keep a big block at 5500 to 6000 unless you have stock parts .. you csan see the innards of my 540 at my website its all there and i should mention my 468 had a gm crank. some would say im insane but i have never cooked a big block spinning it up into no mans land. if ur in the folsom area ona wed nite drop by the red robbin im mostly there ill take you for a ride first show starts april 13th .

I can see a pro stocker needing to spin that high but why would you with a street car? 9000 out of a 468 with 630 lift? Say what you want but that thing wouldn't be making any power, I do see how it could be. If something quits making power ona dyno at 6100 why the hell rev it so high.

the 468 went into the 9 grand range once because of stupid is as stupid does doing a burnout over a hill hitting a man hole cover that was unseen at the exact moment i hit second gear with no seat belt on and full race slicks the car went sideways very vioently throwing me sideways into the passenger seat wedging my elbow inbetween my leg and the steering wheel it was screaming loudly when i was able to get it back under control and killed the motor i hit the tell tale button and it read back 9100 . the second time was when it hit some water and the throttle stuck wide open .. as for thwe 540 i quit and shift when it quits pulling .

my 427 small block has an isky roller hyd in it and it spins to 7.500 strongly rr282/294 imo its a myth that hyd cams wont spin ..

Originally posted by motown/malibu:
the 468 went into the 9 grand range once because of stupid is as stupid does doing a burnout over a hill hitting a man hole cover that was unseen at the exact moment i hit second gear with no seat belt on and full race slicks the car went sideways very vioently throwing me sideways into the passenger seat wedging my elbow inbetween my leg and the steering wheel it was screaming loudly when i was able to get it back under control and killed the motor i hit the tell tale button and it read back 9100 . the second time was when it hit some water and the throttle stuck wide open .. as for thwe 540 i quit and shift when it quits pulling . You know it!!! hey Joe Dirt... what ever happened to that HEMI anyway??? :rolleyes:
graemlins/beers.gif

Ok so it was an accident, thought you meant you did it regularly. Sorry thought it might have been a missed gear or something. I can see a small block 427 spinnin to 7500 with a hydro, valve train is much lighter. I get real nervous when my 454 gets past 6500.

boy you post some facts and it doe sbring out a certin class of incipid and shallow people . here is a loop for you . take 10 diffrent machine shops give them all the same parts for a 496 and you will be lucky if to make the same numbers ... dont know 68 tuna boat never had a hemi

Originally posted by motown/malibu:
i gurantee its correct and ill takeanyone for a ridwe it pulls to 7250 and goes flat at 7400 like i said it may not make power to 7250 on a dyno but i know when i feel a powerband nose over . hell i had a comp nitrious hp cam in a 383 with a 671 488 501 and it spun to 7500 all day quit at 7650.. it may quit at 6100 on a dyno and in my car as well but youwouldnt know the diffrence in the seat of your pants
andyes wolf its a special grtind 01000-8cbvi3373/3374 serial# a 2225 2003232 me and don at motor machine in fairoaks calif thought it up one day .. incase tyou want to check further =
I wasn't doubting it was a custom cam, I use customs all the time.
I also have no problem with RPM in a properly built Rat, I have built a few over the last 30+ years.
The last one I actually owned was a 482 probably before you knew what a car was & it was regularly shifted at 8500+.
Difference was it had a solid roller not a hyd.

The part of your deal I have a problem with is 7400 with a hyd roller & makin power to "7250",, but hey,, if it pulls to "7250" more power to you & your builder. ;)

i wasnt chewing at you mike . please forgive if it seemed i was . hey iknow on a dyno it proably wont make power past 6+k but ifits still moving forwardand continuingto pickup moment thenitsstill pulling right ?

Just to throw in a couple of things here tht I think may back his claim to the 7K+ rpm on a hyd roller. He may be onto something. I had a conversation with Crane when I was looking at my cam. Only reason I did not go with Crane was the long seat timing in there cams and the lower compression (9.5-9.6 in my 408 motor). But the tech I spoke with had very good info. What I got from him and based on what we already know we can see a pattern.

The way to make the hyd roller rev is:

Billet Core = tolerance of high springs pressures on the equivalent level of a solid roller cam.
1-1/4 turn from "0" lash preload literally eliminates the lifter plunger travel. If the springs are heavy enough, along with the correct pushrods to prevent flex in the valvetrain, you could in theory overpower the hydraulic mechanism built into the lifter and essentially run the lifter with the plunger bottumed out.

Doing so on a standard hyd roller core would spell disaster within a couple of miles. But I think what he is doing is setting it up like a solid roller. I would guess spring pressures in the range of 200/500, maybe 250/550?? would prevent a hyd plunger from even working at all.

This my friends, is the gray area. While common sense [no make that common practice] has been to run hyd rollers to lower rpm levels, it is not to say that you can't do it given the same design parameters. Again, not saying the motor is still making peak power up there, probably nosing off at a good clip. But just like in a comparison of flat tappets - hyd to solid, on a dyno, the solid always produces more at a given spec. Same would go for a roller. A solid roller profile will always be more radical and aggressive than a hyd roller profile.

motown, wasn't meaning to be insipid or shallow, just trying to learn alittle info about what you are doing. Grn69, that is some interesting info, if you are going to do that, why not just run a solid roller?

There ya go!

shhh dont tell. work with what you got is what i always say ..why spend when you dont have to .. no problem big red just pun back at you because my namehappens to be joe ..ha ha ha

Solid vs hyd is "THE" question. Is a hyd roller the most efficient in the above application? Maybe not. The only obvious reason I could see for using the prior disclosed combo would be the consideration of the softer seat timing with the hyd roller vs, the solid and the assumption that there will less valvetrain mantenance. The other option as hinted at by motown would be if you already had the lifters (same situation that I faced), then you obviously aren't staring down an additonal $500.00 purchase.

Either way, as long as it goes like all hell when I hit the loud pedal - :D

Joe (Motown)
No offense taken, just explaining what I meant as it appeared you thought I doubted your statement regarding a custom cam & that was not the case,,, just a wee bit "skeptical" regarding the part about makin power to 7250 but as I said, if it does more power to you & your builder ;)

Joe,(Grn69)
I have run a lot of hyd lifter deals with lash on solid cams in classes that require a hyd lifter but never in the configuration you just described.
With all due respect to the tech you talked to,
while I agree you can run a hyd as a quasi solid I for one would never bottom the lifter travel unless the lifter was specifically designed with very limited travel which 1+ turns is not.
The reason is very simple, if you go into "valve float" for any reason you relieve the pressure on the lifter & it will instantly pump up to the top.
Now, unless you have a very low lift cam if you add an extra 100 thou or so lift guess what happens next :D
It adds this lift everywhere including at overlap & in my experience having the valves off the seat an extra 100 thou at overlap is not the best plan even for an instant again unless you have a ton of clearance.
In other words, when the piston meets the valve you engine tends to get very unhappy ;)
Just my opinion.

And I agree, if you are going to run the thing as a solid why not just go to a solid unless there are restrictions as mentioned above??

Agree totally, that's why I went with a mild hyd roller in the 408. The Comp MkIV rollers I had, weren't going to work in the GenVI, so figured we might as well put em to use.

Regarding the high spring pressures and the effect on the lifter plunger??, can't comment on that, but it does seem feasible that if enough spring pressure is applied you could overide the check valve feature built into the lifter and cause it to bleed down - although that would appear to be an extreme amount. Again, assuming these are out of the box hyd lifters???

The other thing that was not touched on or mentioned in Motown's response was the use of oil restrictors up top and or bleed off of pressure in the lifter gallery which could also have the effect of limiting the hyd lifter's natural design to "pump up".

But as they say - 'hey don't shoot me, I'm just the messenger'.

Hey Mike, here's a novel idea!! Maybe you can put a call into the Governer of Cal-i-for-ni-a and ask him how to prevent pumping up!!!

Sorry guys, had the flu for a week now and am getting a little awnry - if you know what I mean.

yes the flu has been here also . im usually a nice guy