454 Gen 6 Cam - Chevelle Tech
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post #1 of 17 (permalink) Old May 9th, 09, 10:48 PM Thread Starter
Robert
 
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454 Gen 6 Cam

Well, I don't own a Chevelle guys, but this is probably the best Chevy forum site out there, and I do own a '90 454SS truck and have a lot of cam questions with the following engine-

GEN 6 BBC 454 Stock shortblock (1997 I think)
9:1 compression
Vortec L29 Heads 99cc chamber volume (small ovals) Further Head specs-
Intake Port Flows
CFM @ Lift
63 .100
121 .200
165 .300
198 .400
226 .500
242 .600
Valve Size: 2.065"/1.725"
Chamber Volume CC: 99cc
Spark Plug Position: Angled
Spark Plug Size: 14mm
Spark Plug Reach: 0.708"
Spark Plug Number: RS12YC
*L-29 exhaust port = 81.2cc.
*L-29 intake ports = 233.2(S) and 239.5cc(L).

Stock L29 Cam Specs-
Camshaft type: Hydraulic roller Camshaft lift (in).480 intake / .483 exhaust Camshaft duration (@0.050-in)204 intake / 209 exhaust


Anyways, my question is-

I'm in need of a cam. It has to be a hydraulic roller and make a descent improvement in power, but not so much lift or duration that there is a danger of hitting the piston with the valves or requiring changes in the valve train such as rocker stud or spring changes. Yes, I said not even spring changes, so this would be a mild cam, if you haven't already gathered that, with an RPM ceiling of say 5,500 max. I know the factory heads have a limiting net-lash set up, but I don't want to mess with the valve train, not even springs. I do not care about the idle quality, emissions, or whether the cam is computer compatible. I do care about improving power, keeping it a hyd roller, and piston to valve clearance. I've heard good things about the XR276, but I have also heard that the max lift on these heads is .500. The truck weighs 4300 lbs, has a TH400 with 2,500 stall, 3.73 rear end, dual cat free exhaust with long tube headers, no computer, dual plane intaKE with dual Edelbrock AVS 600s. I've also been looking at the following GM cams and was wondering if anyone had any experience with these:

ZZ502/RamJet 502 cam
Camshaft type: Hydraulic roller Camshaft lift (in).527 intake / .544 exhaust Camshaft duration (@0.050-in)224 intake / 234 exhaust

454HO
Camshaft type: Hydraulic roller Camshaft lift (in).510 intake / .540 exhaust Camshaft duration (@0.050-in)211 intake / 230 exhaust

Oh, one last thing, if someone could ballpark an hp and tq estimate for these cams that would be great, stock the truck makes 290 hp, and I think 410 tq.

-Thanks for the help and for reading my novel guys.
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post #2 of 17 (permalink) Old May 10th, 09, 2:25 PM
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Greg
 
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Re: 454 Gen 6 Cam

I am in pretty much the same position as you. I have a 7400 Vortec out of a '00 Chevy C2500HD installed in an '86 short bed C10. I pulled the MPFI intake off and stuck an Edelbrock Performer 2-0 and 750cfm carb on it. I have Hedman Elite long tubes going into 3" X-pipe exiting through 3" Aerochamber mufflers. Trans is a 4l80e with stock converter and the rear is currently 2.73 10-bolt peg leg. I can do some serious burnouts from off idle, but it runs out of breath by about 4500rpm.

I was looking at a low budget cam swap to bump the rpm range up. The GM billet rollers you mention are about the cheapest quality part out there, but I think you will definately need a valve spring upgrade. The stock L29 springs are not performance parts.

Anyway, I found a Mercruiser GM billet take-out cam at Competition Procucts for $35 plus shipping.

Competition Product M1 Cam

The specs for the original cam in your L-29 Vortec motor are:
GM PART #12552296
.004 280,299
.006 266*/284*
.050 204*/209*
.200 113*/114*
Lift .480/. 483
ICL 115.5*
ECL 120.5
LSA 118*

This Mercruiser cam specs are:
GM#12551622
.004 300*/ 300*
.006 288*/288*
.050 225*/225*
.200 125*/125*
Lift .483/. 483
ICL 109*
ECL 122*
LSA 115.5*

You can see the lift is the same, but you get about 20* more duration at .050 and the LSA is a tad tighter. This cam would be fully compatible with the net lash valve train, and probably the computer.

For valve springs, I am going to use the 454HO springs. I have been told that these will drop right in without machining. Comp Products has those too for a good price.

454-502HO Valve Springs

I am expecting a noticable seat of pants improvement and hopefully it will pull to at least 5000rpm. Total cost, if I don't need to buy a timing set, should be less than $200.

I'm interested to see which way you go with yours.

-greg
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post #3 of 17 (permalink) Old May 10th, 09, 5:49 PM
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Re: 454 Gen 6 Cam

Quote:
Originally Posted by 454HO C10 View Post
For valve springs, I am going to use the 454HO springs. I have been told that these will drop right in without machining. Comp Products has those too for a good price.

454-502HO Valve Springs
Be aware that you will need two sets (16 total pieces) of valve rotator eliminator shims; and that you may need MINOR grinding on the exhaust guide-to-spring seat radius in order to get the shims to drop all the way into the spring pockets.
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post #4 of 17 (permalink) Old May 12th, 09, 12:34 AM Thread Starter
Robert
 
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Re: 454 Gen 6 Cam

Well, I decided on the mercruiser cam as well. I don't know if I'm going to switch out the valve springs, as I don't want to do any grinding of the guides. I really just want this motor to put out at least 350 hp, and it seems like an uphill battle, and its a big block, what gives,lol. I have headers, dual plane manifold, and soon this merc cam, so maybe...
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post #5 of 17 (permalink) Old May 12th, 09, 12:38 AM Thread Starter
Robert
 
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Re: 454 Gen 6 Cam

I was looking at cams from comp cams as well, and anything with around the same duration as the merc cam has at least .510 lift. Is there any reason why mercury marine would install such a high duration cam with so little lift, I mean besides the valve train limitations?
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post #6 of 17 (permalink) Old May 12th, 09, 8:19 AM
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Re: 454 Gen 6 Cam

I have a couple of steel cores at Delta, they have a ton of masters and their work is second to none...let me know if you need one of these cores. I think the cores are actually the Mercruiser you're looking for.

Gary Adrian
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post #7 of 17 (permalink) Old May 12th, 09, 10:07 AM
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Re: 454 Gen 6 Cam

Quote:
Originally Posted by 454Vortec View Post
I don't know if I'm going to switch out the valve springs, as I don't want to do any grinding of the guides.
My suspicion is that is a HUGE mistake.

I don't trust the original valve springs or the rotators any farther than I can throw them. Mine went straight into the recycle bin.

The grinding of the valve guides is SO INCREDIBLY MINOR that a sixth-grader with adult supervision could do it. But I think I did make a mistake; I said it was on the exhaust guides--and now that I think about it, it's the intakes.

Either way, it's going to be TOTALLY OBVIOUS. One set of guides (the exhausts???) is pressed into the head casting. There is NO problem getting the rotator eliminators to fully seat, because there is no radius at the bottom of the guide where it meets the spring pocket--the material of the head is actually scalloped away. The other guides are a machined part of the head casting, and two guides on each of my heads (as in--NOT all of them!) needed to be touched with a Dremel to remove a burr preventing the rotator from fully seating in the spring pocket. If the rotator FULLY seats--you don't need to grind.

Quote:
Originally Posted by 454Vortec View Post
I really just want this motor to put out at least 350 hp,
Measured HOW?

GM uses the full SAE protocol for net horsepower. GM horsepower is always "under-rated" (GM rating always exceeded) on an aftermarket dyno, in part because pretty much nobody in the aftermarket will bother to use the complete SAE Net protocol--and so the aftermarket dyno registers higher than what it would if the protocol was followed.
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post #8 of 17 (permalink) Old May 12th, 09, 5:13 PM
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Greg
 
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Re: 454 Gen 6 Cam

For a little more info, check out my $35 cam thread in the Performance forum - https://www.chevelles.com/forums/showthread.php?t=264788

Why did Merc use such low lift? Could be because of the wimpy valve springs in the L-29 heads.

-greg
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post #9 of 17 (permalink) Old May 12th, 09, 10:25 PM Thread Starter
Robert
 
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Re: 454 Gen 6 Cam

Can the grinding be done with the heads on the block?

As far as the 350 hp, I'd like that at the flywheel please.
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post #10 of 17 (permalink) Old May 12th, 09, 10:47 PM
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Re: 454 Gen 6 Cam

Quote:
Originally Posted by 454Vortec View Post
Can the grinding be done with the heads on the block?
Yeah...I suppose. You'd want to be careful to block any openings into the lifter valley; and don't get too carried away with the grinding. I'd want a shop-vac running; and the open hose RIGHT NEXT to the Dremel, and in the direction the filings are coming out. TEST FIT THE SHIMS FIRST and maybe you'll get lucky and won't actually have to grind. Considering the little amount needing to be removed, a hand file or emery cloth might be a better idea than a powered grinder. In any event, don't use a STONE.

Quote:
Originally Posted by 454Vortec View Post
As far as the 350 hp, I'd like that at the flywheel please.
It's always "at the flywheel" when measured on an engine dyno. One issue is the temperature of the air coming into the carb; it shouldn't be any colder than what the engine is going to get when installed in the car. Therefore the fuel curve can't be artificially enriched due to cold intake air.
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post #11 of 17 (permalink) Old May 13th, 09, 6:34 PM
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Greg
 
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Re: 454 Gen 6 Cam

Schurkey, any reason why the clearancing couldn't be done on the rotator eliminators instead of the head?? I'm thinking a few seconds with a countersink bit in a drill press should put a nice bevel on it.

-greg
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post #12 of 17 (permalink) Old May 13th, 09, 7:29 PM
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Re: 454 Gen 6 Cam

I just put a Gen VI 454 together with the L-29 heads (shaved .030 to bump up compression a little) with a Lunati 60211 hydraulic roller, the recommended Lunati valve springs, some Harland Sharps, performer RPM airgap, and a 750 from Sean Murphey.

Shurkey is dead on with his posts about the valve springs being crap. I would not attempt any cam upgrade without tossing those springs. They cannot take anymore cam than stock, basically.

I had to do exactly what he said to get the rotator eliminators to seat properly as well. I also had to order some pushrods to get the proper length. (base circle cam difference as well as .030 on the heads) I think you could remove a little from the rotator eliminator rather than the head if you wanted to do this on the motor. Should be careful not to take out too much so the eliminator could walk around on you though.

I am not sure where my motor will fall down, but it is certain to be before 6K. The intake ports on these heads simply won't permit much more regardless of the cam. Some of the computer predictions were as high as 425 hp / 550 ft-lbs and as low as 380 HP / 480 ft-lbs. I am sure they were about as good as any other guess though. My goals are a lower RPM tire shredding torque pig, so I don't think I will be disappointed. I hope I can help further, but listen to Shurkey, he has been dead on with his advice.

65 Chevelle Gen VI 454, Lunati HR Cam, ST-10 4 speed, Moser 9", 4-wheel disc
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post #13 of 17 (permalink) Old May 14th, 09, 8:17 AM
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Re: 454 Gen 6 Cam

It may not be accurate, but it's a comparison. The TBI smallblocks make more torque at lower rpm's than vortecs, but the vortecs pull away at higher revs. Looks like the swirl ports help with lower rev grunt, plus the heart shaped chambers are known power makers. Too bad the intake port on the big blocks isn't a bit bigger, that would make it the best all-around street head for us cheap guys that run unported OEM parts.

Gary Adrian
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post #14 of 17 (permalink) Old May 14th, 09, 3:04 PM
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Vince
 
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Re: 454 Gen 6 Cam

Think a .600 lift cam will get in there? In terms of p/v clearance and/or retainer to guide? I would pull a set of intake and exh springs, and measure how much retainer to guide clearance you have before doing anything. Then, measure how much p/v clearance you have at TDC, this way you can calculate what your clearance will be with the cam your thinking about running (you can ask the manufacturer what your projected clearance will be if you know some of the variables).

Sounds like you want to make some power. I would go with something in the 230 @.050 if you can get it in there. I had the clearance for a 231/239 .600 Voodoo in my 454HO which doesnt have much in terms of valve reliefs. I actually took out my 231 @.050 cause I thought it was too mild. So did a friend of mine who had a 233/236 HR cam (GRN69CHV right here). Actually, his cam is for sale in the classifieds. You start to lose vacuum in a 454 once you get around the 240+ range.

*69 SS 502 EFI /224* HR/9.8:1/T56/3.90 11.5/124mph
*11 C6, 6.2, 6spd
*96 Stang 6.0 turbo 10.5/135mph
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post #15 of 17 (permalink) Old May 14th, 09, 11:26 PM Thread Starter
Robert
 
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Re: 454 Gen 6 Cam

Well, I might just take the heads off if there is too much material to take off in a decent amount of time with a file. Here's the thing though guys, I've never done any head work, haven't ever even replaced springs.

I have a bar type valve spring compressor and more than enough other tools in my garage to do this but...like I said I've never done this so I don't know what all I would need it terms of parts besides the valve springs. I mean will I need new seals, and retainers, etc? If someone could give me a detailed list that would be great.

As long as the spring height is the same I won't need new pushrods right? If I get a camshaft with the same base circle as stock that is. I've been looking at the COMP CAMS 290HR cam too, seeing as there hasn't been any issues with 600 valve lift and p/v interference. Below are the specs.

290HR
290
290
232
232
.578
.578
110
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