When you work with COMP CAMS on a custom cam for your project, it stays confidential. But if you're just doing something like an XE274 intake lobe with an XE256 exhaust lobe, they can add that to their catalog if they want, because they don't tell anyone the name of the first person to order that combo. In a way, it stays confidential. If it goes into the catalog, the listing doesn't specify the heads or whatever of the first person to order it, it just gets a generic description describing the idle quality and such.

quote Originally posted by project34: I was hoping you might have had an answer to this mystery by having seen somewhere a published figure for a then-new, stock 4.9L cam. The 298o at 0.050" lift that you'd guessed at seems very high, so much so that I'd think it would render a Caddy engine unstreetable, which probably wouldn't be a good plan to appeal to a Caddy sedan's typical customers. Maybe that 298o refers to the stock 4.9L cam's advertised duration, rather than to its duration at 0.050" lift? Even Taijiguy's reground, aftermarket cam has only 215o degrees duration at 0.50" lift. My guess is that a new 4.9L cam at 0.050" lift would have been more in the neighborhood of 200o or somewhat less --- not at 298o.

Typo guys.. Sorry ... 198 degrees

Please take time to read this post I made on may 11

http://www.924board.org/vie...php?t=25060&start=75

[This message has been edited by ChadTanner (edited 07-10-2009).]

quote Originally posted by ChadTanner: what they done was legal,It just says something about a companies character.If I wanted to be a competive race team,I don't need to spend anything on R&D,just find a winning team,then ask Delta to grind me a cam like theirs and while were on the phone,ask "what else do you about their engine".(lol) I did do some research on 1.7 ford rockers for this engine with that cam.I'll dig up some stuff that might be a help to you. Thanks..... Chad

hell, if someone had the .498 e303 mustang profile in their 4.9L like john lagler used, along with those 1.73 ratio rockers, they would get .534 total lift... that would be a pretty bad-ass 4.9L

My guess is the lift would way exceed the breathing capabilities of the motor. Thanks for the clarification Chad. Do you have the motor in your Porsche running yet? I'd like to hear that sucker sing so Have some sense of what Mine will sound like. What kind of exhaust manifolds and mufflers are on the Caddilac in those clips?

quote Originally posted by Taijiguy: My guess is the lift would way exceed the breathing capabilities of the motor. Thanks for the clarification Chad. Do you have the motor in your Porsche running yet? I'd like to hear that sucker sing so Have some sense of what Mine will sound like. What kind of exhaust manifolds and mufflers are on the Caddilac in those clips?

what if the heads had larger intake valves and P&P'd?

[This message has been edited by stickpony (edited 07-13-2009).]

quote Originally posted by stickpony: hell, if someone had the .498 e303 mustang profile in their 4.9L like john lagler used, along with those 1.73 ratio rockers, they would get .534 total lift... that would be a pretty bad-ass 4.9L

quote Originally posted by stickpony: what if the heads had larger intake valves and P&P'd?

The .534" lift you mentioned is a whopping 39% higher than the stocker's .384" lift which you cited on the first page of this thread.

Assuming that much of an increase in lift didn't result in any valve-to-piston clearance issues that first would need to be addressed, whom would one recommend for the cylinder head work on a 4.9L to make that much lift a useful proposition with that engine?

quote Originally posted by stickpony: what if the heads had larger intake valves and P&P'd?

From what I've read the design of the ports just won't allow for decent flow. There reaches a point where you're just exceeding the capabilities of the heads to flow through the port regardless of how big the valves or how far they open. Personally, I was originally doing this as a budget build, and somewhere along the way I let myself be drawn in to thinking that I could make this motor into something it isn't. I'm trying to get back to my original plans. I'll just be happy when it finally runs! Regardless I know it'll be a big improvement over the 2.8.

[This message has been edited by Taijiguy (edited 07-14-2009).]

With good porting, production heads can find 5-25% more flow, depending on the basic design, but will still reach a lift at which they just won't flow any more air. This is called stalling. If the flow stays the same at even higher lifts, then it's okay to run more lift. The extra lift can still be beneficial, indirectly. But if the flow is actually less at even higher lifts, then you shouldn't be lifting past peak flow. Now, to tell you a fact, not to brag, I'm a natural at porting, on par with Joe Mondello and Tony Mamo. This is proven by the SuperFlow 1020 flowbench. And if you want good porting, I'll do it for $5 per port, because I give good prices to my fellow enthusiasts. But you pay shipping, and you do the polishing afterwards. The catch is, I currently can't include flowbench results for your particular heads.

I'd probably take you up on that, but shipping would be a killer.

quote Originally posted by Taijiguy: From what I've read the design of the ports just won't allow for decent flow. There reaches a point where you're just exceeding the capabilities of the heads to flow through the port regardless of how big the valves or how far they open. Personally, I was originally doing this as a budget build, and somewhere along the way I let myself be drawn in to thinking that I could make this motor into something it isn't. I'm trying to get back to my original plans. I'll just be happy when it finally runs! Regardless I know it'll be a big improvement over the 2.8.

That was well said, Taijiguy.

quote Originally posted by project34: That was well said, Taijiguy.

it is well documented that one can add sbc 1.94" intake valves to the 4.9L heads in place of the 1.77" stock intake valve size. Rick Stewart did it in his "4.9 performance" thread. he only used the delta mild drop-in cam with .480 lift, but he had the valvetrain modded to accept higher, i believe up to .06 higher, however, i dont know if any higher lift would be usable?? again, assuming the intake valve increase to 1.94" from 1.77" and a nice thorough P&P job, is total lift above .50" usable or just a waste of money?

If that's the thread I'm thinking of, I think the consensus was that it was an expensive build for the end result. I wouldn't be surprised if the bigger valves we largely a waste, as unless you have the room to un-shroud them, there isn't a lot of benefit. And as has been said before, there is a limit to how much the radius of the intake port will flow, plain and simple.
Don't get me wrong, I'm still doing as much as I can to the motor, but I'm keeping it real.

My 1.7 rockers showed up today. I just need to get someone to machine the rocker mounts to accept the pedestals. Apparently the machine shop is having trouble finding the right size freeze plug for the cam run. Once they get that and the machine work is done, II can start my build....

About time....

quote Originally posted by stickpony: it is well documented that one can add sbc 1.94" intake valves to the 4.9L heads in place of the 1.77" stock intake valve size. Rick Stewart did it in his "4.9 performance" thread. he only used the delta mild drop-in cam with .480 lift, but he had the valvetrain modded to accept higher, i believe up to .06 higher, however, i dont know if any higher lift would be usable?? again, assuming the intake valve increase to 1.94" from 1.77" and a nice thorough P&P job, is total lift above .50" usable or just a waste of money?

You can't know that without flow bench results. Cutting the heads for larger valves used to be the 3-angle valve job plus some porting, but these days we have the greatest invention since Adam and Eve: The "bowl-hog" the best ones can cut at 75 degrees. This takes care of about 90% of the porting that used to be required, and does so far better and faster, with far less iron dust into your lungs. And if you're going to do this, also spend the $40 for a good set of new 1-piece, undercut, swirl-polished, stainless valves, then have your machine shop put a small 30 degree back cut on each of them.

quote Originally posted by Taijiguy: If that's the thread I'm thinking of, I think the consensus was that it was an expensive build for the end result. I wouldn't be surprised if the bigger valves we largely a waste, as unless you have the room to un-shroud them, there isn't a lot of benefit. And as has been said before, there is a limit to how much the radius of the intake port will flow, plain and simple. Don't get me wrong, I'm still doing as much as I can to the motor, but I'm keeping it real. My 1.7 rockers showed up today. I just need to get someone to machine the rocker mounts to accept the pedestals. Apparently the machine shop is having trouble finding the right size freeze plug for the cam run. Once they get that and the machine work is done, II can start my build.... About time....

after all his work, rick ended up with 285 hp and 380 ft lbs at the crank, and that was before he changed out the stock pushrods for the corrected longer pushrods, AND that was with an untuned PCM. with the proper tuning, i would think an additonal 20 HP could be added to that, getting close to 300HP.. yes, the HP doesnt really justify the means, BUT the TQ sure's hell does

anyways, also take into account that it is the lightest V8 one can put in the fiero, power to weight ratio is always a consideration.

honestly, an LS4 is probbaly a better bang for the buck because of its ability to be upgraded, BUT, how much power do you REALLY need on the street?

Well, I don't have the kind of coin it would take to do all the stuff he did anyway. So I'll just do the best I can with what I have and be happy with what ever it ends up being.

On a different note, someone on here was offering machine shop services. Anyone remember who that was? I'm wondering what they wouldl charge to machine my rocker supports for the new rocker pedestals.

Any competent machine shop can do that, there should be one in your area. Or in the nearest big city.

quote Originally posted by Isolde: Any competent machine shop can do that, there should be one in your area. Or in the nearest big city.

I know. The place that has my block could do it. I was just wanting to see if it might be cheaper, and I could throw some business to a PFFer.

Using the key duration and lift numbers cited on the previous page of this thread, and the duration for the stock cam helpfully cited by ChadTanner on the present page, I updated the following table:

code:

---

                                    1st Dur. Level  2nd Dur. Level  3rd Dur. Level
                          Stock Cam    Delta Cam       Delta Cam       Delta Cam
                          ---------    ---------       ---------       ---------                         
Int/Exh Duration @ 0.050"    198          205             215             220
Int/Exh Lift                .384"        .480"           .455"           .498"          
Lift/Duration Ratio          1.94         2.34            2.12            2.26

---

The most "unusual" cam in all of this appears to be the stock one, with easily the most conservative lift-to-duration ratio of the four cams we've covered. However, that is a cam originally designed for a Caddy, so I'd think its relatively conservative specs shouldn't be all that surprising.

The cam you purchased for your 4.9L swap, Taijiguy, referred to in the above table as the "2nd Dur. Level Delta Cam," has the second most conservative lift-to-duration ratio of the four cams we've discussed. However, I'd have to agree that as you'd mentioned on the first page of this thread, "...if the specs are even close, the lift is a lot better than stock."

That does seem a healthy increase --- .455" lift versus the stock .384" lift --- doesn't it?

I think yours will prove to be an interesting swap, one that is very streetable and in line with your objectives for your Fiero.


Please keep us posted on it.

Well??? Thanks for the read guys. Very interesting and informative. Any news how these cams are working for you????

Just a bump to keep this thread out of the archives. Haven't got my motor together yet, anyone else?

quote Originally posted by Taijiguy: Just a bump to keep this thread out of the archives. Haven't got my motor together yet, anyone else?

bump

quote Originally posted by Taijiguy: On a different note, someone on here was offering machine shop services. Anyone remember who that was? I'm wondering what they wouldl charge to machine my rocker supports for the new rocker pedestals.

I do that work.

Does Delta have a turbo cam grind for the 4.9 ?.... ( little to no overlap )

quote Originally posted by MaxCubes: Does Delta have a turbo cam grind for the 4.9 ?.... ( little to no overlap )

They'll custom grind your cam any way you want. You need to give them your old cam anyway for a core, or you can just send it to them and they'll grind it however you want.