doubleduecedonzi

I had my 99 7.4mpi rebuilt two years ago. Now I'm loosing the efi going carbed. My original plans were to use a zz502 cam port these heads use my cmi headers with dry tails.well Plans changed.. I don't plan on keeping the boat long and decided it would be a waste so.
Where can I find the stock cam specks? I want to replace stock cam with one a little milder (stock mag cam). Basically biggest cam possible without making changes to stock valvetrain. My engine builder seems to think a cam with in .04 lift over stock cam would be simple swap. But isn't 100% sure. These are the l-29 vortech heads not the 330hp peanut ports. I'm fully aware of cast internal's.
Bottom line how much lift can these heads support Bone stock.
Thanks guys.

mike tkach

iTrader: (3)

go with the stock cam,you will see no gain by going with.040 more lift.i have several if you need one.

doubleduecedonzi

Thanks for the advise mike? I have the stock cam already. I was under the impression that any improvement or larger lift was better than none? I've read on several site guys using the l-29 motor and swapping cam to the stock magnum cam yet couldn't find reliable info on if the heads will except it in stock form. I realize just because people have used that cam doesn't mean anything was gained. That's why I'm asking and pleading my ignorance
In this thread. Then again i haven't confirmed that the mag cam is within .04 lift over the stock mpi cam nor do I know the max lift these heads can handle stock. I really need some help with that, motor is out and ready to tear into. School me.

f_inscreenname

I would think a 420 cam would work,
Crane #132561 hydraulic cam--Duration Advertised: 298° Intake / 306° Exhaust Duration @ .050'' Lift: 228° Intake / 236° Exhaust Valve Lift w/1.7 Rockers: .530'' Intake / .551'' Exhaust Lobe Separation Angle: 114°

SB

iTrader: (1)

L29 has a hydraulic roller

MILD THUNDER

iTrader: (3)

The stock L29 cam, and the 454/502 MAG MPI cams, should have the same LIFT. The L29 Cam just has very little duration. Like 204/209, compared to 224/224 of the Mag Cam. Both around .480 lift if i remember.

The 310HP MPI is dunzo at about 4500RPM. Installing the MAG cam, will help the engine rev to 5000. I would not recommend spinning much more than about 5000RPM with the stock internals. Mainly the rods.

MILD THUNDER

iTrader: (3)

That is a flat tappet mark 4/5 cam.

airjunky

iTrader: (2)

Do you have l29 cam or a gen 6 mag cam .? Thy are real close but utilize different heads intake ect .think.you have to refer to gmpp catalog for accurate cam specs on those ,I bought my last l29 cam from scoggins dickey .if your keeping f.I. you could be the first one to find out if the computer accepts a mag cam or not also .I was going to be that guy once but got cold feet

doubleduecedonzi

Thanks for the feed back guys. My current setup is a 99 7.4 mpi 310 hp (the l-29 motor which uses the vortech heads) I'm taking off the fuel injection and going carbed. The motor bored .03 over with forged JE pistons. I'll be using a hp 500 carb, stock l-29 heads, bought new 2 years ago during rebuild due to droped valve. I'm undecided on intake. And tying to gather Info on exactly what cam these heads can handle in stock form with no more than new springs. I realize I I could send them to machine shop and them set me up but I figured someone would have the knowledge here. From what understand the mag cam will work fine. I'm still wanna find out just how far I push the stock heads. I've read many threads of people using these heads but haven't found any reliable in depth details or facts. On guy on speed wake, think he's on here also said he talked to dennis Moore personally and said that the zz502 was direct swap with know changes needed. Zz cam has max lift of .544 I believe? Again I'm not wanting to run this cam any more as I'm no longer planing to use my headers. But if the zz cam can be ran on these stock heads with no changes made that would answer my question as to how much lift these has can take stock.

doubleduecedonzi

donman was the name of the fella I'm referring to about using the zz cam. He never made the actual swap before selling the boat.