Cam Recomendations for a 383 SBC

[SlowMalibu]

I know I may be opening a can of worms over here....but I need some help with this.

So here it is....I am putting a 383 together, street car, fun weekend warrior

Compression is around 10.5 to 1.
Heads are GMPP Fastburn Vortec aluminum heads with 2" intake and 1.55" exhaust valves. Based on my research these heads flow around 250-260 CFM intake and 180-190 CFM at around .550 lift.
Intake is Vortec Perfromer RPM
Planning on Holley Terminator 4BBL
Manual transmission - 4 or 6 spd.
3.73 gears
81 Malibu 2 dr
Manual brakes

Engine has all forged rotating assembly capable of 7000 rpm

I don't mind a solid cam

I have followed David Vizard's cam selection and came up with the following specs:

cam 1: 106LSA, 288 intake 296 exhaust advertised duration, 0.550 int./0.570 exh
cam 2: 106LSA, 285 intake 295 exhaust advertised duration, 0.532 int./0.555 exh.
cam 3: 106LSA, 300 intake 308 exhaust advertised duration, 0.516 int./0.525 exh. - already have this one

What do you guys think ?

[Tom68]

What lobe families ? Adv dur means nothing without that.

[SlowMalibu]

That's what I need help with.....I have no idea what you are asking. I have been looking at cams for a while and quite frankly I don't know why there are classified in oval track, drag etc on top of brand specific classifications. What is the difference between a 'normal' and a tight lash cam is ? Why do solid roller SBC cams only come n .600+ lift ? See, all this stuff is new to me and I need some schooling.....if you have the time to explain it to me I would really really appreciate it

[rgalajda]

Duration 291@lash - 232@.050 - Lobe Lift .333 - Valve Lift with 1.5/1.6 RR .500/.533 - LSA 108 or 109

As an example this would be considered a Max street Roller Hydraulic cam profile for most people. An endurance type of grind ,meaning will last for more miles. Max profile for street driving.

Duration 280@lash - 221@.050 - Lobe Lift .339 - Valve Lift with 1.5/1.6 RR .509/.542 - LSA 108 or 109

This is an example of a Fast Street profile

A 108 to 109 LSA would probably produce best results depending on rocker ratio used.

Tell us more of what you want, with priorities. Be realistic. such as , max power, better drivability, fuel mileage, endurance.

Do you have .050'" specs for your camshaft?

[bigcam406]

Lunati Voodoo 20120713 Hydraulic Roller

.560/.565" lift
243/251 duration @ .050''
110 lsa
2800-6800 rpm range

Don't waste your time and money with todays flat tappet cams.

[bobmc]

download the Comp Cams lobe profile catalog and look at page 71, the "MI" on the left stands for major intensity which is the difference between advertised duration and .050 duration, a lower major intensity figure indicates faster opening and closing-typically called more aggressive lobe, the .050 duration compared to max lift number could be called overall intensity- .600" lift @ .050 is more intense than .500" lift @ .050 etc, you might want to use a higher number major intensity and lower overall intensity lobe for a street engine, different brands of cam use different methods of calculating advertised duration which makes it hard to compare major intensity between brands

[BobbyB]

I know I may be opening a can of worms over here....but I need some help with this.

So here it is....I am putting a 383 together, street car, fun weekend warrior

Compression is around 10.5 to 1.
Heads are GMPP Fastburn Vortec aluminum heads with 2" intake and 1.55" exhaust valves. Based on my research these heads flow around 250-260 CFM intake and 180-190 CFM at around .550 lift.
Intake is Vortec Perfromer RPM
Planning on Holley Terminator 4BBL
Manual transmission - 4 or 6 spd.
3.73 gears
81 Malibu 2 dr
Manual brakes

Engine has all forged rotating assembly capable of 7000 rpm

I don't mind a solid cam

I have followed David Vizard's cam selection and came up with the following specs:

cam 1: 106LSA, 288 intake 296 exhaust advertised duration, 0.550 int./0.570 exh
cam 2: 106LSA, 285 intake 295 exhaust advertised duration, 0.532 int./0.555 exh.
cam 3: 106LSA, 300 intake 308 exhaust advertised duration, 0.516 int./0.525 exh. - already have this one

What do you guys think ?

Fill out Mike Jones cam recommendation sheet at Jones cams, or call him. He can regrind your existing cam too.

[bobmc]

left out a couple of words in my long explanation, "the same" .050 duration, example- a .600" lift on 230 deg @ .050 lobe is more intense than a .500" lift on 230 deg @ .050 lobe

[PRH]

My understanding is that cams with “tight” LSA’s(more overlap) can create tuning challenges with EFI.

Just something to consider.

[mt-engines]

My understanding is that cams with “tight” LSA’s(more overlap) can create tuning challenges with EFI.

Just something to consider.

Thats always been misinformation.

[Cris]

SlowMalibu:

I see you are a new member. Mike Jones of Jones Cams runs this site, and he is probably one of the best resources for cams you will find. Do not make the mistake of picking a catalog cam based on internet reading. You will not (unless you are really luck) get the most out of your build this way. I see you have already bought your heads. Heads and cam are the biggest bangs for your buck. I see countless builds where people are unduly fussing over header size, mufflers, oil, etc, etc, etc. Put the most thought, effort, and money into heads and cam.

I have no affiliation with Jones Cams. Call him and have him work up a cam for you, it will be a little more money, but it might make SlowMalibu into FastMalibu.

And did I say heads and cam?

[Steve K]

My understanding is that cams with “tight” LSA’s(more overlap) can create tuning challenges with EFI.

Just something to consider.

Thats always been misinformation.

If its' a self learning type based on vacuum a tight LSA with low vacuum can cause it to run on the rich side. Wider LSA such as 114 deg would have higher vacuum and run better. Programable EFI can work around this. Based on experience...

[Steve K]

Lunati Voodoo 20120713 Hydraulic Roller

.560/.565" lift
243/251 duration @ .050''
110 lsa
2800-6800 rpm range

Don't waste your time and money with todays flat tappet cams.

I run this cam in my 406. Great cam but low vacuum caused me problems with self learning efi. Switched back to carbs and runs great.

[mt-engines]

My understanding is that cams with “tight” LSA’s(more overlap) can create tuning challenges with EFI.

Just something to consider.

Thats always been misinformation.

If its' a self learning type based on vacuum a tight LSA with low vacuum can cause it to run on the rich side. Wider LSA such as 114 deg would have higher vacuum and run better. Programable EFI can work around this. Based on experience...

Similar to a carb right?

[Dave B]

Wow ,guys if you can't get a camshaft to work with efi, you really should take up another hobby .Maybe cookies? Some of you guys are why electric cars are needed!!!!!!!