Empatho

I'm going to start building the engine in july because I got tired of knowing that some of the new model minivans have more horses then me and that's not fun. I'm stroking the original engine on my 78 vette(H-beam connecting rods, forged steel crankshaft, 18cc invrt. dome pistons) Vortec heads(accommodate up to a .480" lift cam) Edelbrock Performer Vortec Intake Manifolds and a JET Streetmaster Quadrajet Stage 2 carb should I add a 1" carb spacer?(yes or no) comp. should be around 9.7:1 with the 64cc from the vortec heads.
the car is a daily driver and I want 2 stay that way, I want a lopey cam but I dont know whish cam to get that would be best for my combination that would work with the lift limit of the vortec heads I didnt now who to ask so I came here,
any ideas?
I have long tube headers with dual exhaust, about how mush horse power is my engine going to put out?

SteveG75

My $0.02. That lift limit is killing you.

383's can tolerate a much bigger cam than a 350. Get better heads or have the Vortecs reworked. Also, the Performer is better at low RPM duties.

What kind of driving? Desired RPM range? Street only? Strip only?

Any cam mild enough to work with the Vortec lift limit will be very mild with a 383. This means that it will idle nice (no lope), lots of torque, and probably top out about 4500 rpm.

Edit: Oh, no need for a spacer on this motor.

Another comment. H beam rods and forged cranks are good for hi-rpm motors. The heads and intake are good for street motors turning no more than 5500 rpm. You have a classic parts mismatch.

Empatho

I got the heads from Scoggin Dickey and they told me "that they can handle up to 0.550" lift hydraulic camshafts" so I can get more lift out of them.
The car is going to be a daily driver and I dont whant to get it over 6 thousand rpm, maybe take it to the track some times.

Empatho

I'm planing on getting a nitrous oxide kit :o and I need a strong bottom end

waterplay

My recommendation is to go with the Comp Cams XR294HR. This will make around 550hp and the RPM is band in a 383 is up to 6300. This is with 9.6 to 1 compression and AFR 195 heads. You will also want to go to a 1.6 ratio rocker. You can lower the RPM band by staying with the 1.5 rockers. This will also lower the HP a little. This combo is still very streetable. It is also compatible with Nitro but you may not need it. My thought is it is better to have some extra power and not use it that to not have it and want or need it. Don’t let the “soccer” van get the best of you!

SteveG75

Personally, I like Hydraulic roller cams but are you willing to spend the money? Now, almost any hyd roller will have some very good lift numbers. This XR294HR has .540/.562 lift with 1.5 rockers so it won't work with your valve springs. The power band is also advertised to start at 2800 RPM. It may be lower in a 383 (approx 2500 rpm) but you are talking about a cam that has 242/248 intake duration. Now Comp also likes to grind on a narrow LC (110 in this case) which helps build cylinder pressure. However you may not want that with nitrous since it may be too much pressure.

Now, I am partial to Crane Cams and have the HR276 in my 350. It specs out at 214/222 @.050 / .488/.509 total lift. I can cruise at 2000 rpm and it pulls to 6000 easily. Chevy puts the next larger cam in the ZZ383/425 HP motor. That is the Crane HR284 (222/228@.050, .509/.528 total lift).

A roller cam is a great thing but very expensive to retrofit (~$800+ all told). In your case, the Vortec heads will not handle the lift of a roller cam with a duration that takes advantage of your cubic inches. For example, my cam would work but it would be very mild for a 383 (heck, it is on the verge of too mild for a 350).

So, since we have eliminated most rollers due to your springs, lets look at a couple of hydraulic flat tappet cams.

Now, I am not big fan of Comp Cams (two wiped XE cams) but they do have a Nitrous HP line. It has wider lobe centers to help with cylinder pressure and a split pattern (longer exhaust) to help get rid of the exhaust. The two that jump out at me from the catalog are:

NX268H 2000-6200 rpm, 224/236@.050, .477/.490 lift. 113 LC
NX268H 2400-6500 rpm, 230/244@.050, .487/.501 lift. 113 LC

Now, I think Comp exaggerates the RPM range (low and high). I also like a slight smaller cam for street manners but the 383 will help tame the larger cam. You really have to decide what you want.

Hopefully, this info will be a little more helpful. Remember though, a 383 is a torque monster already. Nitrous works well at hi RPM but a lower RPM's (below 3000) it can kill a motor. After all, HP=Torque x RPM/5252.

So a 150 HP shot at 3000 RPM increases your torque by ~263 ft lbs. Be ready top replace U-joints, half shafts, etc. Just my $0.02.

mandm1200

Before choosing a cam, make sure the heads can handle the lift. Do you have a part number for the heads. The reason I ask is that there may be a lot of people who do not know that GMPP as released 2 new Vortec Bowtie heads. They are similiar to the old ones but GM has essentailly made them more race friendly. The new style heads will have the bowtie logo on them. Allow for more lift, screw in rocker studs and some other enhancements. They also come in 2 sizes. An recent article had them well over 600hp. They are not the kid toys of the previous L31 heads.

Verify what you got, and then get back.

Large-Port Vortec Cylinder Head Flow
INTAKE EXHAUST
Lift Volume Lift Volume
0.200 128.6 0.200 100.8
0.300 188.4 0.300 138.6
0.400 234.8 0.400 154.4
0.500 257.2 0.500 152.5
0.600 263.2 0.600 163.8
0.700 269.1 0.700 167.0

Empatho

thanks guys for the info
I wont get nitrous
do they lope because I want a cam with some lope not mush but some to get the peoples attention
if I'm not using nitrous should I look into another cam

Empatho

I bought the heads from Scoggin-Dickey and they "machin the valve guides for clearance, install high performance Z28 valve springs with lightweight LT4 retainers. This produces a high reving cylinder head that can handle up to 0.550" lift"
I dont want to use a Hydraulic roller cam I rather use a hydraulic flat tappet cam

thevetterisbetter

If I were to do it all over again, I would wait a little while longer, save some money and go roller. As it is, I went with the Comp Cams XE268H for my 383 with an Edelbrock RPM Performer, AFR 190 heads, 1:6:1 Pro Magnum roller rockers and dynomax headers. The engine dynoed at the flywheel at 424 hp and 440 lb-ft of torque. Don't know what it does at the rear wheels. But it has a definite lope with a 2.5 inch exhaust.

I know that the Comp Cams XE line isn't very popular due to all the wiped lobe issues here, I bought it before all those reports started coming out and if I were to do it all over again, I would steer clear.

Empatho

I found a cam
first cam
Lunati Voodoo
Basic Operating RPM Range: 1,800-6,200 RPM
Advertised Duration: 268 int./276 exh.
Valve Lift: 0.489 int./0.504 exh. lift
Lobe Separation: 110


any ideas if this cam would work with my combo or do you guys suggest a better cam I want a cam with a nice lope without fouling the plugs

vetteaddic

well if your heads (springs) are good for 550 lift get a cam with 540 lift to be safe,now about lope with a 383 a cam like that is going to be tame ,I had a xr288hr in my old 350 with forged pistons and Edel heads and it had a killer lope to it I loved it so did others,some here would say thats too big but thats the way I am, the engine would scream 2500 to 6000 Now I have a 427 sb with a 622 lift 244@.50 that idles like a kitten,I lost my badass lope but still have plenty of power to rip my rearend apart...

gdh

take a look at this site - I have posted it many a time over the years for ppl looking at building and matching components. I gives you dyno results of the combos as well.

http://www.ryanscarpage.50megs.com/combos1.html

Dwaynes69BB

I was going to suggest that you take a look at the Lunati VooDoo cams.

I'm planning to run the 60103 in my Vortec headed 383 going into our Wagon Project.

Also, the Vortec heads are a good choice for the 383. They are definatly superior heads to the RPM's

check out these flow test.
http://www.chevyhiperformance.com/te...598/index.html

I have set up two sets of the Vortecs with LT4 springs and retainers to handle up to .550 lift.

I guarantee, they will put a big grin on your face!

Empatho

that is great information I see that the vortec heads have potential
I think I will go with the same cam any other choices or why not to use?

Dwaynes69BB

Doh!, I should have reconized those specs.