I'm currently waiting on my 383 shortblock to be done. I was figuring on putting the Comp XR276HR cam from the 350 in the 383. What do you guys think? Will it be enough cam? Streetability is not a major concern. This car is not a daily driver.

Mods:
383 4 bolt roller block
Scat 4340 Crank
Scat 4340 Rods
KB Flat top pistons 10.5:1 static compression with 68cc chambers
AFR 195 heads
1.6 roller rockers
Stealth Ram
Holley Commander 950 ECU
Raptor 700 trans
2800 stall converter
3.89 gears

Grumpyvette or RBL or any other HSR saavy people, feel free to chime in.

 

Rick I'm going through the exact same thing. I just sold the XR276HR before dropping it into the stock short block, and decided to build everything around a built 383. OMINOUS_87 convinced me to go one cam bigger for the Stealth Ram.

I'm doing the 230/236, and getting it ground on a 113 instead of the 110. CHP made 491 hp with that cam, TFS heads, and 1 5/8 long tubes on a carbed 383.

I guess you could go even bigger since you have more exhaust than that, but then vacuum goes to hell and it may want to make power above 6k where valve float may zero out what you'd be potentially gaining anyway. With your 195cc runners that's as far as I'd go. Your stall and gear are good for it too.

You may have a shot at running .5 quicker with that combo vs. the 350 combo. Whatever you decide, keep us posted because mine won't be done for over a year.

 

Rick the 230-236 would be a good choice like said above, but honestly the 236-242 extreme energy on a 112 would be a better way to go. I had this cam in my old 383. I switched from the 224-230 extreme energy. You will be pleased with the results and gain a few tenths over the 230-236 cam. I have the 224-230 cam in my 355 right now and it is running 12.30's at 112mph

 

One of the biggest mistakes most people make is trying to run a cam similar to what's in their buddy's engine has with a differant combo. You must always take into account YOUR TOTAL COMBO, before picking a cam. What works for me may not work in your combo.

Im useing this cam in my 11:1 cpr 383 now with the custom stealth ram, its a great cam when you add a 150 shot of nitrous in my particular engine

http://dab7.cranecams.com/SpecCard/D...1=Display+Card

I will be going to 11.5:1 cpr pistons and one of the cams below in the next few months

http://dab7.cranecams.com/SpecCard/D...1=Display+Card

http://www.crower.com/misc/cam_spec/...um=00471&prn=1

WHY... well heres the torque curve in a 350 11:1 cpr engine with a similar head flow and intake flow but a restricted exhaust (thats dyno info rear wheel tq BTW) add a good exhaust and that should make a great cam for your 383



now remember IM NOT TRYING TO BUILD A RACE ENGINE, I can run fast enought to totally embarass Z06 corvettes on street tires now,(no I won,t give you ET info) but adding a small amount of duration will allow even better power at 6000rpm, what I want is to totally embarass a few lightly modified vipers my friends own not just beat them and thats BEFORE I hit the giggle gas button!
if you talk to a cam company, keep in mind a stealth ram is basically a TUNNEL RAM INTAKE CONVERTED TO EFI, IT HAS TOTALLY DIFFERANT FLOW AND RPM CHARICTERISTICS THAN A TPI INTAKE

RICKITPI ID PICK ONE OF THESE TWO CAMS, and the CROWER #00471 with its tighter LSA would most likely be my pick with your slightly lower static compression ratio

http://dab7.cranecams.com/SpecCard/D...1=Display+Card

http://www.crower.com/misc/cam_spec/...um=00471&prn=1

 

My Comp cam XR276HR-12 has a 112 LSA. The part number is 8-503-8.

Specs w 1.5 rockers are:

.503/.510
224/230 @.050
112 LSA
108 ICA


This cams rocks! It's a good choice for a TPI and would still work great in a Stealth-ram.

 

Thanks for all your replies.
I really don't want to spin the motor over 6200 rpm. Looking at some of the bigger Comp cams, 288 in particular, the peak hp is around 6400 as shown on DD2000. The Crane cam Grumpy shows, it peaks at 6800. Keep in mind, I am running 1.6 rockers with Comp 987 springs. AFR says valve lift limit is .550”. Most of these cams will push over .550” with 1.6 rockers. I really don’t want to invest in a new valve train at this time, since all my stuff is only about 6 months old.

 

Ricktpi

Valve train stability is the biggest concern here. Running anything bigger then the 987 and you run the risk of colapsing a hydraulic lifter. With the 987 kit you should have no worries with the 230/236 cam and 1.6rrs. The 236/240 cam in my opinion is about as big a cam as someone would ever want to run as a hydraulic roller setup, the outer edge in my opinion. Although eveyone is doing it Comp actually recomends against 1.6 rockers for the bigger cams in this product line as it becomes harder to keep them under control even with the 987s.

Comp starts the XE solid roller cams out at 230/236 .522/.564 for a reason. In my opinion that truely is the range where debating hydraulic Vs. solid is a legitimate arguement.

I also vote for the 230/236 cam. Get that custom ground on a 112 lsa though. Should fit real comfortably into your new setup yet not exceed the limitations of your spring kit. I also bet your idle wont change much or any at all with the 383 and the overall street manners of the car will still be great. With that setup your gonna be banging real hard on the 500hp door. You thinking about a possible stall change? Do you run a Vig?

Its always real easy to just keep climbing the cam tree. It really comes down to what your willing to put up with for the behavior of your car. Not to mention peace of mind is always worth something as well.

Edit:
Its not exactly like the 224/230 cam is a baby cam either, you should be able to get 475hp out of it in your setup with a perfect tune. You might just want to stick with it and keep the cash in your pocket and upgrade to a crazy solid roller setup in a couple years when the mods bug comes back biting real hard again!

 

I wanted something wild, that's why I went with the cam in my sig. I also don't give a rats a$$ about streetability. I'd vote for the XE 236/242 with a custom built 112LS and 2degs of built in advance and a 110LCA.

 

No

Quote:

[i]
Edit:
Its not exactly like the 224/230 cam is a baby cam either, you should be able to get 475hp out of it in your setup with a perfect tune. You might just want to stick with it and keep the cash in your pocket and upgrade to a crazy solid roller setup in a couple years when the mods bug comes back biting real hard again!

That looks like the plan for now anyway, thanks again

 

I'm also looking to stuff a new bumpstick in my 383, since the stealth ram purchase. But all these cams you guys are talking about are roller cams? what would be similar for a hydro-flat tappet? I also don't care about emssions or gas milage. just as long as it sounds pissed off at idle and even more so at 6K, i wouldn't mind it if hauled *** either.

 

1 DwnCam

read this first...

http://www.idavette.net/hib/camcon.htm

then if your still looking for a flat tappet hydrolic the choices Id recommend are,

CROWER # 00232
http://www.crower.com/misc/m_cat.shtml

CRANE #114051
http://dab7.cranecams.com/SpecCard/D...1=Display+Card

but keep in mind youll need a programable ECU/CUSTOM CHIP,
10.5-11:1 compression, 3.73-4.11 rear gears, a 2800-3200 stall and youll need to tune it correctly., youll more than likey have some clearance issues,your going to have a good weekend toy NOT a GOOD daily driver,, don,t for an instant think its a drop it in and drive it with no tuneing deal, yes you can and most likely will see a major improvement in hp/tq but its not the ideal long trip cam/combo now that being said, getting 450hp/450tq from those cams should be possiable before the nitrous WHICH THEY ARE BOTH DESIGNED TO HANDLE WELL!

FIRST BEFORE BUYING ANY CAM HAVE A LONG TALK WITH THE MANUFACTURER ABOUT YOUR COMBO

 

my car is exactly that. a weekend cruiser. on long trips to car shows over a hundred miles she's a trailor queen. I have a lot of what you just posted and I am fully aware of the tuning issues. I was kinda hoping for somthing that would make somwhere in the 500+ range au natural, before the 200 to 600 wet direct port unit I have.

I for the moment have the stock ECU but I am willing to go to the programable system if my goal can not be met with the custum chips. I'd also like to stay with the NON roller setup, the guy who built this particular motor felt it was better for my application.

 

how much lift and duration can the stock ECM take without going crazy?

 

ITs not so much lift and duration as it is the overlap and LSA that drives sensors crazy with the pulseing vacume readings on the larger cams. with a lap top programable fuel/air flow map you can get almost any combo to run, but the stock ECU tends to get crazy at LSA much tighter than 112 or intake durations much over 220 and durations UNLESS you have a matching custom chip made,durations UNDER 210-215 are not normally a problem if the LSA is in the 112-116 range, but those cams limit your performance, youll really be better off with a lap top programable ECU, EXAMPLE (HOLLEYS 950 EFI controller)

 

So whats it going to take to make 500 + HP with the stealth ram and a commander 950? Assuming I have all the above stuff that was mentiond.

 

1 DwnCam

Its really to bad your not setup for a roller cam, your leaving power on the table by running hydro flat tap.

You will need at a minimum something close to a Comp Extreme Energy 236/242 cam to get close to 500hp. I would personally bet though that you wont see 500hp unless you get into 240+ duration due to the fact that you will be down on power compared to a roller motor.

Your gonna need some serious exhaust to keep up with that cam and juice if you decide to run it.

Whats heads do you have?

EDIT: You could always look at a Comp Nitrous HP cam if you will be running the bottle for sure. But still look at a cam that is 236 or bigger on the intake side.

 

I have hooker long tubes with the mufflex 3" offroad pipe and 4" catback.

I have edelbrock Performer RPM's that have been ported with in an inch of their life, by John beck (3rd place popular hotrodding engine masters challenge) and they flow close to 300 on the intake @600 and 200 on the exhaust.

I really don't care about emissions or fuel economy, just want to flat out haul ***. very low 12's high 11's with out the sauce.

 

1 Dwn Cam - you have any pics of your car that you can share with us?

 

sorry, nothing recent. I few months ago I tried to down load one of my features onto a floppy , but I guess i'm not computer savy enough.

 

here go's nothing.

 

thats one sweet ride you have there. I seen that car featured in camaro performers and I drooled.

 

Actually, that scanned pic if from the camaro performers feature winter 2001. The feature really does not give the car justice, it's one of those you need to see in person.

 

I know this is alittle off topic, but you said that you are running 11:1 comp. Are you doing this on pump gas? I just bought a similar setup off a guy, but I was going to do everything I could to drop a 1/2 point.

Current set up (in donor car)
forged 4030 crank 3.75' stroke.
6" rods
JE pistons (suprisingly not burnt form ping)
holley aluminum heads of some sort, I haven't called holley yet but they look like 64cc chambers with relatively big valves(of course I could be wrong).
eldelbrock single plane intake
dominator 950 (I haven't looked for the cam specs either because I KNOW it going to be something retarded).

Oh yeah it doesn't run yet mostly because I'm in the navy and I've only been home for like two days since I bought the thing.
When I did the math(based on a 64cc chamber) I got 10.98:1 compression) I live in Hawaii so getting good fresh gas is hard. Think I can get away with the compression on a 950 commander and HSR combo. The longer rod should increase piston dwell, but still I think it is to much compression for a car that going to sit in traffic.

 

its obvious some of the guys on this site need to understand the differance between static and dynamic compression ratios, and yes its one of the harder concepts to explain,
you need to understand it ! the differance between STATIC COMPRESSION RATIO AND DYNAMIC COMPRESSION RATIO
let me try and explain, the short version is that the PISTON COMPRESSES NOTHING untill BOTH VALVES ARE CLOSED, that the only compression ratio that matters to the ENGINE,since its the only comprression ratio the engine ever sees.

let me point out a few things
first look at this chart

http://www.iskycams.com/ART/techinfo/ncrank1.pdf

then lets assume your 383 sbc engine has a static compression ratio of 11:1 but youve installed this cam

http://dab7.cranecams.com/SpecCard/D...1=Display+Card

looking at the cam specs we see that the effective stroke is not the 3.75" that the static compression ratio is measured from about 2.6 inches from tdc so your true working compression is closer to 8.1:1 NOT 11:1

heres a longer more detailed explanation

http://cochise.uia.net/pkelley2/DynamicCR.html

keep in mind that you can easilly run a stattic compression of 11:1 with aluminum heads if you keep the cam timing in a range so that the DYNAMIC COMPRESSION is CLOSE TO 8:1
take the time to understand the concept,it VERY IMPORTANT

 

Actually you can push the static comp. ration and run 12.1 on 93 Octane, if you look at several other factors that affect compression. I know first hand and with the mods in my sig.

 

Grumpy,

Thanks for the info, everytime I've built a motor before I had a knowlege base (dad, friends, ect.) that usually helped me with things like this. I now live 5000 some odd miles away so I'm going this one alone. I appreciate the info. But why all the yelling? I do know that there is a difference between static and dynamic CR. I just never made the connection, hence my question. Hell I can calculate the desired CR now so cam selection is becoming alot less intimidating.

Thanks again.

 

Im not yelling Im only emphisizing the more important points