camaro350tpi

hi all! need good advice for my cam choice here ! engine spec i was running : 383 4.04 over 10.7 CR 113 corvette head heavy ported cfm at .600 should be 246/196 . holley stealth ram intake with xfi280 cam shaft. i never ran a dyno session but best 1/4 time ived made was 12.2 sec 1.7 sec 60ft. man trans tko600. So now i have to buy another cam because of lifter faillure.... ived contact guys from comp cam and crower :

was running xfi 280 dur: 280/288 at 0.50 232/236 lift .576/.570 113lsa/109ic

they said:
crower 00668 : 277/286 at 0.50 225/232 lift .572/.587 110lsa/106ica

comp cam xr294hr :dur:294/300 at0.50 242/248 lift .576/.600 regrind at 112lsa for efi should make more top end and mid-range power with a stronger overall increase in performance like he said..

i used dd2000 and engine analyser but still confuse , the best cam in dd2000 is the crower more torque and hp but in engine analyser best cam will be the xr294 .. ived entered the same flow chart that i found for my heads in both progs. maybe some one can help me here thanks !

Orr89RocZ

iTrader: (20)

Depends what you want to do with the car. Xfi is a decent match for that combo but needs good lifters and stiff valvesprings to work. Ls7 lifters and patriot extreme gold springs or similar or one of the stiff pac beehives could work.

Crower is tad smaller but tighter lsa, should make good midrange power. Still tuneable even tho on 110 lsa.

Comp cam will likely run the fastest 1/4 mile but really is a big cam and will pull rpm. Heads wont really support all the cam could offer but cam will continue to hold hp beyond peak, requiring a shift point way over 6500. Basically same thing that happens on lt1 cam only cars. They cam up big and make most power but sacrifice alot of lower rpm power and are forced to rev real high, 6500+. Rough on street but car runs hard if everything else suspension wise and gears are setup for it.

Smaller cam by crower will likely be smoother driving and more snappy, better match for heads rpm range but track car will favor the bigger cam. Xfi280 is between the 2 and would be my choice for a shelf grind but its abit harder on springs. The big comp needs good stiff springs too for the higher rpms it wants to pull.

camaro350tpi

yeah ived read a lots about the xfi cam, i was running this cam last summer, with manley spring rated to Open Pressure lbs to 334 lbs and i think comp cam recommend 367 lbs open press but it was running strong to easy 6000 rpm and shift about 6200rpm , MOSTLY i run the car on strip not realy for driving so i could try xr294 i want the fastest 1/4 miles i can make with my combo. maybe i need stiffer spring too what you think?

Orr89RocZ

iTrader: (20)

Could actually try the 288hr on a 110 lsa. Its a 236/242 grind. With 1.6's it would run well.

These cams need atleast 375-400 lbs open pressure and 140-160 lbs seat. Xfi i would use 150-170 lbs seat and 400-425 open depending on valvetrain weight. I would expect the 230/236 xfi to be near done by 6200 on that setup but still needs more spring. My friend ran 320 lb open springs and it floated by 5700, very similar heads. 2.02 valves afr 190 old school heads.

You would run faster with right springs with that 280xfi no doubt

camaro350tpi

there are a lots of camshaft... its hard to choose the right one, guess ill stick with comp cam brand now i have to choose between xfi280or xr288 maybe xr292 ...

TPI-Formula350-

I run the 280xfi and like it a lot...I use the comp magnum lifter, as far as springs. I use the comp 26918 beehive springs which comp calls for with that cam. I'm sure other lifters and springs will work but I just used what comp matched to the cam.

what mph did you run on that 12.2 pass?

David 91RS/Z28

What exhaust setup?

IROCThe5.7L

Comp recommended the same cam for my 427 with AFR 220's. It's not running yet though. Hopefully by spring.

TPI-Formula350-

thats going to be real nice in that clean IROC

camaro350tpi

your setup it bigger than mine i think he overcam my setup ...

camaro350tpi

114mph

camaro350tpi

i have hedman 1 5/8 shorty headers with a 3 inch cut out when i drag race

Orr89RocZ

iTrader: (20)

114 is about right for that cam and those heads. To get much more you will have to go bit bigger and more aggressive and rev high and gear up its over cammed with the 294 cam. I'd lean closer towards the 288 or a cam similar. Abit more intake lift if you can. Custom grind is the way to go

One of the fastest lt1 cam only cars with less flowing heads than yours went deep 11's with a big mid higher 230's deg joe overton custom grind. Hes not doing cams anymore i do not think but others can set you up

Plus long tubes and 1 3/4 headers will help. With shorties you are exhaust limited. Cc306 type grind could work too

camaro350tpi

i found an other one dont know the brand isky ISK-201282294

Duration 282/294, 0.05 234/246 Lift .530/.550 110lsa

camaro350tpi

howards cam 181815-12 290/298 .050 237/245 lift .560/.560 1.5 rr 112lsa 108 icl

Orr89RocZ

iTrader: (20)

Look up lunati voodoo cams around same durations. Gm 847 cam as well. All known to work well in heads like those. I like abit more aggressive lobe on heads that are a slight restriction. Seems to work well from what i seen

IROCThe5.7L

I sure hope so. I've been following your build for a while. The new engine seems stout.

TTOP350

iTrader: (8)

Heads and exhaust are going to hold you back.

Orr89RocZ

iTrader: (20)

I dont know if i told you but my 246/252 .640" 113 lsa cam works fantastic in my 400. Much tamer driving than i expected. In a 427 it would be even better but it is abit low on vaccuum. Might be with the large 245cc heads. Air speed is abit low but i could throw more timing at it. Its already at 30 deg tho

cuisinartvette

Need more specs from those cams like the seat timing to really tell.
Always loved the way Iskys ran

With Orr....weaker head /quicker seat timing helps crutch things some it seems to make sense. As said make sure you spring that head just right...even another 10lbs over recommended wont hurt anything

86LG4Bird

iTrader: (1)

As long as you're willing to invest in a stout valvetrain, you'll do well with a custom cam from these folks: www.advancedinduction.com
I'm running a 228/234/108, .613/.613 HR from them with their ported LT1 heads on my 350 in the 3800 lb ImpalaSS and have run 10.9 @ 122 NA. I'm running the bigblock style beehive springs. They've told me not to expect more than 15,000 miles from the springs with that cam though. I'm nowhere near that mileage but have about 180 passes on them and it pulls strong to the stock PCM 7100 rpm cutoff.
Don't get me wrong; they DO NOT sell cams that are overly harsh on valvetrains. They're just totally honest telling you what to expect, whereas some of the other places spec'ing more aggressive custom cams are not.

camaro350tpi

how much hp you get of that 350 NA to make 10.9 1/4 miles?? hard to beleve

camaro350tpi

i found another one
lunati 54756LUN 232/242 290/300 .510/.525 110lsa/106cl

or LUN-20080722 231/239 282/290 .535/.550 110lsa

solid roller LUN-40120731 237/243 267/273 .566/.578 110lsa

86LG4Bird

iTrader: (1)

420 at the wheels through an unlocked 8" converter.

Anti-Venom

Your floating the crap out of the valves. Hence your beaten and dead lifter/s. The XFI cam's are designed for the new beehives, 8mm valves, and lighter rockers that are out now. If your running one on 113's with std 11/32 guides and std springs, your running more tech in the cam grind than you have heads to handle.

Honestly the first thing you need to do is junk those 1-5/8"s headers. They are too small for a built 350 let alone a stroker. The best cam in the world won't make you run faster if your hitting a brick wall restriction in the rest of your setup and floating valves. Even on a mild 350 I've never noticed 3/4"s give up much torque over the 5/8's and am curious why anyone ever runs them on anything bigger than a 305.

You've got some miss-matched parts going on here. A smaller cam will give you much better drivability, broader torque, and will be a better match to your heads and possibly the rest of your car.

I'm going to assume by your 12.2 et, that your near stock curb weight, and 3.23's? You never did mention if your car has any weight reduction, or what gear your runnin? I'm thinking you should stick conservativly around 220-230 duration and 112-113 LSA.

Lingenfelter's model 383 build was using ported 113's, Superram, his outdated219 single pattern cam, and 1- 3/4's. Put out 442hp at 5200, and 481lbft at 4500. and was only at .525 max lift.

This should be a good indication that .572-.600 is too much lift and you should have better heads for these cam's that are being recommended.

Orr89RocZ

iTrader: (20)

Keep in mind this is for strip. Small cam is street friendly but not going to get quickest ET's imo. I would not switch cams to something smaller than current duration of 230 and would keep intake lift up over .550". The heads are flowing to .600 and i assume port work was well done. You will need valvetrain work. Good springs for the lobe but it will produce power. Xfi custom ordered on a 109-110 lsa would do well but needs atleast 150-160 lbs seat pressure and 400 open imo

Model this like a mild ported LT1 engine and you will do well. AI, Lloyd Elliott, Bret Bauer, bullet cams, cammotion, mike jones will set you up well for a custom grind.

Better springs with current cam would wake up the motor as mentioned, it was floating valves

Anti-Venom

I completely agree with you Orr in regards to specing his cam for a "strip only" application. I have a feeling though, his car's not exactly setup to be a dedicated drag car yet. Especially looking back at his post history. He doesn't even have the right headers on it yet.

My theory is, more can be gained now with the smaller cam, and as his car progress's, a new larger cam's a drop in the bucket later on. Nearest I can tell he's still running a BW rear end.

I also always error on the side of being skeptical on most home ported heads. Especially with the term "hogged out" being thrown around. Few people cut into a head with a flowbench at their disposal, or have the experience to do more than light porting w/o doing more harm than good. He also didn't say they were flowing 246/196, he said "should flow". But that's an unkown at this point, He could very well have had experienced work done to them.

Orr89RocZ

iTrader: (20)

Valid points. I have been a build engine first while you can and then setup the car to work kind of guy. Once you know what the engine is gonna do for power and rpms, do everything else to match. Figured it needs a new cam now might as well buy it once and deal with it later. Sorta like my friends build. Xfi280 on stock stall stock trans and little gear in it. Eventuall got around to doing gears, tranny rebuild plus converter and got the combo to work much better.

All in how you want to approach it. He does need better headers and enough gear to make it work best.

86LG4Bird

iTrader: (1)

I agree completely. Reading between the lines tells me it's gonna be a lot of work and time until a larger cam would no longer hamper the car's performance.

camaro350tpi

hi thanks for reply , stock curb weight and my rear ends is a 3.73 , tranny is tko600, i know the headers are small but i didnt found 1-3/4 shorties... long headers will be best but didnt have anought ground clearence so... but i need another cam my xfi280 is no good anymore if there a better cam them thise one for my setup ill choose another one

cuisinartvette

If you go shorties keep an eye on collector ID
big primary does you no good if they cant get through a 3" collector imo

hate that term. soon as I hear it my ears usually dont listen to much else they have to say.

On should flow..btdt. get them to a flow bench youll be pleasantly surprised or more times than not be taking the grinder to them some more lol.

Only a seasoned pro can take a peek and get a rough guess.
Otherwise youre shooting in the dark

Doesnt cost much to have at least 1 cyl flowed to get an idea where youre at.

camaro350tpi

so ived use engine analyser several time with many cam gring that i found and the best overall cam was the lunati
LUN-20080722 231/239 282/290 .535/.550 110lsa
there more torque all the way of the power band peak at 498 lbs at 4250 rpm and 443hp at 5000 rpm .

the best peak hp that i can get was with the xr294hr10 but only make 448 hp at 5000 and about 15 lbs/tq less all the way of the powerband but peak at 497lbs/tq at 4500rpm

i think ill do better time with the lunati 231/239 282/290 .535/.550 110lsa

camaro350tpi

just for info the lt1 cam fit on gen1 roller block ? we just have to cut the dool pin right?

Anti-Venom

Yes sir.

camaro350tpi

did someone had issues with the spider plate and dog bone ? cause the reason that i have to change my cam is due to bend spider arm and the dog bone went free so one lifter turn a side and has grind the lob down a little .. i dont know if i should buy linked lifter or stay with the oe system... dont know what happend here, my engine builder said everething was right and it was just a bad luck.. only 2k i had on this engine..

camaro350tpi

hi orr , i thinks ill go with a single patern cam, the I/E ratio of those 113 heads are about 80% and i also run on open headers . ill take a little more duration on the intake and more lift to get little more top **** point for better ET so i found that cam and i want to know what you think about it
howard cam 180635-10 290/290 237/237 .050 lift .595/.595 with 1.6 RR 110lsa 106 icl
ill get new spring too no less than 400lbs open...

Orr89RocZ

iTrader: (20)

I like that cam. OEM dogbones should work and should not bend unless bolt backed out. Make sure its torqued down and locktighted. Good springs about 400 open maybe abit more pressure. 155-175 seat pressure. I ran similar cam lobe, 286 / 230 .603 on a 109 lsa. 165lbs seat, 412 open pressure double springs. Worked great to 7K rpms.

camaro350tpi

orr , i just find out with my engine builder that i have -26cc dish piston , not -16 cc that i suppose to have. he made a mistake when ordering something like that so my compression is not 10.7 like i was thinking but 9.6 Cr so my dcr with the 237/237 , 290/290 is 7.32 dcr and the cam spec said 10.00 CR min but i have 9.6cr do you think that cam will not work well with this static compression?

DeltaElite121

Just so you know - Lunati charges the same price for a shelf cam as they do for a custom cam. I talked to Steve the other day about grinding a solid roller profile for me and he said there is zero difference in price (I wanted to tweak a shelf cam they had, essentially).

Just a thought if you've got different desires with what you're doing.

camaro350tpi

good to know , ill call lunati tomorrow thanks for the info

Orr89RocZ

iTrader: (20)

Cam will be alittle more lazy with that compression but still can work. You could also get a custom grind to trap alittle more compression in the cylinders to keep dcr up. Could try lunati, maybe Mike Jones as he has done many low comp type deals that need cylinder pressure.

Nelz

Um...if you're going to call Lunati, David Vizard (yes, that David Vizard) has a custom line of cams available through Lunati that he wrote about in his How to make Max Chevy Horsepower book. For maximum street, on a 383 hydraulic roller block, he recommended part number DV290-06HRH. You have to let them know if you have the late model post 87 block otherwise you're going to get a retro fit hydraulic roller cam. Specs are: 290ADV. 239@0.50 for intake and exhuast on a 106 LSA (It's a single pattern cam.) .550 lift with 1.5 rockers, 0.587 with 1.6 rockers. His "street/strip" cam is DV294-06HRH. 294ADV. 243@0.50. 0.559 lift with 1.5, 0.597 w/ 1.6. His "REAL RACE" cam is DV302-06HRH. 302 ADV. 251@0.5. 0.565 w/ 1.5, 0.603 w/ 1.6. All single pattern and on 106LSA for a 383. If you're calling Lunati, you can ask them about it.

DeltaElite121

Mike has his ways with making small cams go fast. Dude definitely knows his stuff. That's who I'd go to if I was starting off in the "shallow end" of cams.

Orr89RocZ

iTrader: (20)

Problem with David's tight lsa is its gonna start getting very low on vacuum and abit more difficult to tune. I ran 230/245 .603/.613 on a 109 and it worked great and tuned well. Choppy idle and brakes worked ok. 106 lsa and 239 deg is alot more overlap. Doable but not sure its worth the hasle. Mine never bucked or surged during low speed hill climbs but going much more overlap could start to become a problem

Nelz

http://www.popularhotrodding.com/tec...s/viewall.html

LSA is a function of desired overlap. Since he asked for a race Cam, vacuum is not as much of an issue but he would have had to time for the new cam anyway. If he's running EZ EFI with the HSR then he would have even had to do that!

Nelz

Also the LSA was for a 383. For a 350 a 108 LSA would be correct.

Orr89RocZ

iTrader: (20)

Yeah true, vacuum isnt as much a factor for strip but i assumed he would be driving to track or on the street occassionally where brakes could be more of a concern. Just a thought. And if it is stock ecm tuned, its likely it can work with that lsa but just abit more work. Self tuning software would have a hard time with it at low speeds. high overlap fools o2 sensors. Not sure its worth the effort for minimal gains. I dont see lsa change alone making substantial differences in overall power curve. Two cams should be close imo but i'd love to see the test. I have seen others where big swing in lsa didnt do much. Both good suggestions.

Nelz

Formula for calculating overlap:

2) If the seat to seat opening and closing times are not known, the overlap can be calculated using the advertised duration and the Lobe Separation Angle (LSA). This formula works for both single and dual pattern cams.

Add the intake and exhaust adv durations
Divide the results by 4
Subtract the LSA
Multiply the results by 2

Using the example cam above:
268+280=548
548/4=137
137-110=27
27*2=54
The overlap is 54º

http://members.uia.net/pkelley2/Overlap.html


Here's another example:
Comp Cams XE294H
Adv Dur: int 294º, exh 306º
110 LSA, 106 ILC (4º advance)
Valve timing @ .006"
Int opens @ 41º BTDC
Int closes @ 73º ABDC
Exh opens @ 87º BBDC
Exh closes @ 39º ATDC

Adding the int open and exh close times (41+39) the overlap is 80º

Using the formula above:
294+306=600
600/4=150
150-110=40
40*2=80
The overlap is 80º

DeltaElite121

OR

Google>overlap calculator>done.

Nelz

You still need to understand the math behind why LSA affects overlap. Anyways, I was looking at the David Vizard Chart again from his book. With 10:5 compression, the biggest cam that will work is the DV294-06HRH. That's the street strip cam. The real race cam requires 12:1 compression to function.

David Vizard matched his cams to the minimum required Compression ratio's too. So, if you haven't bought a cam yet, ask Lunati for DV294-06HRH on a post 87 factory roller block.

Ask about valvetrain mods needed, but David Vizard said the COMP 26918 springs are what is needed (beehive) or PAC equivalent. And the spider system will work, however there's a special procedure described on how to use the stock hydraulic roller lifters in the book. Or you can get the COMP special lifters for hydraulic roller lifters. How high are you going to rev this motor?