chevyman9306

iTrader: (9)

Ok so I am building my unmolested ls6 heads up to handle my cam and have picked my brain apart reading stickies and other threads trying to come up with something giving me the best performance staying on a conservative side of things...my cam specs is 241/253 108+0 .571/.572 hydraulic roller cam...I won't be spinning the motor up to 7200 rpm very often and won't see much track time (all though I have been thinking of autox a lot lately)...but I do want to know that when I want to spin it up there that my valvetrain won't float on me and that it will be durable...I think that I am going to go with some caddy racing lifters and 7.425 moly chrome push rods but I am not 2 sure on the rest...how would you guys build the heads??? I have a ls1 with stock bottom end...

batboy

iTrader: (6)

Good dual springs with titanium retainers, like Patriot Gold or similar. I'd have a good machine shop CNC port the heads and maybe add bigger valves. Then have them do a multi-angle valve job and mill a few thousands off the deck to straighten it real nice.

02*C5

iTrader: (1)

if it's not a track car
1. why are you running a cam that size.
2. are you planing to fly cut
3. have you researched PTV and cam sizes for an LS1
4. how many miles does the LS1 have
5. the LS1 is it a <98 99>
6. what other complimentary (boltons do you have or are planning on getting)
7. A4 or M6

batboy

iTrader: (6)

The cam is huge in the duration department and a tad low on the lift.

1SLwLS1

iTrader: (6)

If you're doing all that, you need lightweight valves, if they are not in there already. I would go oversize if you're doing all that and go ahead and get some bigger lightweight valves. That combined with hardened PRs, double springs, titanium seats, retainers, locks, and get Harland Sharp re-pinned stock rockers, should be good.

printmanjackson

iTrader: (1)

I'm no expert but would it not make more since to build a set of heads then have a cam spec'd for the flow of the heads?

If your looking at auto X then why would you use a cam designed for such high RPM?

Stock LS1 bottom end spinning to 7200?

Hamrdown

iTrader: (25)

That cam is way huge for a non drag car or even on some strokers plus good luck finding a tuner that won't kill you after the headache of trying to tune the drivability with that 108 lsa. For a daily driver and auto x car your going to want a good midrange. Something in the 22x or 23x will probably more suited to your needs. I mean that cam is close to the one I have in my 396 stroker and it's on big side and was designed with alot of nitrous use in mind. Give a vendor a call and they would be more than happy to design a cam suited for your combination and to meet or exceed your goals. I've used Thunder Racing for my cam and they did an excellent job on speccing everything out and really listened to what my goals were with the car.

00MaroonZ28

iTrader: (3)

Yep, that cam is waaaay to big. Seems like a track type cam that's ground for big shots of nitrous.

You'll definitely be needing ARP rod bolts if you plan on spinning it at that rpm cause the bottom end isn't gonna hold it for long. I'd plan on forged rods while you're at it. Rethink your set-up and what you plan to do with the car. Looks like you're throwing random crap together and expecting it to all work out to the car you want.

chevyman9306

iTrader: (9)

1. It is going to see some track time...I just can't be full time with the family and all
2. From what I have read you don't need to worry and flycut till a little above 600 lift...
3. I thought I did till I read everyone's response...I didn't think I was putting that big of a cam in it...thought the only thing a little crazy was the lsa but I also wanted that kind of idle so....
4. 108,xxx
5. 99
6. I was building the motor around the cam...ported ls6 oil pump, double roller timing chain, ls6 intake, 85mm maf and throttle body, ls6 heads built based on cam, ARP rod bolts and head bolts, built t-56 with stage 3 or 4 monster clutch package from tick shift, tunnel mount torque arm, 1 3/4 headers not sure on brand yet but true dual, shock tower brace, fuel system upgrades as well...
7. m6
8.Correct me if I am wrong...I really thought I have done my homework but am new to the ls1...I have built a sbc before but that was pre-lt1 days so I guess maybe something is different with these blocks that I didn't catch that is fooling my thinking when it comes to how I should be building this motor...

1SLwLS1

iTrader: (6)

I would think with that LSA some of the nitrous is going out the pipes.

The cam should be spec'ed for your goals and other mods, not the other way around. Glad you are at least doing rod bolts, your stock 99s wouldn't hold worth a crap.

The thing with PTV clearance is the fact that the piston is not static and the clearances can get a little tight with high duration cams. If the valve stays open longer, your piston is moving up towards it, and the longer it stays open, the tighter those tolerances get.

The MS4 I am running is pushing tolerances as well. I have a lot more lift, but you have 11 more degrees of exhaust duration than my cam and on my exhaust duration, my lift is closer to yours at max.

I would definitely be checking PTV with this setup, and double, and triple, and quadruple check it.

02*C5

iTrader: (1)

^^^

What I was going to say exactly. The LS1 engines are very tight in clearances thus the motor is very efficient at what it does. Lift has little to do with fly cutting on these engines. It is more on lobe separation & duration. Like stated above the longer your valves stay open the more likely hood you will have to fly cut specially if you are running over sized valves. I would contact Pat G, Predator Z or Ed Curtis and ask them to help you out with a head and cam selection. Those guys are at the top of the game right now and they can get you to where you are trying to get.

Also please don't think we are trying to jump on you, we are trying to make sure you don't end up like many who are given advice and then a few months later come on the board talking that they blew their engine, or tore up their valve train etc because they wanted to do it their way.


Advice is free not taking advice can usually get expensive.

good luck.

hammertime

iTrader: (1)

1. Your cam selection is more agressive than the TRex cam (31* overlap). It will not be pleasant to drive below 2500rpms.
2. Lift is NOT the primary determinant for PTV, duration is, and that cam will not leave any margin at all. Plan on cutting clearance for the intake and exhaust.
3. That kind of idle will cost you your streetability in a 346ci car. You'll probably need a speed density tune to make it idle and handle transitions well.
4. 108,000 is fine for H/C, but 7,200rpms on a stock bottom end with only rod bolts may be pushing your luck.
5.
6. Perhaps you should phone some sponsors here, or better yet, hook up with one of the experts here on the forum and see what they recommend for what you want to do. You can spin a cam with 10* less duration to 7200 if the VE's are right.
7. With an M6, you'll need 4.10 to 4.56 gears to work well with that kind of cam.
8. That kind of build is fine for a carbureted SBC that you want to do some hardcore cruising or tack to the track on a regular basis. It takes a lot of effort to make that kind of cam work with EFI, and it will still be lucky to get on cam just driving around.

Pat G put down 459/410 with a 224/228 cam that had 6 degrees overlap. After an upgrade he made 508/445 with a 238/242 cam that had 16 degrees overlap. If you aren't ready for a 90% track car that is mostly devoid of street manners, you should probably look somewhere in between.

chevyman9306

iTrader: (9)

That must be the link that is throwing me for a loop because I had a pre lt1 68 Impala that had a .550ish lift cam but admittingly don't remember the lsa the cam had...I loved the sound and streetability was still really good for my taste...though it was an automatic so take it for what it's worth...

Also why would my rear end gears matter for which cam I was running??? IMO for not understanding this I have seen a car with 2.70 gears in the rear smoke the tires off...car was making over 1000hp on pump...or so is claimed...

1SLwLS1

iTrader: (6)

With such higher duration, your powerband is going to be up top, the gears are there to get you to your powerband quicker.

chevyman9306

iTrader: (9)

Ok now that makes sense...lol except I am beginning to think that I need a different cam to achieve what I want even though I think I would have more fun with this cam

SOMbitch

iTrader: (8)

That cam would suck on 346 cubes even it would clear. It would have no lowend torque and would make peak power past the rpm range your motor can spin and stay together and buck and surge at low rpm. FWIW lift has very little to do with PTV as max lift occurs when the piston is near bottom dead center. Duration,LSA and advance have more effect on ptv.

If you want a max effort cam that will clear w/o flycutting look at a TRex, MS4,LGx5etc...These are strip cams that need gears. If you autoX you will want a torque cam that pulls mid to upper rpm's so a high 220/low230 would be nice for that and still make good topend power. My little cam peaks at 6200 but loses only 4hp at 6500 so it carries well...

Also build your motor around you heads not your cam. The ultimate potential of your motor lies in your heads ability to get air in and get air out. Pick the supporting compenets to help the heads maximize that potential. 243's are good start so see what works well with them. That LS6 IM will fall off after 6300 so as an example it doesn't match your free reving cam. Pick a combo where everything complements each componets strong point....

Hope this helps and with enough research you will have a strong setup

printmanjackson

iTrader: (1)

^ very well stated

00MaroonZ28

iTrader: (3)

+1. Good post. Explains it all. You'd hate to drive that cam on the street.

chevyman9306

iTrader: (9)

Wow this is very helpful to hear as I was trying to build it in reverse but I am starting to understand why to build the other way around...also decided maybe waiting one more season to cam the car might be a better idea so that I can do more research on the ls1 as I am realizing that I don't know as much as I thought I knew...so for now I think I will build the tranny while it's out of the car, put the 243's on it, ls6 intake and few minor things and have fun for the summer and collect a few parts on the way for the real build next winter

Well at least I didn't almost mess up big time...whew...Thanks to all for the advice!!!

94TRANS

iTrader: (39)

that cam is wayyyy to big for what you described using the car for, thats almost a strict track cam and kind of wierd specs, the lift seems a bit low for the duration...