Well I've got some more questions for the masses.

I recently purchessed a L98 cam (10066049) from Justin Orr here on the boards and I am once again torn about what I want to do. Just for clarity here are the cam specs for both cams and what they will be with my 1.6 rockers.......

10066049 207/213 - .415/.430 117 LSA L98 cam

10243779 191/196 - .418/430 111 LSA L31 or B-body LT1 cam


Now with 1.6 rockers......

10066049 210/216 - .443/.459 117 LSA L98 cam

10243779 194/199 - .446/.459 111 LSA L31 or B-body LT1 cam


From what I believe the duration usually goes up by three numbers when 1.6's are added.

Now here's why I haven't used a LT1 cam. I don't have the money for another set of 1.5 rockers so for now I'm trying to keep the lifts moderate.

What cam should offer the best performance? I know I'll have more bottom end torque with the L31 but I'll have more top end with the L98. From the research I have done I will lose some bottom end with the L98. And The L31 will be easier to tune in.With a S10 converter I should be ok with the L98 but I'm still a novice at tuning and I don't want to get in over my head just yet?

What should I use?

 

What is the intended usage for the engine?

Around town, you'll stay under 3500 rpms anyways so, don't give up your torque.

If you are going for *****-out, high rpm, WOT..Go for higher rpm horsepower.

 

For me tese cars really miss power wenn overtaking on the highway, I would opt for the top end power.

 

For the most part it will be use around town. I live in a really small town. so I need the bottom end torque. I have a 96 silverado with the same cam and it seems to poop out around 4500 to 5000 rpms.

 

My cam is pretty similar to the L98 (206/216, on a narrower LSA) I have plentry of torque, None of these cams are big by any means, remeber from the factory, the G92 LB9's got the L98 camshaft, and no one complains about their torque.

If you are into tuning at all, I would say go even bigger than either of those. The L31 is small enough, it almost isn't worth upgrading to, I would go L98 or bigger. You will have more then enough torque.

To put it in perspective, I have 250lbs/ft of torque in a straight line from 1500 - 4100 RPM, it never moves from 250 the entire way across the board, and my cam is on a 112 LSA, with the 117 LSA of the L98 cam, it will be an even broader curve. I would honestly look for something in the 212* intake range, and get it on like a 114, and call it a day. It will be tunable, drivable, it will pull from any RPM you want it to.

 

I'm trying to use what I have for now. As I said earlier I don't have the money for 1.5 rockers, so I'm trying to keep the lifts down. So you're saying that I'd have more "usable" power with the L98 cam? If I use an S-10 (L35) converter would that help with the loss of down low torque?

 

I'm saying your not going to lose torque at all. I have 250ft/lbs of torque at 1500 RPM. Even a stock converter will flash to that when you go from a stop.

I like the specs on the L98 better than I do on the L31 cam, there is SO little duration on that cam. Either way, changing cam, means your are tuning. Both of them should be pretty easy to tune though, the L98 being on such a huge LSA will help in the tuning process.

I guess the big question is what is your HP goal? If you only want 200hp, then use the smaller cam, if you want 240hp, use the bigger cam. If you want 300hp, you need to save some money, and come up with the $300 for better cam.

 

I'm experimenting for now. When I get better with tuning I already have a ZZ4 heads and cam set here ready to go. I plan on getting a ZZ4 intake to round out the equation. I figure that will get me to that iillustrious 300 hp all us 305 tbi guys are after.

 

I agree with John, the larger of the two will work well. If you did not have the 3.42's it might be different. I ran the LT4 with a 3.08 and had plenty of torque from what I remember and I didn't have it tuned. Pre-EBL. Around 2000 or so. So no worries....

 

Just for the sake of asking what would my powerbands be with each cam? Anybody have a desktop dyno they could do for me? I figure if I could get a rough estimate I can plan other mods.

 

Don't forget that a stock Vortec 305 with restrictive intake and exhaust and the small Vortec cam pushed out 225hp. A 250hp 305 with the Vortec cam is not unreasonable with a good intake and exhaust.

 

I ran a 210/216 @.05 115 LSA for a year. MAX HP was 5100 rpms on dyno exactly as Crane said. I will guess MAX TQ was about 3200-3400 I cant remember. But that was a 350 cid. I would think a smaller engine would be 200 rpms higher?

 

so how did the engine feel in the midrange? I just trying to get a basis for ALL AROUND power.

 

compared to stock nothing was lost(manual trans) in TQ or general drivability. swapped in a 224/230@.05 at 114 LSA and yes I lost midrange compared to prior cam. new cam peak TQ is probably 4000 rpms. Peak HP 5800-6000. But again I have a 350.

 

The L98 cam only made 240Hp stock when used in a 350

 

with a crappy factory tune, and TPI limiting the upper RPM's. Your point?

I've seen enough 305's with a good tune, and HSR's, or a good carb intake put more than 220hp to the wheels with that cam.

 

I've finally come up with a plan due to some racing I did last night and I guess some upper rpm power is needed tell me what this combo sounds like


This L98 cam with my 1.6 rockers
210/216 -.443/.459 117 LSA L98 cam
S10 converter
some home ported swirlies with backcut valves,Maybe some 1.94 valves
manley 22410-16 springs
and 23652-16 retainers
12371043 single roller chain
everything else in my sig.

what do you guys think?

 

The only thing I wouldn't do there is 1.94 intake valves. I'd stick with 1.84's in a 305. I'd still port 'em out good, and throw in backcut valves.
With 1.84's you'll have less shrouding and you can still get your heads to flow more then enough for a healthy 305. Besides, 1.84 valves in a 305 is the equivalent of running 2.02's in a 350, you don't need to go bigger.

Maybe even get your heads milled a bit for compression, I'm not sure what compression you're running right now, but get it up around 9.5:1 and you'll be golden.

 

Did I see in one of your posts above that you have a ZZ4 cam?
If so, that is DEFINTELY preferable over either the L31 or L98 cams.
The power potential of the ZZ4 is so much greater; the extra effort to tune it will be well worth it.

 

my stock vortec with l31 cam is put over 300 to the flywheel and over 250 to the tire. can a l98 cam do that?

 

Same here. The stock L31 in my my pickup with longtubes and a PCMforLess tune put 254 hp to the wheels. Power peak was at 4600 rpm.
However, I'd go for the L98 cam in a lighter vehicle like a 3rd gen.

 

Just curious if you're sure about the data posted for the 10243779 cam. I thought the numbers were higher.

 

It is a tiny pathetic grind with low lift, 5° advance built in and a tight 111° lsa. Its all about making off-idle torque.

 

Dur doesn't change 3 numbers, it does move a tad but not near that much. The lift does go up .3ish with a .1 increase in your rocker.

The reason the L31 makes more power is because of the better heads/intake.
Using the vortec heads on a 350 with L98 cam and it will make more power over a bigger rpm range, esp with a bigger intake.

Ditch the swirlys, Vortec heads/base, use your hot cam and a 1.6 rocker. Enjoy

 

wow talk about thread resurrection lol, I'm not even in the tbi world anymore. (well kinda, I am using a 454 tbi base for my single plane efi LT383 lol) I didn't use either of these two cams with my 305. I jumped all the way up to a ZZ4 cam with damn good results. The ported ZZ4's and cam are going onto my 91 L98 car with a stealth ram lol.

 

Holy cr-ap! I normally look at the dates but for some reason, I didn't ! haha

 

Wow I did not notice either...Atleast he searched for the info.

 

I always try and search. I rarely have to ask a question, but it seems like the more I search the more variance I get on the LT1 numbers.

 

ahhhh....so I'm glad my advice panned out for you! (post 19)

 

May be due to tha motor being used in several platforms. My friend had an LT1 motor in his Buick Roadmaster. I am currently running a blend of LT1 and LT4 for SA. I pretty much split the difference in tha SA tables. No KC's so far. Edelbrock RPM heads(2007 release CNC).