Hi guys. I'm in the middle of putting my new L98 together, and I'm trying to decide which cam to stick in it before buttoning everything up. I'm eventually going to be running a custom prom, but I'd like to start out with the stock 89 MAF 5.7 prom. I guess I should give some info on the new motor first. L98 350 bored .030 over, KB hyper pistons, approx 9.7:1 comp., ported 083 heads w/1.5 ratio roller rockers, balanced rotating assm., Accel Superram base manifold, siamesed SLP runners, fully ported plenum, 52mm TB, and Hooker 2055's w/3" catback. I've also got the Superram plenum/runners, but I want to use the SLP runners/ported factory plenum to start out with. I have a ZZ4 cam sitting here, which I know will work just fine with the factory chip, but I also have a Comp cam that I think will suit the Superram setup better once I put it on. I guess what I want to know is if you guys think the Comp cam will work ok with the stock prom or not. I'll be running it with an 89 165 MAF ecm. I'd hate to have to change the cam later with the motor in the car if I can just put it in now. Here's the specs on the Comp cam. I don't think the lift will be a problem, but I'm wondering if the duration is going to be too much. As stated before, I'll eventually go with a custom prom once the Superram is installed, but I want to use the stock prom for now. Any opinions you guys can give me would be greatly appreciated! Brand: COMP Cams
Product Line: COMP Cams Xtreme Energy Camshafts
Part Type: Camshafts
Cam Style: Hydraulic roller tappet
Basic Operating RPM Range: 1,800-5,800
Intake Duration at 050 inch Lift: 224
Exhaust Duration at 050 inch Lift: 230
Duration at 050 inch Lift: 224 int./230 exh.
Advertised Intake Duration: 276
Advertised Exhaust Duration: 281
Advertised Duration: 276 int./281 exh.
Intake Valve Lift with Factory Rocker Arm Ratio: 0.503 in.
Exhaust Valve Lift with Factory Rocker Arm Ratio: 0.510 in.
Valve Lift with Factory Rocker Arm Ratio: 0.503 int./0.510 exh. lift
Lobe Separation (degrees): 112
Intake Valve Lash: 0.000 in.
Exhaust Valve Lash: 0.000 in.
Computer Controlled Compatible: No
Grind Number: CS XR276HR-12
Quantity: Sold individually.

Camshaft, Hydraulic Roller Tappet, Advertised Duration 276/281, Lift .503/.510, Chevy, Small Block, Each

Just for reference, here's the specs on the ZZ4: Lift-.474 intake, .510 exhaust; Duration @.050- 208 intake, 221 exhaust; 112 deg. lobe separation.

 

Go with the Comp cam. It will build power up high, and it looks like that's what you are building for.

 

[Computer Controlled Compatible: No]

Enough said!

 

Ok, simple enough reply. If there's absolutely no way it'll run on the stock prom, maybe I'll go ahead and have a mail order one burnt for now until I can get all the equipment to do my own down the road. So do you guys think a custom prom will be a must for the Comp cam then?

 

Yep.

 

If you go to Comp's web site, you may find that the XR276HR, part number 08-503-8, is listed as a computer compatible camshaft. And it does call for a modified PROM.

http://www.compperformancegroupstore...Category_Code=

 

Hey thanks for the link mnorton. I received a PM from a member who's fairly knowledgeable with MAF systems, and he said it will run on the stock chip, but probably not very well. I did a marathon reading session on the DIY Prom forum last night. Went to work on 3 hours of sleep today! After all the reading, I pretty much have to agree that it would probably run, but definitely not optimal. I think I'm going to take a step back for now and just go with the ZZ4 cam, along with the Accel base, SLP runners, and ported plenum. I'll just stick the Comp cam and the Superram plenum/runners on the shelf for now. This is the first TPI motor I've attempted to play around with, so I think that would probably be my best approach until I get a better feel for what I'm doing. Besides, I'll see if I can pony up the cash for a set of AFR 195's, and my chip burning equipment in the meantime as well. With summer right around the corner, I want to get that new motor off the stand in the garage, and in the car! I've been spoiled up until now with my old-school, carbed, 4-speed 69 Camaro. You can throw just about any cam in that car without a ton of guesswork. Don't have to worry about stall speed, injector size, or computer compatibility in that baby!

 

zz4 and a set of stock vortecs!
the headswill work up to a 520 lift

 

Huh, that's interesting to hear. Didn't know the vortecs were good for that much lift in stock form. I've already had my 083's reworked with better springs/retainers and positive seals to handle the ZZ4 though. Besides that, I'm done buying intakes for a while! Lol. I'd have to plunk down another $350-$400 for the Scoggin-Dickey vortec base. I paid about $850 for the complete Superram setup, and another $250 for the SLP runners/ported plenum. Hmmm, that makes me ponder something else. I wonder if the SDPC vortec tpi base has larger ports like the Accel/Edelbrock bases do? I kinda view vortecs as the next step up from iron L98's. They're a nice upgrade, but I think I'm going to stick with the ported/reworked 083's until I can afford to go all out with AFR's.

 

Apperantly the ZZ4 cam is not for a computer comtrolled vehicle . Mine started right up ( clip in my sig) ...that was a 350 ...with a 305 Prom ...and 350 injecors ...thing ran great !


Just assumeing here ( others can straighten this out for me) BUT..... i feal any cam with at least 112LSA ...you should be good to go ( unless you got some rediculas overlap or duration ...)

 

Well, after hours and hours of reading old posts and asking lots of other MAF guys which cams they've used with good results, I ended up opting for a third cam. I decided I'm going to use the Comp Xtreme Energy cam# 08-502-8 (218/224 duration @.050, 495/502 lift, 112 LSA). It's basically one step down from the other Comp cam I have. From what I've found in my research over the last week, I figure this cam ought to work fairly well with the intake setup I'm starting out with, and should work even better once I get the Superram and aftermarket heads on. I'm pretty sure it'll run ok with stock programming until I get a custom prom after reading what other MAF TPI guys have run with a fair amount of success. Wish me luck guys!

 

that is the same cam i picked up about a month ago, than found out the heads i planned on using needed to much work, lol, so now i am looking for a decent set of heads.

 

I know what you mean on the heads. Even though I've ported them quite well, I'm sure my setup won't be optimal with the 083 iron heads. But the word "optimal" is really the key thing isn't it? I'm sure they'll get the job done for now. Hell, I'm running an even bigger flat tappet cam in my other car with only ported 2.02/1.60, 462 casting fuelies, and it screams all the way to 6K. I'm sure it would do more with a good set of aftermarket heads, but.....

 

vortech heads in stock trim are only good for .480 lift not .520, modified vortech heads with ZZ4 springs and retainers and machine work for the larger springs will allow .520 lift but come in at 330-370 a head from scoggin. how much is that comp cam ur gona be running? and why wouldnt u go with the HOT CAM, the duration is pretty close and lift comes in at .492/.492 with 1.5s and is only 200$, if i were to upgrade my stock L98 heads with comp PN 981 springs and retainers will i be able to run the HOT CAM with my L98 heads? or wats a good cheap cam for a L98 head and HSR combo (eventually gona be a 383)

 

Yeah, I thought stock vortecs being able to handle .520 lift sounded fishy too, so I looked into it, and you're correct. In stock form, they're only good to .480 lift. I'm sure you'd have no problem running the hot cam if you went with the 981 springs w/matching retainers. The Comp 502 cam that I decided to go with has .495 lift on the intake, and .503 lift on the exhaust with 1.5 rockers. Duration is 218/224 w/112 LSA. And yeah, it's expensive if you buy it from Summit ($256.00). I got lucky though, and found a guy who had a brand new one up for auction on ebay that only lives about 50 miles from me. I talked him into ending the auction, and selling it to me outright for $175. The hot cam's not a bad choice either, but what appealed to me about the Comp cam is how quick the ramps are. This is supposed to give you more power throughout the whole rpm range, or "under the curve" as they say. I was going to use the ZZ4 cam until I read that the ramps are quite slow on it, and I would imagine since the hot cam is also a GM cam, it probably doesn't have really aggressive ramps either. Another thing I don't particularly care for with the ZZ4 cam is how much difference there is between the intake and exhaust profiles (208 dur.,.474 lift on the intake, 221 dur., .510 lift on the exhaust). Seems like too much bias on the exhaust side to me. The faster ramps is why Comp calls them the "Xtreme Energy" series. In theory, it seems to make sense to me, so I figured why not? I'll have to post up after I get the new motor in, and let you guys know if it works well or not. Driving down there tomorrow to pick the cam up from the guy. I'm starting to get excited now, cause once I get the cam, I can finish putting the motor together, and get that bad boy dropped in the car finally!

 

Run the new OBDII system and you'll never have to worry about cam vs computer again. I'd look into one of the XFI cams.

 

yea for my future 383 im goin with XFI cams.

 

Thats just how weak the exhaust is on them ZZ4 ( 113 ) vette heads . It needs that mutch duration ( guessing ??? ) . But the first proposal you said with the ported TPI , ZZ4 camshaft , stock 083 heads. I got 251 rwhp and 318 rwtq on a stock APYP corvette .bin file . It actually idled better on my stock 305 tune . I have the graph on my cardomain site . I believe the dyno was a bit low too as others said their numbers were low comparred to other dyno's.

Best of luck man !

 

i have been following that thread since the beginning, Once i have my motor back together i might start gathering the parts to do the conversion, but only if i can find somebody in my area that can tune that system.

 

Which OBDII system are you guys referring to? The stock GM system like the 4th gens have, or an aftermarket DFI system? Never mind. Just did a post search and found what you're talking about. That post is so huge I haven't set aside a couple of hours to actually read through it yet! Lol. Mike (S10 Wildside) builds some killer electronic stuff though, so I'll bet it'll be a great setup if and when he gets all the bugs worked out.