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So my 84 vette is mostly stock besides ported heads. And I've been looking around for a good flat tappet cam. I know theirs a ton of threads about this but alot of them are just people arguing what cam is better. I've been looking at comp cams, isky, and some others and have seen decent cams but I just want a little input from other people before I finalize my choice. My goal is to port out my intake manifold and have a cam that chops pretty good/loudly but still idles somewhat decent and still be streetable. And also make a decent jump in power for a L83 engine. Preferably one that would work with the stock computer(although I'm not completely opposed to getting a tune). Any suggestions appreciated!!
Edit: Also thinking about changing gear ratio so keep that in mind aswell
Last edited by My84isMeanToMe; 06-07-2023 at 07:27 PM.
Reason: I forgot to say something
Chopping, idling well, and working with the stock ecm aren't all going to happen... what do you actually want from the changes to the car. Auto or manual. There are a lot of missing pieces here. You are also looking at swapping springs if the stock heads are in play and you have to worry about valve lift etc.
Chopping, idling well, and working with the stock ecm aren't all going to happen... what do you actually want from the changes to the car. Auto or manual. There are a lot of missing pieces here. You are also looking at swapping springs if the stock heads are in play and you have to worry about valve lift etc.
Yes I plan on getting new springs, I'm looking for some low-mid range power and I have a manual car. Honestly idle isn't super important to me as long as it doesn't die out everytime i go to a stop sign
I put a Lunati Voodoo cam In my 86. You can hear it at idle, not extremely choppy but doesn’t sound stock at all. Also, make sure you install new lifters with whatever cam you choose because the used ones will not be good
I put a Lunati Voodoo cam In my 86. You can hear it at idle, not extremely choppy but doesn’t sound stock at all. Also, make sure you install new lifters with whatever cam you choose because the used ones will not be good
What are the specs for it? And how would you rate, just in terms of drivablity and how the car drives now compared to what it was like?
Off the top of my head I believe it is 227/233 .498/.498. 112LSA. Hard to tell what the cam has done to the motor because I did a ton of other work to it all at the same time. It is definitely noticeable though
Like Paul mentioned above, a stock ECM does NOT like a lot of overlap and the ECM will wig out. In other words, you can not stray too far from the stock duration or the ECM will not like it. If you want to go fairly big on the cam, replace heads etc... Go with the EBL and start tuning. Ask 84 4+3 about his 84 and the EBL. GL
Off the top of my head I believe it is 227/233 .498/.498. 112LSA. Hard to tell what the cam has done to the motor because I did a ton of other work to it all at the same time. It is definitely noticeable though
You have Mass Air. OP has Speed Density. OP's car won't take a 227/233 cam and run worth a darn.
OP, I'd look elsewhere for power unless you want to get into tuning. I put a mild 212ish Comp cam in my CFI and w/no tune, I couldn't tell a difference. It was a waste of time....then it ate some lobes.
Cam lift is dependent on how well the heads/ports flow at various lifts. If the max flow is at .400 lift, and perhaps a few cfm higher at .500 lift, putting in a cam with more lift than perhaps .450 will result in a doggy-feeling, lower-performing engine. There are a couple of threads on here about "Flow Benches" and port flow. There may be some clues to what the flow of your heads is.
Duration is a function of RPM range. L83 with puny heads don't rev very high. Again putting in a lot of duration will result in a poor performance and drivability. You want a dual-pattern cam for puny heads.
ECM control can be improved or 'saved' by pushing the LSA wider.
I use Isky cams because they are 10 minutes from my house, I know the guys there; they know me, I get a discount. So I have their catalog. I would pick 201262/270-12. 208/216 duration @ .050, .435/.445 lift, 112 LSA, RPM range 2000-5700. Their description: Excellent performance cam with good vacuum, good idle. 3.08-3.73 axle ratio, 9.5:1 compression ratio. Up to 650 CFM carb. Computer compatible. Stock converter. You won't get your "sounds like a big cam" idle, but you'll enjoy driving your car much more than you will if it has "too much" cam.
I'm sure lots of cam grinders offer similar profiles to the Isky I outlined above. The Isky above also looks comparable to TomCFI's Comp Cams "212". He couldn't tell a difference. You probably won't either. Your limitation to power are the puny heads and flow rates. There's not much improvement possible. It doesn't matter how far or how long the cam opens the valves if the ports don't flow.
What heads would you recommend then? I don't have a massive budget for this so that's why I just wanted a cam in the first place. I know my heads are ported but not anything good by today's standards.
If you are hell bent on replacing the cam, think heavily on going to a retro roller kit cam regardless of brand you select. Nothing worse than replacing a cam with a FT and having a lobe(s) go south at break-in or shortly after that. This is just my opinion, but it will be money well spent. I'm sure others may have a different opinion on this as well. GL on your decision and cam selection.
Because I'm cheap....and for practical reasons, I would start with a ported intake, headers and dual exhaust, and "free mods". Well done, that should get you to ~260hp. That's pretty wicked, for not a lot of money. Car will be pretty fast (mid-high 13's), punchy and wicket throttle responsive. FUN.
To exploit a cam, you need heads. I would try to find some used 113 heads (later L98 aluminum heads) for dirt, and buy those and give 'em a light porting. I'd port the living bejeezus out of the intake and do the radiused inlets like mike111 has shown to work, then I'd put in a mild cam, still. I don't think that "cam" is where to "find power" with CFI. Intake, exhaust, then heads are the low hanging fruit and a bunch of cam makes it run shitty, lack low end torque, and harder to tune.
Anyway, mild 113 heads, a mild cam and good exhaust, that ought to put you right on past 300 CHP net, and if I wanted more than that, I'd rethink my whole strategy and combo, from displacement on up.
I read a lot about flat tappet problems. here's a list of what I can remember off the top of my head.
here are the claims.
have to use high zinc oil, not adding a zinc additive to oil, because additives need to be added to oil in a special way so oil will form a protective film.
poor quality control. Improper crown and wrong size chamfer of lifter edge. Bad taper on cam lobe.
need to use original GM style with harden pad. can benefit from having an oiling slot.
2 cam core manufacture in Michigan, for USA made cams. both good. one guy tested a bunch of cams for hardness
So the quality is controlled by cam grinder. the taper on the lobe has to be right and the crown on the lifter has to match. so the lifter will spin.
break in with soft spring. add extra quart of oil for break in. so more oil splashes on the cam.
I don't know how to tell if the cam companies did their job right. so I went to roller cam. Howards does sell Max certified cam and lifter kits for flat tappet
I ordered a Howards CL110235-12 . 266/270 213/217 .485/.495 lift with 1.5 rocker, 112 lobe separation. good idle and vacuum. might have to buy new computer and tune it. couldn't locate the comp cam I was looking at. one place said they quit making them. I don't believe that. they probably quit stocking them and now its a custom order. oh well, don't have to machine heads for springs now. I think this manifold could benefit from a little more duration. the exhaust flow plenty.
Ported intake manifold flows an average of 215 cfm with clay entrance, all ports are within 3 cfm of each other. 213 cfm with dart head. 203 cfm with dart heads and stock bore TB's . I'm guessing the stock bore TB's are the choke, at this point. going to test that.
dart heads, ported manifold, stock top with swirl plates and stock TB's 198 cfm.
stock intake manifold flow 148-158 cfm, at least the ones I have.
I think you will find that the TBs are the restriction. I run 2.13" TBs, 54.10mm or 108.2mm total and I found that on a dyno I still have vacuum or a restriction at WOT. It's not much, but it is a restriction and the TBs are the issue, not the manifold or the heads. I plan on mounting another set that I'm doing of 2.21" TBs, 56.13mm or 112.26mm total on my motor and then go back to the dyno and see if the restriction is gone. A restriction is hp loss. I also plan on doing a couple other things to increase my motors hp, and no, it's not with boost. Again, for me, my goal is to run at least 11.99 NA.
be aware when porting intake, that the water jacket goes up into the runner dividers in 2 places. entrance of 7 and 6. entrance 2 and 3 ,about where the balance holes are on later intakes and same place on the early model intakes that don't have balance holes. wall thickness varies. taper on the width isn't much, from 1.125 to 1.2. thats only .0375 per side. If I had a sonic test, maybe it could be bigger.
this is what the port entrance looked like without round rod welded on top. flows 190cfm. Its hard to see, it is tapered. top is tapered more then the sides.
this shows the water jacket pockets that go up into the dividers.
really like the roller suggestion, if you're gonna replace the lifters anyway. my last '65 i went to the GM sbc crate roller motor, which made the stock 365hp L76 look sad. now i'm working on a 1982 that just feels SLOW compared to other older vettes i've had
sure been looking for your Buccaneer posts on what you did to your L83, could you point me in the right direction? you obviously have made a lot of comments over the years and i'm in need of some help in finding out how to make my '82 awesome. looking at all the first hand experience, i think i want to stick with the crossfire setup and maybe benefit from the poss return of the Renegade that was just announced. but yr 12 second version seems enticing!
any help would be most appreciated! i already have an appointment for a header/exhaust job, will probably see what happens there before i port the stock manifold and maybe replace the heads, possibly a new cam. the '82CE is such a step up from my previous C2/C3's in comfort and convenience, i hope to keep it a while (the wife even likes it!)
Hard to give advice w/o knowing your goals and budget. In post #1, the OP asked about a cam. That could be about a $150.00 project. Pretty low dollar there. OTOH, Bucc, has a 383 with heads, roller cam, Renegade, TB's, headers....and more. That's Thou$ands.
Where do YOU 'land', budget-wise? Since you're paying someone to do headers and exhaust (a great first mod, BTW), I'm guessing you got some dough....but throw out some budget and goals and you'll get better advice.
Keep the LSA at 110 to 112 on a stick shift car. Good springs and 1.5 Roller Rockers on any cam you chose. 84's need headers and free flow exhaust are a must. The 113 heads are excellent and made 250hp stock on 1991 vettes. Good Luck, some excellent advice offered in this thread... Cheers... _ Jarrod
dumb question: is there a way to keep the smog pump (AIR) when going to headers? finding headers that will accommodate AIR seems difficult!
jealous that you've gone to a 400 sbc, would love to do that but my 10,000 orig mile 350 would have to sit in the storage shed. meanwhile, gonna have to find another way to make the .82 a bit more driveable. with the exhaust sys as a starting point i'm not sure what will happen if i can't go to headers and a hi flo cat. maybe as an "historic vehicle" here in Merrieland i can quit worrying about the DMV ****'s, more thought required
dumb question: is there a way to keep the smog pump (AIR) when going to headers? finding headers that will accommodate AIR seems difficult!
jealous that you've gone to a 400 sbc, would love to do that but my 10,000 orig mile 350 would have to sit in the storage shed. meanwhile, gonna have to find another way to make the .82 a bit more driveable. with the exhaust sys as a starting point i'm not sure what will happen if i can't go to headers and a hi flo cat. maybe as an "historic vehicle" here in Merrieland i can quit worrying about the DMV ****'s, more thought required
06-07-2023, 07:20 PM
84 vette cam suggestions?
