A friend of mine knows this guy who used to build drag engines. anyways he has this cam that he never used, i forgot the brand name and all of the other stats on it but he said that it had a .625 lift. he claimed it would be an extremely radical street cam, and that it would lope every other second or so. if thats true, would that wreak havoc in my computer controlled car? its a hydrolic cam (not sure if its roller) and he suggested that i install a torque converter with a stall of at least 2400. now the thing is hes giving me this cam for free, does anyone have any suggestions for me? should i consider installing it, having someone grind it? I really want a lopey cam, i love that idle where it sounds as if the car is gonna die if you need more info i will have the cam in my possession later this afternoon, thanks for any help

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1987 LG4 Camaro z28
Modifications- Flowmaster 80 series, KN airfilter, high flow cat, 180* stat, edelbrock performer intake manifold, msd blaster coil, ascd big block hood, panasonic cd player, rockford everything else.

 

That is way way way way way way way too much cam for an LG4.

 

can someone please explain to me the fundamentals of a cam? i still dont understand how a cam could be too much. does it have anythin to do with powerband/low end torque? thanks

 

Yeah, that is so much more than stock.. your heads wouldn't take it, and I doubt your car would idle if its as big as he says. Since your car is computer controlled, you want something much more mild. Look at the specs on your stock cam, and where your stock engine makes power. Higher lobes gives you more valve lift, more air flow. Higher duration has to do with where your car makes power, I'll bet you ten bucks that cam makes its power way too high for a street car.

Now, Im not really experienced with matching cams with carb cars at all, but I know you don't need .6xx lift on a 305. Something more like .45x would suffice. For the duration, check your stock cam--thats what your engine was designed for, and unless you're modifying the intake, I would only go a little higher.

 

It's entirely too much cam...

The valve springs will stack up to a solid cylinder of metal long before the valves are fully open. If you just stuck that thing in your motor as it sits, you would destroy all 16 push rods, all 16 rockers, and/or pull all 16 rocker studs. There are no valve springs with sufficient lift capabilities available in the correct diameter that will fit in the spring pockets in those heads, so you'd have to take the heads off and have them machined.

Opening the valve that far is pointless in those heads. The flow stops increasing when the valves get past about .475" open; so all that extra lift won't accomplish anything. The port is too small to allow any more flow.

A cam with that much lift will also have ALOT of duration. That is, it will open the valves much earlier than the stock cam will, and hold them open much longer. This is how you set a cam up for high RPMs. But, it causes a loss of low end torque and results in an extremely rough idle, and low idle vacuum. Your computer won't know what to do, and your carb won't feed enough fuel at idle since it's expecting 18" of vacuum or so and you'd have much less. Half as much vacuum = half as much fuel fed = extremely lean at idle and low speed cruise = very poor throttle response, bad gas mileage, dying at red lights, etc. etc. And of course, it wouldn't have a prayer of passing smog.

In a word, it's totally unsuited for an otherwise stock motor; or almost any street-driven car for that matter, no matter how aggressive the setup is.

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"So many Mustangs, so little time..."
ICON Motorsports

 

haha, i figured that cam was entirely way too radical, i just wanted to see some of the responses. lol, no chance at passing smog, my car can't pass to save its life . Anyways, thanks for the responses, and what should i do with this cam? Would i ever be able to have a street engine that would benefit from this cam? the whole reason i wanted this cam was because i wanted something that gave it the really lopey idle, i love how it sounds as if its gonna die as it idles. is there anything i can do to make it idle like that? any idle screws i can play with? thanks

 

I don't even think the car would hardly idle at all. I'm sure with this kind of cam the duration is extremely big, meaning the valves will be open for a much longer time than stock, and your super restrictive LG4 heads could not handle that. Waaaaaaaaay too much fuel to dump in there. Plus the fact that the vacuum would be so screwed over the computer wouldn't know what to do. No matter what you adjust on the motor, there's no way this could work.

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1984 Camaro Sport Coupe - Rebuilt 355 S/D TPI L98, Crane 2032 CompuCam, Crane adjustable fuel pressure regulator, MSD Blaster coil, custom burned PROM, stock TPI intake, Accel 24# injectors, gutted air box with K&N filters
F41 Suspension Package, 700R4 Tranny, TCI Breakaway torque converter, 3.27 Posi Rear
Hooker Shorty Headers, Catco High-Flow 3" Cat, Flowmaster 3" American Thunder Cat-Back

Best 1/4 Mile Run:
13.847 @ 95.91 MPH

1992 1LE B4C Police Camaro RS - 305 TPI 5-Speed

 

that's just a touch to big. almost .200 too big...............

 

one time, i was playing around with my engine (lg4) and foung a tube that looked like it went from the carb right back into the carb (turns out it went to the secondaries on the carb, just coudln't see it) anyways, i figured what the hell does the carb need suction for? so i blocked off both and went for a drive - couldnt tell much difference at all..... until the next mornign when the engine cooled down - took about 2 minutes to start with the pedal to the floor the whole time - eventually it cranked and man it sounded like one of those crazy cams with alot of lobe - unforunately i think i was running on 3 cylinders, and that's why it sounded like that.... oh yeah and there was a big ole cloud of smoke that poured out of the exhaust. lol how stupid i felt, thought my poor car was dying

 

thats exactly what im talking about. every morning i start my car and it does that, it acts like its got a huge cam in it, and it idles really rough till it dies. tons of smoke pours out of the exhaust and the carb. even when the car dies, it still smokes. what in the world is that? i know that its cuased by the code 15 ive been getting, its causing my choke operate incorrectly (over adjusted). i like how it sounds and idles, but i know something isnt working right. can anyone tell me what thats all about, why it'll idle like that till it dies? firing order, cts problem, choke problem? anyone? thanks

 

That smoke coming out of your exhaust is unburnt fuel vapor. I've had that problem with my firebird. I had to make sure to push the car out of the garage (if i was working on it the night before) before starting it up or i'd smoke out my garage. A code 15 means there could be something messed up with the coolant sensor, which would affect the choke and, i believe, keep the car in open loop. I remember i was working on my car one evening and i forgot to reconnect the coolant sensor and of my car smoked bad on start-up and was drinking gas even worse than normal, which is pretty bad.

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Red '87Formula Firebird
-mostly stock 5.0L LG4 w/cowl induction setup borrowed from '83 TA and T5 tranny.

My newest Ride:

'85 Silver L98 Corvette w/4+3 manual tranny. not bad for $3500.

 

dude that is bothering me soo much! the unburnt fuel vapor thats billowing out of my exhaust on startup. its not good to run on open loop at all times either, terrible gas mileage.... oh yeah, i finally got the stats on the cam now that ive got it in my possesion. well its an isky racing camshaft, and the cam lift is .440, the valve lift is .660, the valve lash is .028 (all intake timings) the exhuast timings are as stated, .393 cam lift, .591 valve lift and .028 valve lash. im sure its too big, but exactly how much bigger is it than i need? thanks

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1987 LG4 Camaro z28
Modifications- Flowmaster 80 series, KN airfilter, high flow cat, 180* stat, edelbrock performer intake manifold, msd blaster coil, ascd big block hood, panasonic cd player, rockford everything else.