Billy177

Anyone out there install a custom cam that had added duration and a different lsa, but retained lift that the stock valvetrain can handle, and had good results.

I know that this is not the best approach to make max power, especially since the lt1 heads dont low very well however for someone only wanting to spend a few hundred dollars on a cam it seems like a viable option. The car allready has full bolt ons

1994Z28Lt1

iTrader: (1)

dude your going about this all wrong update your valvetrain first with 1.6 ratio rockers and springs that can handle the biggest cam you would want to put in there, in the mean time it will give you a few ponies on top. then when you can afford to do it right your valvetrain is already up to snuff

why pay tons of money for a custom cam to gain little or no power

C_Rules

iTrader: (7)

it's hard to be patient but just keep saving up. do a heads an cam package. you'd have to run a small cam with the stock valvetrain and you'd probably want to go bigger later down the road anyway.

infinitebird

iTrader: (11)

There is no such cam.

The stock valvetrain (at least the springs) can not handle ANY aftermarket cam. Especially if it's a old worn out / high mileage valvetrain.

Don't do a cam without the supporting valvetrain. Best case, you don't make much power, worst case you get valvetrain parts embedded into your pistons.

LT1MAN

iTrader: (6)

yeah im pretty sure you still have to update the valvetrain even with a hotcam.

moehorsepower

iTrader: (3)

Your best bet would be the LT4 Hot Cam Kit, It comes with Springs, Retainers, Locks and 1.6 RR. and the cam specs out @ 218/228 with 525/525. It is a decent package for the price.....

Revelation Z28

iTrader: (10)

wait til 96capricemgr sees this topic, hes gonna go apeshit on the op

the stock springs on our engines are not the best as it is. they are already limited on the stock cam since people are getting valve float at 6000+rpm on the stock cam. get a set of comp 918s they arent much.

Billy177

First of all its not my car I was just asking if anyone had done it, secondly I find it hard to belive that changing the duration from 205/207 to something larger would not yield a power increase. I know thats it not the way most guys would go about it and I know its not the best way of doing it. I also know that there is no such cam out there now that is why I suggested a custom with a little added duration, more overlap however it would retain the same lift and base circle making the stock valvetrain compatable. I am gonna play with some numbers in desktop dyno and see what I come up with. BTW the car would still be shifted at 5800 if not lower.

sdm1234

iTrader: (8)

it's not worth the money/labor to put in basically just another stock cam with duration differences... especially with the LT1 heads choking everything, a simple cam like what you're refferring to won't yield too many results... you'd be better off just increasing the lift a little bit with a RR/spring/pushrod package for the same price. that way, you'll get the added insurance as well.

Billy177

ok according to desktop dyno mantaining the factory valve lift I was able to get 441hp out of it, made over 400lbs torque from 2500-5500. Ans was able to achieve 95% voluemetric efficenty at 5000rpm. It almost seems as if the reduced lift seems to promote better port velocity, giving the unexpected power increase that it does.

I however am NOT sure about the accuracy about the flow data and as far as the intake I figured setting it as a dual plane would be more accurate. If the flow data is correct I do not see how added lift could help since the heads dont flow any better with more lift, on the intake side and only marginally better on the exhaust side.

96capricemgr

iTrader: (1)

The stock springs are junk. If you could find a lazier lobe that has stock lift it might work but having to rev it higher for the longer duration will float the valves anyway aftermarket cams have much more aggressive ramps which will float the valve sooner even with the same lift.

Like someone said above do springs and rockers and keep the stock cam for now, that is a good upgrade, could even use the dirt cheap LT4 springs, they are perfect for 1.6 rockers on a stock cam but are not good for the HOT cam with LT1's heavy valves despite being sold as a kit.

I say this as a fan of smaller cams, I think most of the guys here go too big too soon.

A custom hydraulic roller cam is going to cost what $230+ and then you need gaskets and all even if you could keep stock springs(you can't), so for less money you can do roller rockers, ProForm work on mild applications, combine them with some LT4 springs and for less than the price of a cam you can have a nice gain.

I know someone will knock ProForm but I have about 47K miles on a set of 1.5s, most of that with a ZZ4 cam 208/221 .474/.510 with 110lbs on the seat springs. I handed the rockers to someone that told me ProForm was junk and he agreed the rockers are still in nice shape.

$170 or whatever it is for ProForms and $50 for LT4 springs.

ZONES89RS

iTrader: (25)

Well, if you are dead set you can run a Hot Cam with 1.5 rockers. That is your best bet.

Billy177

I would think the lobe would be fairly lazy being that the lobe lift is low, and I don't have a problem changing springs, I was basically thinking out loud about this, as an alternitive to new pushrods/rockers.etc probrally about a grand and this seems like it could be done for just under 500 out the door.

96capricemgr

iTrader: (1)

Heck then do a Crane 210/224 cam with proper springs and stock rockers and pushrods.

We were all ASSuming springs were one of the parts you wanted to keep stock and they are not negotiable, they have to be changed.

Far as lazy lobes, a low lift aftermarket cam will try and get the valve open FAST and keep it open a longer time to fill the cylinders and keep it open as long as possible then close fast, this is what would float the valves the rapid changes in lift, not just the max lift.\

Stock eliminators take this too a whole new level with stock lift but LONG durations and far as I know they actually design the lobes to throw and catch the lifter, they make BIG power on stock castings with stock lift but LONG duration. Not something you could use for the daily commute though.

infinitebird

iTrader: (11)

I have a hard time believing this from all the "should I go with the hotcam or upgrade to the 305" type threads I see in this section.

I have pretty much the opposite opinion, I think most people go with the older/smaller cams because they say they want something streetable, while not even realizing that the newer/more aggressive cams can be tuned to be just as drivable and will make more power as well.

96capricemgr

iTrader: (1)

How often do you see threads on the 847 and 306, I see a lot?
The latest XFI stuff seems to be crap, I am seeing lots of hype and no results.

The problem I see is guys can not sort out reality from reputation. There are a lot of HOT cam threads too but those are often the same guys who want stock stall or gears or some other glaring newbie mistake. I say that as having been one too, I did a mild cam with stock gears and 1650 stall MISTAKE.

IMO the 306/847 have no place in a stock cubes motor especially as a cam only with stock compression and I see a lot of guys wanting to do that.

infinitebird

iTrader: (11)

A LOT of people have run the 306 on stock cubes and done pretty well with it, that's why you keep seeing those threads come up. It's one of the most used and proven cams for lt1s.

I'm not really a fan of it either but not because I think it's too big for stock cubes. With supporting mods and good tuning it will run fine. On stock stall/gears most definitely too big, but really so is any cam. That stuff should be done before a cam for sure, and that's definitely where some people make mistakes.

Personally the cam that I've seen make the best power consistently on stock heads/cubes is the XE 230/236.

96capricemgr

iTrader: (1)

The locals I have known that went 306 and similar had M6 4.10 cars and ended up either selling the cars or they became garage queens because they no longer enjoyed driving them. They did not perform at the track either.

There is a difference between what people think performs and what really does.

There was a local 383 M6 car with a 306 and ported heads, at one point I thought 12.7 out of that car was impressive, today I see it as a perfect example of what not to do. In the 383 it drove fine and he enjoyed it. It was stock shortblock stock heads cars where guys got tired of it FAST.

nighthawk15

Well I'm just gonna let the others bite each others heads off and leave you with this: A cam swap is not an easy job, or a cheap one. If you are going to put yourself to the trouble in the first place make sure you get what you really want. If you don't you will regret it later.

69gto96z

iTrader: (13)

Buy the cam, I would say a cc503. Buy the crane 10308 spring kit, it is more than enough for the 503, and run stock lifters/pushrods/rockers. When you get the money, buy a set of studs, guideplates, and 1.6 NSA rockers. That will take 2 hours max to install, and will really wake the cam up a LOT. I went with a 306, and honestly, I wish I would have gone with the 503 or gone custom. I don't really enjoy my 306 that much. The car performs well, but cam surge is a PITA, and im to broke to get it dyno tuned. So my MadZ28 tune will have to work.