not sure which cam to go with ?? i'm building an stroker lt4 383 with
3.75 crank and 5.7 rods .buying my srp pistons this week and need some
recommendations for an all-around good cam for street and strip w/ 1.6
roller rockers !!prefer hyd/roller cam,but might try the true roller/mech...
with some advice.......?????????thanx,guys
:chevy :confused:

 

I would think the hotcam would work best with that

 

i went with the LT4 HOT cam ... it's 218/228 .525/.525 LSA: 112. You've got the 1.6 roller rockers already with the LT4, but might want to upgrade to some pro magnums or something.

 

You've got lots of options, one of my biggest questions to you is...do you have to pass emmissions tests? If so the Hot Cam would be a decent choice, but I would recommend the Comp Cams 305 over the Hot Cam. If you don't have to pass emissions then the sky is the limit! Comp Cams 306 is a nice cam that's not TOO roudy and will put out some really impressive power! I'm building up my LT4 right now with a heads/cam package...I went with the Crane #109831, it's just a little bit bigger than the CC305. Here are some specs if your interested:

Hot Cam Duration: 218/228 Lift@1.6RR .525/.525 Lobe Sep 112*
CC305 Duration: 220/230 Lift@1.6RR .533/.533 Lobe Sep 114*
CC306 Duration: 230/244 Lift@1.6RR .533/.576 Lobe Sep 112*
Crane 109831 Duration: 222/230 Lift@1.6RR .542/.563 Lobe Sep 112*


[Modified by Zix, 7:27 PM 2/18/2002]

 

Remember that the bigger cubes will make the cam act much smaller, the hotcam is a great stock cubic inch cam but with the bigger cubes I would go with something bigger. I just picked up a Comp Extreme Energy Cam 224/230 duration, .536/.544 lift (1.6 rockers) 112 LSA this is a step up from the hotcam and it has a very fast ramp rate so it will produce more torque and throttle response. I guess it will all come down to if you need to pass emisions or not. Good Luck.

Mike

 

ZZ409 in my 396. 226/226 555lift with 1.6 rockers. 400LBS of torque at 3200RPM's with no major HP drop off till 6400RPM's. This cam is a great compromise between the CC305 and CC306.

 

I liked the price of the HOT cam ... under $200 is sweet ;) SOME day .. i may put in a 306 or bigger once I get another car. I wouldn't want to use a 306 cammed 383 as a daily driver with 11.55:1 compression! :eek: :eek: :eek:

 

advertised numbers aren't always a good comparison. actually measuring a cam tells much about ramp rates. those ramp rates, and duration at higher lifts, seem to mean more than "advertised" and .050" numbers.

a solid roller is a good example of this. a solid roller with 240 degrees of duration at .050" has less .050" duration than a hydraulic roller speced at 230 degrees (since the solid roller has .020" lash, the effective .050" duration is much smaller than the specified number). and yet, the solid still makes better power, and with much better driveability (now you know why).

if you want an engine that sounds stock (in terms of lope), the solid roller is a great way to still reach big power numbers.

also important is the cylinder head flow numbers at low lifts, like .150" and smaller. some heads are "too" efficient at low lifts, so race builders will sometimes use cams with smaller than normal overlap, or (more often) overport the heads to sacrifice low lifts on purpose.

there's the other extreme, too (like most unported, stock-type heads), where the low-lift flow is so small that you need massive overlap to make any power.

note that this is why race classes that mandate stock heads/intake use such huge cams, whereas all-out race engines can use something significantly smaller.

because of all this, custom cams seem to work better in almost every case. sometimes the difference might not be worth the cost, but it usually is (and more). of course, to get a custom close to ideal, you need good flow data for your cylinder heads, and this gets into another big problem...

 

Love my ZZ409.........Idle is a little rough but manageable. :blueangel:

 

This is an interesting point that I agree with too.

Have you ever seen a 'factor' or mathematical way to compare the two - hydraulic Vs mechanical?

I'm considering swapping to a mechanical roller and have been kicking around 224/230 Vs 230/236. I don't want to give up too much idle quality or low speed throttle response in the process just to gain power up top.

Jake

 

jake, i haven't ever used a solid roller that small. my guesstimate, based on how nice the manners are on much bigger solids, is that it will almost idle like stock. i certainly wouldn't worry about it, as it will have better manners than something like the HOT cam.

fwiw, too, solid rollers usually gain everywhere, even at the bottom.

i'm not aware of any formula, although i'm sure there is such a thing. there must be, since there are very accurate and complex dyno emulation packages available.

a friend of mine "rolled" many cams for me on a lobe measuring machine. i mostly looked at the numbers as area under the curve, but this ignored the actual events themselves (advance/retard, overlap, etc). most interesting is seeing how far from rated specs some cams are.