lvrpool32

Looking at a roller cam (hydraulic) for my 396 small block.

Its all forged bottom end, 11.1 compression, aluminum heads, barry grant tri power...car is a 4 speed and its NOT a track car........mainly street with the occasional trip to Lime Rock or even the Glen.

I was looking at these two :-
Cam Style: Hydraulic roller tappet
Basic Operating RPM Range: 2,800-6,100 RPM
Intake Duration 050 inch Lift: 242
Exhaust Duration 050 inch Lift: 248
Duration at 050 inch Lift: 242 int./248 exh.
Advertised Intake Duration: 294
Advertised Exhaust Duration: 300
Advertised Duration: 294 int./300 exh.
Intake Valve Lift with Factory Rocker Arm Ratio: 0.540
Exhaust Valve Lift with Factory Rocker Arm Ratio: 0.562
Valve Lift with Factory Rocker Arm Ratio: 0.540 int./0.562 exh. lift
Lobe Separation (degrees): 110
Intake Valve Lash (in): 0.000
Exhaust Valve Lash (in): 0.000
Computer Controlled: No
Grind Number: CS XR294HR-10
Quantity: Sold individually.
Notes: Requires thrust button and wear plate.
Camshaft, Hydraulic Roller Tappet, Advertised Duration 294/300, Lift .540/.562

or :-
Cam Style: Hydraulic roller tappet
Basic Operating RPM Range: 2,500-6,000 RPM
Intake Duration 050 inch Lift: 236
Exhaust Duration 050 inch Lift: 242
Duration at 050 inch Lift: 236 int./242 exh.
Advertised Intake Duration: 288
Advertised Exhaust Duration: 294
Advertised Duration: 288 int./294 exh.
Intake Valve Lift with Factory Rocker Arm Ratio: 0.520
Exhaust Valve Lift with Factory Rocker Arm Ratio: 0.540
Valve Lift with Factory Rocker Arm Ratio: 0.520 int./0.540 exh. lift
Lobe Separation (degrees): 110
Intake Valve Lash (in): 0.000
Exhaust Valve Lash (in): 0.000
Computer Controlled: No
Grind Number: CS XR288HR-10
Quantity: Sold individually.
Notes: Requires thrust button and wear plate.

Camshaft, Hydraulic Roller Tappet, Advertised Duration 288/294, Lift .520/.540, Chevy Small Block, Each

Thoughts???

Nick

Gordonm

I like the bigger cam. I always here that with a lot of duration you lose bottom end. Yea a little but with gears in the rear I'm out of the low end almost instantly. I am running 248 @ .050 on mine and it runs great on the street and track. You have plenty of compression to run the first one. Either one I don't think you will be wrong but I like the first one.

gkull

I have cam #1 in my 427 sb only I'm running solid rollers on the HR cam. It's radical enough for me. I would not use it on less than 400 ci

Cam # 2 I use in my 7500 rpm 383 only I had it gound 4 degrees retarded and with 112 lc. Pretty radical for 383 as I installed it with 1.65 rockers and solid lifters. Your 396 and the 4 degrees of ground in advance with 110 lc will make it a good hot rod.

I'm glad that your building a 396ci

LFZ

what kind of heads are you running? I was looking very hard at the XR288 for my engine which is still being built...but opted against it. I do like the specs on that cam...should go well with your 396.

zwede

I would not get an off-the-shelf comp cams. I hear they are cast core these days and have a lot of failures. The custom ground CC can still be had on a steel core and are much better.

If you plan to drive it primarily on the street I'd stick with the smaller size. Maybe even consider a 112 LSA. I'd also recommend you fill out a cam spec request at cam motion. They're a smaller outfit and I hear good things about them.

lvrpool32

Anyone got opinions on the crower, crane or isky cams????


Nick

norvalwilhelm

What happens if you have an overdrive transmission. You are not over the sluggish bottom end. You are driving in it.
A car with 355 gearing and overdrive spends alot of time in the 2000 rpm range. If you downshift the rpm jumps to 3000 where the motor likes it but also gas mileage, noise, wear and heat go way up and if you drop into overdrive the motor falls on it's face.
The transmission and gearing greatly affect the cam choice.

Gordonm

I do have an OD trans. It is not very good at under 50 mph but I cruise the highway at 2200 to 2300 rpm which is around 70 mph. The engine seems very happy from 2200 to 2500 rpm. If you were running anything lower than 3.55 gears you need a cam with less duration for sure. This is why I kept the 3.70 gears

enkeivette

I have cam number two and I drive it on the street everyday. It's a very big cam for the street and cam starts to deliver power at about 3500rpms. Wouldn't want to move it much higher. But mines a small block 383 with 10.2:1. Having the bigger cam would let you take advantage of the higher compression and those extra 13 cubes.

Also if you're running 6 inch rods don't forget to get a custom grinds small base circle cam and a stroker clearanced oil pan. Also with those hydraulic roller lifters you'll need to get stiffer valve springs if you want to spin past 6K.

GOSFAST

You don't give one of the most important numbers up there, which is the runner size in the heads (or brand) or the CFM passing through them. If the runners are over 200 cc's, you are going to give up a little torque, they'd be best between 185 and 200. The second cam is the one we use in ALL base 383"/400" units with the retro Hyd. Roller setup for street use (mainly), and given the fact you only have an effective C.R. of 10:1 with the alloys on top, it would seem the choice. We have all units around 490 HP @ 6100 RPM. Judging by what we see on the dyno, I would figure the second cam is going to want to run slightly higher. Just make certain of one item, that you have enough spring pressure to keep everything stable. We're "battling" the BB's at 6550 RPM now with the same setup (Hyd.Roller). Don't listen to the manufacturers for spring pressure, talk to "builders". We run 150#/160# on the seat and 360#/370# open (depending on cam lift). Thanks, Gary in N.Y.
P.S. These units run fine on 89 with 10.5:1, they race on 93. We do have an 11:1 468" SB, 732 HP (N/A) running on 89 up here on Long Island and racing on 93 also. Your unit should be OK on 89 for everyday use.

lvrpool32

Stroke - 3.875 Int *Int Balance
CID 396
Rod - 6" Bushed (H beam)
Rod - 585 Grams
Piston Wt Grams / Type = 387 Hyper
Piston Type/ Dome Ft+6cc
Vol compression 11.2 to 1

head are 68cc, runners are 187cc I belive (there holley heads)

My goal is for torque, torque and more torque.............not ineterested in running the salt flats.

Wasnt too sure of wethe I needed the small base circle cam or not. But I have been told with the stroke and the 6" rod i will need one. Wheres a good place to get the small base circle cams??

Nick

gkull

You need to rethink your compression if your installing +6 pistons

lvrpool32

sent you a PM

Nick

gkull

Yes you will need small base circle. So no your not going to get them from Comp Cams. With high compression. That is anything over 10.7 you have to look into the "Dynamic Compression ratio" So it's a figure derrived from the static C/R and your cams overlap numbers. This number should not exceed the 8.4 range unless you want to run race gas.

GOSFAST

If you use KB pistons, which we don't, you'll find they measure their "domes", "dishes", and "valve notches" in reverse of everyone else. They consider domes as negative and vice-versa. I assume what he means in the post is actually a 6 cc notch. We've called them at "Silvo-lite" numerous times to change it, but to no avail. Thanks, Gary in N.Y.

gkull

-6cc piston will get you 11.2 static compression ratio. Now you need to get a dynamic compression ratio with your intended cams.

My original 383 with 11.2 static and the Crane Cams solid roller 232/240 with 112 lc had so little overlap that it was very octane sensitive. It was right on the edge of our local 91-92. I was running max advance of 32 mech. just like Dart said for their fast burn heads. When I went up in duration to 240/248 with more overlap the dynamic compression went down enough that it never pinged again.

Crane cams are sold as small base circle. Comp Cams could not sell me billet steel roller cams in a small base circle (.930) or less

enkeivette

I'll agree with that, the heads are really the determining factor. I'd call the head company and see what cam they would recommend. Before I bought mine I had a consensus between AFR and Comp that Cam#2 was the cam for me.

And what do you mean alloy heads effectively lower compression? What kind of alloy? For the moment I'll assume that you're talking about aluminum in which case I don't agree. I've heard that aluminum heads can effectively lower CPR at most half a point with advantages that far outweigh this, but a full point?! Sounds like someone has aluminum head envy.

enkeivette

Also another thought, I used Dyno2000 software and put in all my specs with the variable of a 1.5 or a 1.6 rocker arm. And with the larger corrected cam specs I actually made less power. Check out these pics. They're not perfect but they are a good indication, strictly mathematical no bias. You should be able to download this program for free off of LimeWire.



(1.6 rocker corrected cam specs)

MotorHead

Just a little info, I run a 242/248 duration cam with over .600" lift in my 406ci and run it at 1500 RPM on the highway in OD ( about 65 MPH ) and it has lots of power there, feels very comfortable with no strain on the motor at all and I can put my foot into it and it takes off. This is with a 3.08 rear end and 215cc intake runner heads, single plane intake, 825CFM carb yada yada yada

My vote is for the bigger cam ( and bigger heads )

enkeivette

Damn, nice setup. How much hp/ tq? I'd guess close to 600.