Ferocity02

iTrader: (60)

Hello, I am now looking to get a cam for my 427 Ls1 engine. I am kinda lost on what specs to get for the things I want. I know it should be in the 240-250 duration range, if not more. What I am looking for from the build is a torque MONSTER! I am willing to give up peak power for torque. The car is 99.9% street driven, and runs up to redline don't occur often. I like the low RPM punches more, which is why I would like torque over top end power. I am would like the same driveablilty as my 224/224 114 has now, with a bit more lope, not like TRex lope, though. Passing emmisions is not a big concern, the cam will be changed around that time. The heads I will be using are GM LS7's with untouched intake ports and probably ported exhaust ports to help increase the low flow numbers. So a cam with a little extra exhaust duration would be nice? The intake valves will be stock GM LS7 titanium valves, and the exhaust valves will probably be regular stainless steel. The rockers will be the LS7 1.8 rockers. The springs will be nice and big to allow for the cam. I still haven't decided on the springs yet. That's pretty much it, if you need anymore setup info please let me know. Any suggestions are much appreciated. Thanks!

02WS6Bird

iTrader: (2)

big big cam...for torque monster

248/256 .5XX/.5XX 113 LSA
that oughta do it for your street driving


however if you really really will be gas conservative

stick with something like a Magic Stick 3 or G5X3 size or so MTI makes a crazy cam the G1 and have it in there 455 ci motor thats some food for thought

orangeapeel

iTrader: (18)

Those are small for his setup.

tbojbob

Got any idea what size combustion chamber you'll be using and the piston spec's....?

Ferocity02

iTrader: (60)

Chamber is 70cc's, pistons are 4.125" bore -10cc dish with valve reliefs with a quench of around .045". SCR of about 11:1.

DAPSUPRSLO

iTrader: (14)

Use a fast fast lobe on the intake for better ve without sacrificing torque via big .006" duration and that will help a ton. that titanium intake valve will let you get away with some fast valve action too. what rpm are you intending to buzz this thing to?

CamKing

Here's the cam I designed for the GMMG 427's.

300/304@.006"
245/247@.050"
.637"/.629" valve lift with 1.7 rockers
112-LSA

On the dyno they made 626HP and 590ftlbs of torgue.

Slowhawk

iTrader: (12)

I'm figuring if you are 11-1 with 91 octain Cali. gas you need some overlap to bleed off pressure so it doesn't detinate.No need for a huge Cam.

If It was my motor with a good intake and exhaust I would do
an XER- 236/242 .602/.610 on a 112 or even 110 duration.

The car would have to be tuned SD for the best drivability

We've made 500hp/485tq at the wheels on pump gas with 100% DD and a smaller Cam -408ci. The curve is plain awesome from 1500-6800rpm.Torque everywhere.

02WS6Bird

iTrader: (2)

only said those due to the previous testings in big cube motors

Haans249

iTrader: (24)

I think slowhawk is right about where you will want to be. Anything in the 240's for your 427 will be too large, esp with the 11:1 CR if you want Monster trq. I would do a 235/248 (LSK/XE-R lobes) which should throw your lift right at .684/.648 with 1.8 ratio rockers on a 111 LSA. I would also recommend running the PSI springs/retainers from Katech that are good to .700" lift.

235/248 .684/.648 111 LSA

Adrian

Ferocity02

iTrader: (60)

All great suggestions! A 235/248 seems kind of small to me, but it would probably allow me to pass emmisions here, maybe.

I was originally planning on using stainless valves, and then redline at 6600rpm, but now that I'm using titanium I think I might aim for around 7500rpm, reliably of course.

Haans249

iTrader: (24)

7500 rpms would be a tough buy esp with valvetrain stability. I don't think anything over 6800-7000rpms is necessary.
As far as the cam goes, its actually similar size to a 240 int dur with an XE-R or slower lobe, but will allow you to have higher DCR and more overall trq in your curve.
The key thing to remember with the LS7 stuff is the fact that the heads flow, and they flow really well. So to take full advantage of your setup, a lower duration cam is more then enough to feed the beast, yet retain your low end grunt.
If you think that a 235/248 is too small, then you could also shoot for a 238/250 using the renegade lobes, which will give you lift in the .65X/.66X range, but is not quite as harsh as the LSK lobe.
FYI, for my 446ci LS7 topend build, I went with a 242/256 (XE-R/Renegade) .646/.668 on a 113+2LSA.

JakeFusion

iTrader: (7)

Comp XE-R 244/248 .612"/.615" 112+1 LSA

Haans249

iTrader: (24)

You're going to need a lot more split in duration for that cam to work on the LS7 heads. The heads flow extremly well on the int side, but not so hot on the exh, probably why stock ls7 cam had close to 20 degrees dur split at 50thou. If you're going to run a 244 int duration (which will just be too much, because it'll leave you with a DCR of less then 7.5 with the XER lobes and his CR) you'll need atleast a 254-256 exh duration which doesn't exsist on the XER lobe either so then you'll have to start looking at other options, such as the LSK or renegade lobes.

Adrian

Full-Force

iTrader: (11)

I dont think torque is gonna be a problem in the first place with a 4" stroke. The 244/248 cams seem to be a popular choice for the 402/408 setups. I think that with a 427 that should be a fairly conservative cam.

Cam the hell out of it.

Slowhawk

iTrader: (12)

You need to update your post then.You were looking for good torque and a daily drivable car on 91 octain.Think about the rev range you will be in the most and go from there.Peak dyno's #'s are great for boasting but doesn't win races unless the car is setup to run a peaky setup
With a 427 street setup I would rather have a power range from 2k to 6400rpm.No need to rev out a stroker.

Ferocity02

iTrader: (60)

Right, my initial number is pretty high. I think 7000rpm would be just about right.

02WS6Bird

iTrader: (2)

on a 427 7K is really really high still for a streetable setup. Old BBC's peaked their numbers no higher than 6500 RPM's unless they were setup for the track adn the track only... Many peak hp numbers were in the high 5000's and peak tq in the mid-hi 3000's.

As said in the last post, smaller cams have done wonders in big cube cars, none of them are revving much higher than 6 grand. and these cams make excellent power under the curve as well as a table top torque number throughout the power band... these will also conserve gas.

seeing that you live in California, you must also keep in mind this stroker will need to pass emissions as you have said... You must be withing close range of the average 346 ci LS1 emissions yet with a BIG cube LS1. The smaller cam will be the only real way to do it and it won't be easy i am sure as you will likely need Long tubes and you will have probably removed smog emissions systems...so on and so forth. That is of course if Cali emissions testing is as strict as it seems to have been for the last who knows how many years...

http://motorsporttech.com/print/mti_...rochure01.html

https://ls1tech.com/forums/attachmen...achmentid=9480

DAPSUPRSLO

iTrader: (14)

This is not 1969. A stock ls7 motor goes to 7000 with a dead smooth idle and amazing torque everywhere from 2000rpm and up. With ls7 heads it isn't that hard to have a 427 very streetable that goes to 7000 or more. Now that being said with heads like the ls7 you don't need a ton of cam to rev to the moon either so take all this into consideration. Good luck.