Ls7 454 [Archive] - Chevelle Tech

: Ls7 454


deadpool1988
Oct 23rd, 09, 5:22 PM
does anybody know the cam specs for a LS7 454 or know where i can find them?

LS7
Oct 23rd, 09, 5:28 PM
http://www.gmpartsdirect.com/performance_parts/store/catalog/Product.jhtmlPRODID=2614&CATID=485.html

deadpool1988
Oct 23rd, 09, 5:32 PM
thanks for the information i needed

LS7
Oct 23rd, 09, 6:00 PM
You're welcome. :thumbsup: And welcome to Team Chevelle Jeff. :waving:

MEJ1990TM
Oct 23rd, 09, 7:20 PM
For some reason I was thinking they came with the same cam as the LS6's. Guess I was wrong.

kettbo
Oct 23rd, 09, 9:11 PM
3959180 - Mechanical Flat Tappet

This mechanical flat tappet is a ZL-1 and LS-7 mechanical lifter competition cam, good in 427-454. (Use spring P/N 3916164.) The duration at lash point in degrees (intake/exhaust) is 327/333; duration at .050" tappet lift (intake/exhaust) is 262/273; and maximum lift with 1.7:1 rocker ratio (intake/exhaust) is 580/620. Valve lash is .024/.026 and lobe centerline is 110 degrees.
Technical Notes: Distributor P/N 1104067 or melonized distribuor gear P/N 1045613 must be used on all crate engines with steel camshafts.

Hmmmm, remembering the specs as somewhat different that this .580/.600 lift.....
I helped a pal put the crate engine PN 774 in his 70 SS Chevelle. OMG, what a BEAST!

Adrian D.
Oct 26th, 09, 1:25 PM
http://i136.photobucket.com/albums/q182/royalbrett/LS-7Specifications.jpg

kettbo
Oct 26th, 09, 3:03 PM
OK, .560/.580" does sound better to my memory than when I wrote .580/.600" the other day

Not sure what cam "LS7" and his sources are looking at in Post #2? Engineering does change specs from time to time....:confused:

justkyle
Oct 26th, 09, 3:07 PM
I wonder how well that cam would work in a 496?

LS7
Oct 26th, 09, 5:14 PM
http://i136.photobucket.com/albums/q182/royalbrett/LS-7Specifications.jpg

OK, .560/.580" does sound better to my memory than when I wrote .580/.600" the other day

Not sure what cam "LS7" and his sources are looking at in Post #2? Engineering does change specs from time to time....:confused:
:noway: George, the numbers in my link are correct. :yes:

You will notice that there are two different lift specifications in those two articles that Adrian posted. :D

The first article (lower left) has the correct numbers minus the specified lash. ;)

LS7
Oct 26th, 09, 5:30 PM
Maybe the .560 and .600 numbers you keep refering to are measurements taken @ .015". :confused:

http://www.geocities.com/MotorCity/Downs/3000/cmspec.html

2. Any value in parenthesis ( ) is calculated. All lobe centers and distance between lobe centers are calculated. These are not advertised values. As such, they may be inaccurate due to lobe ramps ground non-symetrically.
If mechanical, deduct lash from lift to get actual lift at Valve unless marked as @ .015".

http://books.google.ca/books?id=seOU7F47NNwC&pg=PA56&lpg=PA56&dq=ZL+1+camshaft&source=bl&ots=aIrUTDbwcf&sig=HlQcVYhCvFKWmhSiwTRh62T4ZSo&hl=en&ei=Rw_mSt35BZCCNqC_uZ8D&sa=X&oi=book_result&ct=result&resnum=6&ved=0CBQQ6AEwBTge#v=onepage&q=ZL%201%20camshaft&f=false

In the above link you will also notice on page 55 that the '143' LS6/78/72 cam is listed as .500 lift when it is commonly known to many as a .520 lift. :thumbsup:

It all depends on where it is being measured. :thumbsup:

LS7
Oct 26th, 09, 5:43 PM
3959180 - Mechanical Flat Tappet





This mechanical flat tappet is a ZL-1 and LS-7 mechanical lifter competition cam, good in 427-454. (Use spring P/N 3916164.) The duration at lash point in degrees (intake/exhaust) is 327/333; duration at .050" tappet lift (intake/exhaust) is 262/273; and maximum lift with 1.7:1 rocker ratio (intake/exhaust) is 580/620. Valve lash is .024/.026 and lobe centerline is 110 degrees.
Technical Notes: Distributor P/N 1104067 or melonized distribuor gear P/N 1045613 must be used on all crate engines with steel camshafts.




Copyright 2000 General Motors Corporation.





:)

MEJ1990TM
Oct 26th, 09, 10:48 PM
What kind of street manners would a factory cammed 12:1 LS7 have?

westexun
Oct 26th, 09, 11:21 PM
I would never use that old technology. I built a flat tappet 468 with oval port heads on it that made 670 h.p. right after an LS-6 made 452 h.p. on the same dyno. The torque on my motor was 632 and the torque on the LS-6 was 520. I think camshaft technology has came a long ways since the seventys, even with the flat tappet stuff. Granted mine had a little more compression and good port work in the heads but I bet I had less money in my motor than the guy had in the LS-6, he payed someone to go thru his. I've been in a car in the past that had and LS-7 in it with a roller cam and I can tell you that thing was a pussy cat compared this thing.

MEJ1990TM
Oct 26th, 09, 11:24 PM
Was it a true to form LS7 that was 12:1, rectangular port open chamber heads, with the bigger solid flat tappet?

westexun
Oct 26th, 09, 11:58 PM
The ls-6 was all gm parts except for the reproduction tight lash solid from Comp cams. The ls-7 was bought new at the parts counter and had a comp 288 street roller in it. A buddy bought it from the guy who put the motor in the car, think he even built most of the car, a nice 55 chevy. You can't compare my motor to something that came offf of an assembly line. Waaay more tlc involved in the build.

MEJ1990TM
Oct 27th, 09, 12:27 AM
It is hard to argue with dyno numbers. I have no doubt your 468 is a very strong runner, but I think calling an LS7 a pussy cat is a little strange. Unless that roller cam just didn't jive with everything else that was there.

deadpool1988
Oct 27th, 09, 1:00 AM
you also got to put in a count that the LS6 was also said to be dynoed at a near 550hp in the 1970s.

kettbo
Oct 27th, 09, 2:45 AM
I got rides in many factory cars and upgraded factory units back in the day.
Not builds like now with oval port heads and trick roller cam stuff. I'll tell you, bar none, that the LS-7 was The King for over the counter fun back then. Like taking thermo-nuclear weapons to a knife fight.

westexun
Oct 27th, 09, 9:10 AM
My motor has a flat tappet cam in it not that much different than the ls-7 grind just more modern. It's even more of a nitrous cam and still makes decent power on motor.

LS7
Oct 27th, 09, 10:37 AM
Lets keep in mind, the LS7 was built and sold as a 3/4 engine assembly by GM for sale in mass quantity to the public. ;)

westexun
Oct 27th, 09, 10:51 AM
That's exactly what I'm saying about those production hippo engines. They go down the same lines all the rest of the stuff does. I bought a bowtie block years ago. The thing had to be line bored and the decks were nowhere near square. That thing was over 1100 bucks twenty years ago. The block in my motor has converted four bolt caps, line honed and square decks. It idles cold with about 75 lbs. of oil pressure. That 509 was built with all factory new parts and had about 30 lbs. of hot idle oil pressure, a little scary but it never came apart. This motor is way stronger than the 509 was, that had the huge iron square ports on it, even a blower. There's no substitute for a well thought out combination of parts and attention to small details when it comes to this stuff. A good head porter doesn't hurt either.

Adrian D.
Oct 27th, 09, 12:54 PM
What kind of street manners would a factory cammed 12:1 LS7 have?
I currently am running this engine, and have only driven it on the street with hopes of taking it to the track next year.
It is not the most friendly street engine, but it is manageable. The power brakes are not very good with that cam, but I mostly baby it around.
I need to change out the points and go HEI or digital, I haven't decided. I think this would help with starting, which I sometimes have a problem with.

R66SS427
Oct 28th, 09, 5:39 AM
So the LS-7 never came in a car from GM, but was an over the counter performance engine? Did I read somewhere that its a 512 casting # on the block?

LS7
Oct 28th, 09, 9:06 AM
So the LS-7 never came in a car from GM, but was an over the counter performance engine?
Correct. :thumbsup:
Did I read somewhere that its a 512 casting # on the block?
Not sure they ever used a 512 block for the OTC LS7 crate motor, the following casting numbers are confirmed (XCH suffix). :thumbsup:

289 '71-'79
959 '73-'90
445 '78-'90

Production dates taken from Mortec.

MEJ1990TM
Oct 28th, 09, 6:35 PM
I currently am running this engine, and have only driven it on the street with hopes of taking it to the track next year.
It is not the most friendly street engine, but it is manageable. The power brakes are not very good with that cam, but I mostly baby it around.
I need to change out the points and go HEI or digital, I haven't decided. I think this would help with starting, which I sometimes have a problem with.

Thanks. I dont' know if the engine I've got is an LS6 or an LS7. It's a four bolt main block but the engine suffix has been ground off. With the stock type LS7 cam what RPM do you have to be turning for it to be running efficiently?

I was told that the L78/LS6 solid lifter cam would be too small to run in something that was a true 12:1 engine. I'm still not sure what cam I'd like to eventually run in that engine, but the LS7 cam seems to be a good starting point.

So the LS-7 never came in a car from GM, but was an over the counter performance engine? Did I read somewhere that its a 512 casting # on the block?

Larry, I'm not sure who would have told you your Chevelle isn't a true muscle car. But they are an idiot. :thumbsup:

kettbo
Oct 28th, 09, 8:02 PM
My experience with the LS7 was it came into its power band north of 3500 rpm and was not laying down at 7000 or even 7200 rpm.....
The old song with the passage "...the lines on the road looked like dots..." is so true

sleeper
Oct 28th, 09, 8:03 PM
3959180 - Mechanical Flat Tappet

This mechanical flat tappet is a ZL-1 and LS-7 mechanical lifter competition cam, good in 427-454. (Use spring P/N 3916164.) The duration at lash point in degrees (intake/exhaust) is 327/333; duration at .050" tappet lift (intake/exhaust) is 262/273; and maximum lift with 1.7:1 rocker ratio (intake/exhaust) is 580/620. Valve lash is .024/.026 and lobe centerline is 110 degrees.
Technical Notes: Distributor P/N 1104067 or melonized distribuor gear P/N 1045613 must be used on all crate engines with steel camshafts.

Hmmmm, remembering the specs as somewhat different that this .580/.600 lift.....
I helped a pal put the crate engine PN 774 in his 70 SS Chevelle. OMG, what a BEAST!

The .580/.620 is correct for the lift without lash. In the ad that gave the specs the lifts are with lash subtracted. Add the lash to these and you are back at .580/620. I had a friend bought two of these new in 1989. One went in a 78 Malibu with full interior, 4.56 gear, 30-10.5 slicks, glide with 4500 stall. The car weighed 3410 with driver and ran 11.20's in the summer heat exactly like it came from GM, stock steel rockers and all. We put a Holley single plane intake, roller rockers, new 2 inch super comp Hooker headers, and it went 10.95-11.05. This was with a 750 dp Holley on 100LL fuel. The cam works very good. It makes good power, has gentle enough ramps for long life, and does not require exotic spring pressure. I would not hesitate to use it today.

MEJ1990TM
Oct 31st, 09, 9:44 PM
For a true 12.25:1 454 with 990 heads which cam would give more top end performance, the LS7 cam, or the L88 cam?

Here is the information I was given on the L88 cam.

Dual pattern, blueprinted replacement for factory (P/N 3925535) 435 H.P. 427 cubic inch early L-88 camshaft. Technical Notes: Basic RPM range is 4400-7000; compression ratio 11.5 to 12.0. The duration at .050 lift (intake/exhaust) is 264/269; valve lift is .560"/.580"; lobe centerline is 112.

I can see that the LS7 has more lift on both intake and exhaust, but 2* less duration on the intake lobe. The only thing I am not sure about is the lobe centerline. What does that mean?

From the talking I've done I've got it pretty much nailed down between one of these two cams, but I'm not sure which I would like to run when I get to putting that 454 together.

kettbo
Nov 1st, 09, 2:50 AM
Lobe centerline =lobe separation angle = point of max lift are spaced so many degrees apart. 106 or 108 LSA is considered tight. 112 or 114 is wide LSA

I ran the L-88 cam in my 68 Nova w/ 427 and 4.56 gears back as the 1970s ended. Very exciting indeed at 3500 rpm up to 6800 rpm. The extra cubes of a 454 would tame the wildness of the L-88 cam...something I have been meaning to try some time.

Love the sound of the L-88 and LS-7 cams.

MEJ1990TM
Nov 1st, 09, 3:06 AM
Thank you for explaining that to me George.

I kind of figured ,don't know if it's right or not, that for at least starters I am going to be running the 12:1 that it is at right now if the pistons are still good. I am thinking it only makes sense to have a cam to match it. If sometime later down the line I decide to tone it down for some reason it'd be fairly easy to swap out pistons, and maybe go to a smaller bump stick.

But for now I've got it in mind to go fast. :)

I've had quite a few people tell me that the combination of 3.73's and an M22 with the 2.20 first gear won't do me very well at the track. Since the LS5 car ran a 13.20 with an M22 and 3.31's I'll give it a shot. It actually ran that with an L78 but the only difference was the L78 is 11:1 and the LS5 is 10.25:1. Both engines had oval port heads with the same intake, carb, cam, and headers. Literally the same intake, carb, cam, and headers. When the LS5 got benched the stuff from the LS5 was put on the L78.

Thanks again for explaining that to me.

kettbo
Nov 1st, 09, 3:23 AM
you have an intake lobe centerline, and an exhaust lobe centerline. Add the numbers up, divide by 2 and you get your LSA.

My budget 454 in the Elky will be sold one of these days. See numbers below. In its place will be a 454 with all the forged goodies and 049 heads given the big valve treatment and a bowl blend. CR should come in at 9.5:1. I will be running a locally ground cam much like the 602A3 Lunati cam...on a 111 LSA. Much like the L-88 and ZL-1 cam lift wise....but the duration is lower....bringing the powerband in at a lower rpm...more street friendly. I should be running right at 12.0 in the quarter mile come April. I will be upgrading to 3.73 gears. Already upgraded to a 3000 stall converter...

A 454 with M-22 and 3.73 will be fine. Traction will be your enemy with a std trans.
I never could figure out that M-22 and 3.31 combo.....
Otoh, a great combo in my 68 RatVette s 3.36 and M-20 wide ratio gearbox.