Matt Gruber

i was wondering if his cam might work well with the vortec heads?
Any info on street use appreciated. :cheers:
dyno tests would be great!

Fevre

Matt

Believe dman535 (derek) is running an LT1 cam but it might a 72.

Lt1er

Why would you want to? If your a purest, yes. If your into performance NO!

That grind along with everything in that era and before is old technology. That's why I chose Crane Power Max solids many years ago. I have more power with nicer idle, gas mileage, decent vacuum, 91 octane friendly.:)

Every once in awhile I come across a low mile or rebuilt LT1 like mine and it's day and night difference. By the way mine has much more lift and duration than stock :thumbs:

Matt Gruber

There are some guysin the c2 section that swear by it. i have an open mind, so if it is a good cam i'd like to know more about it.
Sure sounds obsolete, especially the .435 lift.
But it works with stock springs, and winds to 7000.

Barry's70LT1

I'm currently using that cam.
Over the years I have tried different cams (Crane) and I still like the LT-1 cam.

With that cam, (old technology as it is), street tires, I have managed to run 13.02 @ 110 in the 1/4. Stock (old technology) heads, intake etc.

I would like to try a dyno some day.

There is definitely nothing "wrong" with that cam.
But, as lt1er said, there are more modern grinds.

Not having tried these, they may be better.

Duke, and some of the other experts are very qualified to do this comparison.
This topic comes up often.
Have a look in the archives,

Barry

Rowdy Rat

With good reason...

If you are running a lot of compression, stock heads, and exhaust manifolds, it is an excellent camshaft... Even with thirty year old technology.

If your combination differs from the above statement, then all bets are off! :)

It is a very good camshaft when used in its original application (i.e. the 1970 version of the LT-1 engine). A little flat on the bottom end, but that's not a bad thing when trying to launch a car with street tires.

Actual lift figures (including the lash) are .458" on the intake and .485" on the exhaust... Duration I believe is 317° on the intake and 346° on the exhaust (duration on these camshafts were originally taken at .006" off the base circle, not .050" industry standard). If you ever saw the flow figures of the stock "186" head, you'd know why the engineers decided on the specs.

Actually, the stock springs were originally intended for press in rocker stud applications and the LT-1 could really use a little more spring pressure when the valve is seated... The engine internals will see the far side of 7000 rpm if properly prepared, but the camshaft falls off on power after 6000 rpm or so... No need to push it much harder than that.

It's old, but it still gets the job done.

Regards,

Lt1er

I'm running the power max 278 mech with 1.6 CC roller tips. My 186 casting double humps are ported and polished screw in studs and guide plates. Manley raceflow valves with multi angle valve job bigger springs with chromoly 10 degree retainers. My compression in @ 10.7 with forged flat tops. Hooker headers and 2 1/2 pipes through dynomax mufflers.

My lift is something like .520/.540 with 1.6 It's the modern ramp profile and 114 lobe centers that give it such a wide power band. It's still pulling hard at 6500. I have run it to 7000 in years past. No way would I ever detune my motor with my old setup.

It's been my life experience that people that swear by something have a closed mind :skep: I'm not saying mine is the best cam either. For solid mechanical street machine it rocks. Some day maybe next rebuild I step up to the roller cam and stroker crank shaft.

Robert N

It's been my life experience that people that swear by something have a closed mind

That may be true, but from the conversations I have had with some of the guys who like this cam, I would have to disagree. As Stan mentioned, for a stock setup, the original cam is hard to beat. You may have stock heads, but they are ported and polished and feature Manley raceflow valves with multi angle valve job bigger springs with chromoly 10 degree retainers. Add the headers and a difference in compression, and your engine is no longer stock. That also means, as Stan aptly put, "All bets are off". and your cam is a better fit for your application.

I have had/read this conversation before. The stock 70 LT-1 cam is a good cam for the configuration it was designed for. Modifying one part of the set up still will make that cam more than acceptable. Barry's is stock with the exception of the headers. The stock cam works well, as his track numbers prove.

I will probably run the stock heads and ram's horns, only with porting and better valves as I am interested in as close to a stock configuration as possible. I will probably stay with the domed pistons and 11:1 compression, so the origianal cam wins. I don't see that my intended set up will benefit enough from a modern cam. I won't know until the design is tested. If 'flow' increases enough, a modern cam might just be needed.


[Modified by Robert N, 9:42 AM 8/28/2003]

Matt Gruber

i'm thinking on a low budget engine.
vortecheads
LT-1 cam
RPM AIRgap
no need to upgrade springs on vortec heads.
compression over 10:1
1.6 rockers on intake 1.5 Ex
The goal is a fun to drive engine with decent mileage and long life.
But, if it didn't run the 1/4 faster than an XE262, or xe268 i would be hard pressed to recommend it. Except the EX cams really are not long life cams, and tend to suck gas at cruise.
So if the LT-1 got 18 mpg and ran 13.8
and the xe268 got 14mpg and ran 13.5 it would be a tough choice. i would go with the LT-1 in this example, since the goal is long life, and fun(6500-7000 is FUN)

Robert N

Matt, what are the specs on the Vortec heads? I seem to recall them being close to the stock LT-1 heads. If that's the case, the LT-1 cam does seem the better choice. May develop less power, but longevity and better mpg seem like a fair trade for .3 sec in the 1/4 for a fun toy.

I like the setup. Power, fun, longevity. Not the fastest, but a great all around engine with power to keep up with most.

Matt Gruber

Robert
from the Pace catalog:
Vortec:
64cc
1.94/1.50
LT1 high velocity port design
170cc intake
.
Vs,
12480092(LT-1)
64cc
2.02 1.60
Seats not heat treated
157cc intake
.
my example is not fact but the Question i am asking.
How do the 2 combos compare in the real world?
:cheers:

Lt1er

Matt - the 2.02/1.60 were 163-165 cc stock with the 64 cc chambers. The vortec have a higher cfm rating. So potential power is higher.

I don't know how much a stock mech cam and lifters is. Cranes cam and kit are fairly cheap.

Fevre

Little more info on the Vortec heads

http://sdpc2000.com/cart.asp?action=...art&catid=2172

Robert N

I show 161 for the cfm flow on a stock 70 LT-1 head.

Simply based on the specs, I am not sure with an otherwise identical setup, the difference would be very noticeable. I would expect the higher flow, even with the small valve diameter, that the vortec heads would create more potential HP at the higher RPM range.

The Vortecs are essentially a modern design of the LT-1 head. Assuming no other changes, the LT-1 cam should work well with them.

With Fevre's post on the .450 lift range on a stock Vortec head, the LT-1 cam seems a great fit based on Stan's post of "actual lift figures (including the lash) are .458" on the intake "


[Modified by Robert N, 12:25 PM 8/28/2003]

Matt Gruber

GM no longer makes it.
GM charges a license fee for the use of the LT-1 name.
it is not the same grind.
uses a 125# seat spring
won't work :cry

Robert N

Go figure. So much for my trying to build my engine to spec.

Matt, as you hunt don a cam, let me know what you end up with.

Robert

Chuck Harmon

Matt,

I used the 1st design racing #...140 cam solid cam with 2.02 slant plug heads and loved it. The engine was otherwise pure LT1. My engine guy talked me into changeing to a 292 Hydraulic cam with .502" lift. I was very disapointed with the change. I agree that modern grinds can and should be better, but millions of dollars were spent by GM in engineering their cams in the first place. They did a pretty darn good job making power with cams that would go 100,000 plus miles!

When I consider my factory spec L88 and the numbers it makes with technology almost 40 years old I am again impressed, as were the dyno operators who ran the test. There are very few un-blown/un-juiced combinations of any size on this forum or the ZO6 forums making more power than my L88. These new combinations are smoother and more civilized down low, which is why I am changing mine to a Crane solid roller, but I still must take my hat off to the guys that designed the factory cams in the first place.

Chuck


[Modified by Chuck Harmon, 4:24 PM 9/3/2003]

dman535

I am running the cam in my 77. I installed it after my Comp Cams roller set up came apart. I didn't know the fate of the engine and was not going to invest a ton of money into a cam if the motor was not going to make it. I also got an unknow quantity of metal in the engine and didn't want to get the metering portion of a hydraulic lifter clogged with debris. So that being said I went to my local engine shop and for $125 I got an aftermarket LT-1 cam and 16 colid lifters.

I am sure that there are higher power cams out there, but this one is very driveable, makes decent power and torque ( I advanced it 4 degrees when I put a new timing chain on) It also doesn't beat up the valvetrain as much as the super lift cams do. The idle is noticable, but not out of control.

One thing that did help was the 58cc Corvette aluminum heads. I had them worked over a bit and there was a jump in power and torque. Bigger cams tend to run better with more compression and given that this was originally spec'd for 11:1 it does help to have a bit more than the standard 9:1.

I adjusted the lash to .020 and .022. The factory specs are pretty loose and you can gain a little in lift and duration by lashing the valves a lighter tighter.

427Hotrod

I used it years ago and it really was pretty decent. Initially I stuck it in a 8.0 compression 350 with stock heads 9 new springs) etc with a Torker single plane intake, headers and a 750 DP. It idled well with a nice lope and would lug down to 1000 rpm in high gear with 3.36's and a 4 speed. It also pulled well past 6500 rpm no problem.

Then to make sure I won a race against a buddy, I installed a set of ungodly ported (by AFR) aluminum Bowtie heads. I mean they had tubes pressed in to cover head bolt holes ported through and all. They had 2.10/1.625 valves, titanium retainers etc, milled to 55cc and had been on an mid 8 sec nitroused race car. Seemed like a perfect match for my little cast piston small block...right?

Well actually they were, They had 207 cc ports after all the porting (up from 170cc) and ran like an animal with that old LT-1 cam and 1.6 rockers. It lost almost no bottom end and NEVER stopped pulling on the top end. It really liked 7000+ rpm ( new heads had killer springs on them!)

So the point of all this is, yes there are hairier cams out there, but for a street deal it is really very mild and will run well. If given good flowing heads like Vortecs it can really produce. It wouldn't bother me to run one again at all, and I've built lots of this stuff over the years.


JIM


PS- I spanked that '69 Shelby Mustang with a seriously modified 351 with roller cam and aluminum heads BAD!!