im looking at getting a new cam i just want something over stock what lift and duration should i look at thanks its for a 85 vette all stock do have a 52 mm throttle body for it also

 

I would look for a gross lift of at least .450/.450 with a duration around .280. The throttle body won't have any effect.

 

Go to LS1TECH.COM, then to the LT1 LT4 MODIFICATIONS BOARD. At the top of that Board is a STICKY that lists a lot of the most popular and best performing cams along with their characteristics (idle, etc.)

I'll bet you'll find what you're looking for there.

Wait, this is probably better.

http://www.ls1tech.com/forums/lt1-lt...ion-guide.html

Jake

West Point ROCKS!

 

Giving the OP max lift for the OEM heads would be helpful. That's one thing I think he's after.

I'm thinking most of the recommended cams on the LS1's board wouldn't work with the stock heads. Seems like I've read max lift is around .500" with an OEM setup.

If cam is the only mod, I agree a 52mm is unnecessary.

 

Instead of a new cam, which would have literally no effect on power output, you can try a set of 1.6 roller rockers. It's non-labor intensive, and will add roughly .028 lift to the stock camshaft - not to mention less friction on the valvetrain.

Ripping apart the block to swap in a different cam while keeping the same intake will literally do nothing for power, along with wasting time and money. Sure, you will gain a bit more low-end torque, but the RPM range will be the same and you won't feel any WOT improvement.

 

If increasing lift and duration with a cam swap will do nothing because of the intake, what is the point of adding lift (and some duration) with rockers?

To the OP, my experience:

The previous owner of my car did a cam swap and the car dyno'ed 230hp/330tq to the rear wheels. This was through stock TB, intake, rockers, ex manifolds, y-pipe, single cat (replacement) and cheapy aftermarket mufflers. I don't have the cam specs, but the potential to add about 15% is there. Crank rating on an 85 is 225 and my car put that to the wheels with just a cam. With an MR and NO other changes, 234 to the rear wheels. Your heads and exhaust will hold you back before the intake does.

 

It will be 1/4 the work of swapping in a camshaft, and rockers do not add duration to the camshaft. I was simply stating a cheaper alternative to his plan to increase lift.

It's true that exhaust will be better bang for the buck, then intake, heads, cam, etc. With stock intake and exhaust, 52mm TB will not make any noticable difference. However, if you get rid of the stock mufflers/cats, the rockers and TB will show improvement.

Unless you plan on porting or swapping intakes, it's not worth investing the $$ in a camshaft swap.

 

with Master Shake. For the $$'s and time go with the RR's. The cam will not do much for you with the stock heads which suck compared to current aftermarket. You would also have to do come intake work and exhaust work to receive any real power boost benefits.

I suggest that you read VADER86's web site and start making a plan that includes cam, heads, intake and exhaust.

 

That's not entirely true. You are correct that advertised/total duration remains unchanged but the .050 #'s typically go up about 2 degree's per .1 rocker ratio. Not only do the valves lift higher, they get into each lift height longer. It creates a more aggressive open/close profile. It also improves effective overlap (not timing of LSA).

I agree with the bang-for-the-buck philosophy, but a cam can still make some difference. Saying it won't do anything is misleading. But, I wouldn't pick a cam swap as my first move either. (or the second or the third.....)

As long as bang-for-the-buck alternative are being provided, I was surprised to note that an air foil can get a 48mm (stock) throttle body flowing higher than a 52mm. Google "MAF flow numbers" if you don't believe me.

I'd spend the money for a 52mm on something else -- until major changes are made.

 

I would agree that the cam change is unneeded now, and the 52 doesnt help. I would do the RR first, because those will work with just about anything you put together later, and theyre cheaper.

No way would I just put a new cam in it and do nothing else or have no idea what I wanted from the finished product. Thats how you end up with bad combinations.

But what really needs to be changed on an 85 is the intake/exhaust and heads. Research these first, then research the cams, then decide what you want to do and formulate a plan.

 

Well said Vader

 

So the point is that he won't waste as much time or money? I was simply asking you to think about the contradiction of saying adding lift via a cam would do nothing if keeping the same intake then, suggesting he add lift via rockers. If I were the OP I would be wondering "why do either then?"

Rockers add duration to the camshaft in the same way rockers add lift to the camshaft. I wasn't going to argue semantics...

GREGGPENN addressed the rest.

You should go back and reread your posts, they are quite contradictory and confusing, I'm sure, to someone trying to learn. If a cam is a waste without intake, I'm not sure how an exhaust is going to improve power and it costs twice as much. Though much easier to install...

For the record, I would not start with a cam, but if I don't have any other major plans (i.e. a few thousand dollars for intake and heads) I would definitely do one.

 

I am on my 4th iteration of engines so my experiance is until you get rid of the TPI intake, everything you do will be hindered. Start with a new intake like the MR, then decide how much horspower you want and state inspection you will have to pass and pick a cam, and heads combination. you do not need to change the throttle body, waste of money until 500 hp. At this point if you can get a set of full length headers. But until you get rid of the TPI you wont make a lot of horsepower. Dont waste money until you have a plan, then work to that end. Have fun......

 

Hi Mr Bonzia.
I have an 85 z 51 and 4+3.
I wanted to get as much out of the crap heads as possible and did some mods. As I am a novice in the V-8 engines because I live in Norway I sure had to have some advice. And people were very helpful and I am sure I bored people here with my questions.
Well I did get a new cam from TPIS the 700-134torque secrets with 221/231@.05 int/exh and .454 lift and 112 lobe sep. The car felt much faster but idle became a problem. HAd to adjust the min idle air. Put on Tpis coated headers and that felt good.Put on large tube runners from TPIS and for the psychological mater the first I did put on the airfoil which stands there now as it makes the air enter the plenum better. Had a new stage IV chip from TPIS and it was good but not matched to the mods. Got a new chip from Jeramy Formato who gave an exeptional good service. And the chip was matched to my mods and the engine responded good. I asked for an increased idle rpm at 850 rpm. This year I got Bosh gen III injectors from FIC who also is incredible with his good service. Now I am very satidfied with the engine and will dyno it later this year. Have an impression that I am just over 300 hp. Had to say I prted lightly on the heads and also ported the maniold.
But the best bang for the Bcks was the headers and exhaust catback
Good luck

 

I assume you don't realize how restrictive the L98 exhaust is, and I'm not looking for an argument, so please don't troll me into one.

I've had a cam installed in my motor, and it cost me roughly $600. They had to bring in a cherry-picker for it. Now, I plan on installing RRs myself, and it looks like a job even I can do for the small amount of hands-on experience I've had, so I would assume anyone that can change their own oil can install RRs.

'85 was a bad year with iron heads, and they were not designed to flow much more than .450 lift as stock, so with a pair of RRs it would be very close to that without having to dive into the block. If the OP is deadset on installing a cam, there's nothing we can do about it, but offering alternatives is something we can.

Edit: Also, when I stated earlier that a cam would _not_ improve performance, it may have been misleading. What I meant by that, is that the OP will not get the improved performance that he expects out of a new camshaft. Speed shops guarantee "40 more hp" out of this cam, but without supporting mods that 40 will turn into a 12.