tgates

i have a 91 z28 5.7. im about to buy a lt4 hot cam to have installed. is there any other parts i need, besides the cam to be able to make this work?
i have bigger injectors already install and other bolt ons

StripedFomula

while things are off, i would upgrade valve springs (sorry cant help with what kind), put on a new waterpump, maybe put on a nice timing cover. and while the valve springs are off i would put on new valve stem seals

tgates

ok thanks

BigBadLou

You don't need any other parts.
But like StripedFormula pointed out, you can always benefit from the state of disassembly to swap other parts.
Yes, springs and seals would be one thing I'd definitely do.
Roller rockers would help pick up some lost power as well.
Double roller timing set is always an improvement.

Of course, I don't think I need to remind you to check all the lifters and pushrods while you're in there.

I just realized one important thing: you will probably need to adjust the VE tables on your chip if you're doing multiple modifications to the engine's airflow.

Hope this helps.
Lou

tgates

thanks lou, everything helps.

BigBadLou

Just remembered: you'll need to check the maximum valve lift on the stock L98 heads (I can't recall the L98 heads specs right now). If the LT4 cam exceeds that lift (or you install 1.6 rockers), you'd need a small modification to the heads to allow for more lift.

It's better if you find out for yourself than rely on a shop and have them screw it up (for your money). Like my mommy used to say: "don't trust strangers".

Lou

tgates

thanks for the look out lou, i planed on getting 1.6 rockers. are you saying that the 1.6 rockers will prevent me from having to adjust my heads for the lift? or do i have to do that no matter what.

tgates

or do you think there is a better CAM to go with?

ayers1967

Yes , There is allot of cams out there now that is better and will work for you. The hot cam is 15 years old or more. if you do use that cam I would install the comp cams beehive spring . If i were you I would go to there website and fill out the cam recommendation form .

BigBadLou

The answer isn't simple. It really depends what you expect from the engine.
There are dozens of cams out there suitable for your engine, you just need to review their specs based on what goals you have in mind for your engine.

Example: if you are staying with the stock TPI intake, there's no need for a racing high-RPM cam because stock TPI doesn't work well above 4500 RPM anyway. For a good street use, a low-end torque cam would be more beneficial (let's say ZZ4).

Btw, if you go with 1.6 ratio rockers, you WILL have to get new springs and machine the heads (the valve guides) to allow for extra lift. But if the heads are off for a valve job and milling anyway, it would be a very good time to do so because it's a very inexpensive job and doesn't take long.

But like I said, you need to consider your long-term goals for your engine and select a camshaft based on that.

Hope this helps.
Lou

tgates

well i intend on putting in a holley stealth ram intake along with a cam this spring, im just getting all the parts together now.

what im going to do in the spring is alot at one time, such as
-58mm throttle body for the HSR
-3.73 gears
-Hooker headers with an offroad y-pipe
-lowering
-tieing the frame
-Cam
-im getting a progamer installed into my ECM so im able to get it dyno tuned

i have everything already expt the ECM /cam /HSR.

Oh yeah and i plan on doing the t56 swap whenever the time is right, so im steard away from a stall converter

my aftermarket parts now are-
-BBK under drive pullies
-true ram air with K&Ns
-MSD cap, rotor, coil, wires plugs,
-adj fuel pressure regulator
-ported plenum
-air foil
-jet sage 2 chip
-high flow cats
-exhuast cut out
-upgraded injectors 27lb

Im kepping it N/A for the most part, all this is to give a basic idea what im doing. basicly just a stock LOOKING street car, not sounding lol.
i hope this information helps you guys think of a good cam that would be good for my set up.

BigBadLou

Now that makes a big difference. By putting the HSR intake on the engine, you'll destroy its low-end torque that the TPI is famous for and of course with that will go the economy so don't expect to see anything close to 20mpg, morelike below 15. Provided that you even TRY to keep your foot out of it, with the new-found power.
I'd look into other people's builds and see what cam they used with the HSR and what their dyno numbers look like, that should give you a good idea on what to go with.

I assume you already know that once you put the ECM programmer in, you can remove the Jet chip and AFPR.

I'd think that you would pull the heads and work on those a little as well, every little bit helps, especially since those will be the biggest restriction in your engine after all the modifications are done.

Sounds like a nice project!

Lou

tgates

thanks lou, and yes i know that need to get rid of the chip, and im not worried about my mpg bc its just a weekend car lol.

i dynoed the car as it sits with the bolt ons listed and it put down 247 whp and 342wtq not tuned, im hopin to get like around 320-330 by summer with a proper tune.

texas97z

I had an 89 rs I swapped a 355 TPI into. Later went in and added the hot cam. While I had everything off I did the siamesed runners mod, gasket mateched the plennum, gasket matched the intake side of the runners, ported out the middle of the intake manifold(where the pinch is inside the port) and gasket matched the the intake ports where they meet the heads. A lot of work, but my moto has always been I have more time than money and if I can do it/make myself, I will learn how and do it.
I did loose some low end torque, but still had more than needed to get me out of the hole and pulled pretty good(better than stock) up to 5,550 rpm(car was a 5 speed). I just bought the cam from summitt, then purchased springs and the 1.6 roller rockers seperatley off ebay. I went with scorpion rr, and the springs were good o .600 lift with 130 lb pressure closed at stock installed height, sorry I don't remember more details on the springs.

The thing I will warn you about is the rocker studs. This cam will pull the pressed fit studs out, even the ones that have the pin pressed though them. So while you have everything off, convert to screw in studs if you are going to run th 1.6 rr. I didn't run mine with stock ratio, so I am no help there. But even at stock ratio with the hot cam springs which have less seat pressure I believe then the ones I bought, you will still be cutting it close as the lift is .492/.492 @ 1.5 ratio. Hope this helps.

Josh

Kevin91Z

I would not bother putting an LT4 hot cam in an engine with stock iron L98 heads. Its like trying to put out a fire using a straw. You will have to do so many mods to the stock heads to make them compatible that you will spend almost as much, or more, than a set of used good aftermarket aluminum heads such as Trick Flows.
The biggest cam that is compatible with stock heads is the Comp 2032.