I want to do a cam swap in my 88 GTA L98. I am gonna port and polish the heads and get new valve springs, now what would be a good cam suggestion, I don't want a rough idle, I want it to be more of a low mild. I am also going full catback with headers and a 2400 Stall Converter before the cam. I wanna pump out about 320-340 at the fly, just enough to defend itself against some of the big boys....THANKS...AARON

 

ZZ4 cam..... not a rough idle at all, can/will pass emissions and with aluminum L98 heads puts out 355hp carbed (probly 325hp with TPI on it).

 

well what if I don't have aluminum head...I have cast iron heads...will they still work.....AARON

 

The 1988-89 305 5-speed and 350 L98 TPI engines already have a pretty good grind from the factory (PN 10066049):

207/213 int/exh. @ 0.050"
.415"/.430" lift
117 lobe sep angle

For fast street work, looks to me like the factory cam in '88 and '89 is not a major detriment to power. Maybe a set of 1.6 roller rockers and stiffer springs, along with your ported and polished stock L98 heads, would be the ticket. I'm thinking of doing very similar mods to what you are planning, and I'll be keeping the stock cam. I would think the induction part of the equation would yield best results while still keeping a good idle and that mountain peak-like torque curve in the street RPM ranges.

Dave

 

I too have been thinking of a possible cam swap, but want to maintain my stock idle quality & great torque. I have been considering the ZZ4 cam or maybe one of comp's 210/215 - .500"/.510" - 114 LSA hyd rollers. But more & more I am beggining to think like Dave there. This stock 89 cam has more duration than any of the LT1's and they rev pretty good. With some 1.6:1 RA's about the only thing you're giving up is about .030" to .050" lift & there is still the difference in LSA's. I'm thinking that the rocker arm increase should give over half the gain of the cam swap with a much smaller fraction of the cost & labor. Personally, I'll save the cam swap for when I have to do a rebuild.
I've got some 1.6 Roller tip rockers on the way. They are cheap ($74) CAT brand and are self - aligning. They look just like Comp Magnums in the pic. I've used some of CAT's other parts in the past and their quality has always been good. I know their $50 underdrive crank & alternator pullies sure helped my car alot.

 

Yep I noticed that too - the 1988-89 roller is the most aggessive hyd. roller used in any year f-body to date. Even the LT1 cam does not have as much duration @ .050". Just my opinion, but for myself that factory 207/213 is enough to get the job done on the street and some occasional track work, esp. with a long runner intake. Its interesting to note GM put a new hyd. roller grind in the '90-'92 TPI:

(PN 10111773)
202/207
.413"/.428"
114.5 LSA

So I guess just the '88-89's got the 'big' cam.

Dave

 

Just to add in to what 350Formula mentioned, I'm thinking of the exact same thing with regards to running 1.6 rollers with the stock '89 207/213 cam. Seems to me it would make for a great street combo with a lot of torque and still maintain great (factory) driveability.

Dave

 

I've got an 87 L98 in my GTA. Is there a difference between this and the 88-89 version? I was under the impression I didn't get the peanut cam...just the 5.0 autos did. What's the deal?

 

The deal is you're right, you don't have the rollerized version of the 'peanut' cam, which came in the 305 TPI auto. cars that year.

What you have is:

1987 350 TPI roller cam
PN# 14093643

202/207
.404"/.415"
114.5 deg. LSA

Although not the exact grind, your cam is close to the LT1 grind in specs. All in all, a good high torque grind without the brutal stifling of RPM's the infamous 'peanut' cam brought to the table.

1987 hyd. roller 'peanut' cam (305 TPI auto trans):
PN# 10088155

179/194
.350"/.384
109 LSA

The 350 TPI never came (thankfully) with the 'peanut' cam in any year.

Dave

 

I'm assuming that's why there was a performance difference between 87 and 88? besides the belt change of course. hmmm....it may be time for a cam change. I've thought of running the LPE 219 with my stock heads. Think this would be driveable until I can get the heads heavily worked over?

 

The LPE 219 is for a modified engine with better breathing intake, a converter, and ported heads or a better flowing aftermarket head, just my own opinion here. Before I would do a cam swap I'd figure out first what the intended purpose of the car is. In my own case, I'll keep the stocker cam because it delivers tremendous torque right up through the mid-range RPM band. My car sees a fair amount of city driving and some highway commute, and the stock cam has a ton of torque right where I need it. Going any bigger in my case would mean losing some bottom end to gain a bit higher up in the RPM range; and I really want to keep all of my bottom end.

I would look at your intake tract, maybe add 1.6 roller rockers and a good exhaust system before yarding out the cam. If you add the rockers and have original valvesprings, it might be a good idea to install fresh stockers or maybe LT1 springs to guard against premature valvefloat with worn stockers.

Dave