mpilarZ281992

OK, as the name implies I got a 350 TPI in 92 Z. I mod the intake with ported plenums, SLP runners, foil the 48cc, free mod with cold air induction.. the exhaust is done with hedman shorties, new cat, ect....so now im looking into internal mods. I was going to go ZZ4 and loose my L98 (but it only as 15K--got it new from GM couple years ago) but I spent good money and wanting to save now. I was thinking a moderate cam... what recommendations should I do for under 2 grand. Thanks for any info (im still quite ignorant on internal mods).

1987IROC350

I would seriously just put a S/C on it. That way you could always easily remove it to return to stock.

I'm not sure who still sells them. I looked around a little. I thought Vortec made them for '88-'92 TPI cars with the serpentine belts.

mpilarZ281992

I've looked into S/C. Yes Vortec makes one as well as Procharger, but they are 4 grand new. I know Paxton in the past made them, but I believed they had some problems. Im sure they would give good power, but Im actually looking into internal mods. Thanks.

1987IROC350

I have the LT4 Hot cam which has a nice slight lope. But if you can get away with a more wild cam I'd do it. My car had the L98. But I replaced with a complete Vortec TPI engine. It came with the Hot cam.

Hot Cam specs:

Cam Style: Hydraulic roller tappet
Basic Operating RPM Range: Idle-6,000
Intake Duration at 050 inch Lift: 218
Exhaust Duration at 050 inch Lift: 228
Duration at 050 inch Lift: 218 int./228 exh.
Intake Valve Lift with Factory Rocker Arm Ratio: 0.525 in.
Exhaust Valve Lift with Factory Rocker Arm Ratio: 0.525 in.
Valve Lift with Factory Rocker Arm Ratio: 0.525 int./0.525 exh. lift
Lobe Separation (degrees): 112

The kit comes with lot's of other stuff you need.
http://store.summitracing.com/partde...2&autoview=sku

Here is a vid of my car.

http://www.youtube.com/watch?v=t1eNVPr0pkg

86camaro383

Thats simple. Heads and cam. When its all said and done, You wont be able to S/C for under 2k. Get some AFR's and a nice cam.

What headers/exhaust do you a have?


All in all, 3rd gens heads and cams are way to small, and exhaust is way to restrictive

Kevin91Z

Did you change the intake manifold yet? Edelbrock makes all the TPI ones now and their manifold is the best price.

Some testing we have done in my local club has determined that the area by the injectors is the smallest part of the intake manifold. Porting that area, and gasket matching the openings to the heads and to the intake runners will give you the best gains.

A cam and head swap will come very close to your $2000 limit, if not push you over it. And before you do a cam swap, you need to find someone who can do custom computer chips. Our car's stock programing does not like big cams.

AutoRoc

There's nothing special about a ZZ4 engine. It has aluminum versions of your L98 heads. You have a good list of starting mods....As I always reccomend, the following is my favorite recipe:

3000-3200 stall converter($500-800)
MIckey Thompson ET Street Radials (245/50/16) $400
100 shot of nitrous. ($700)
Spohn Lower control arms($120)
Spohn LCA relocation brackets($65)
Spohn LCA Hardware Kit ($11)
Comp Cams 1.6 rocker arms($225)

If you still want to crack open the engine, I'd do 1.6 roller rocker arms, no more.


You didn't state any power or timeslip goals so I guess this is just a fun street car. I don't reccomend doing a bigger camshaft because the gains are not great for the money and time spent. You'd probably also need new/bigger valvesprings, etc. Money was already spent on the intake so I wouldn't go dumping more into an aftermarket intake. Changing the cam would probably also require changes to the tune/computer which isn't a walk in the park, or cheap. To keep it simple, Tires/Converter/100 shot will keep you smiling. Instead of a "mild" camshaft, I'd rather take some weight out of the car. Rear seat, front swaybar(unless you like highspeed turns).

Goodluck!

mpilarZ281992

Sorry for the delay in response. No, I have not changed the intake manifold at this time, though if I was considering over >350HP i definetly would. The exhaust is quite simple, but basically shorty Hedmens, magnaflow cat 3" (done away with dual cats), to Monza tips. I will replace the Flowchoker soon (prob. magnaflow). I do agree I need a AFR, thats a good idea.
I reviewed the Vortec TPI engine, and looks nice.....but I was considering the engine I have now since it only has around 10K miles on it (bought it new a couple of years ago from GM)--my initial idea was to keep it as original as possible but that soon got boring. Thats why I wanted to go internal on this one (to reduce cost). I like AutoRoc's idea on replacing with 1.6 roller rockers...a larger CAM swap would seem costly at this time. Also the 3000 stall converter looks reasonable. Question, what stall converter would be a nice fit? I looked into these and seem confusing. Also, Im afraid of busting up my nonmod engine with nitrous--not sure how much L98 can handle?