first off i searched for 1 1/2 hrs and was not happy with the results i obtained so here is goes

i have a 88 IROC L98 that is my daily driver (when the snow goes away) that im looking to mildly upgrade perf in. it needs new valve seals (suprising huh?) and i thoguht this would be an oppertune time to upgrade it a little bit. it has about 110K on an all stock motor and i checked it with comp. tester and all cyls were rather even and around 160-170 if i remeber correctly, it was very well maintained so i dont beleive i need to do anything with the bottom end.

first off im looking to pull the heads and have them recon'ed, just like faced like .002-.003" to make sure they are flat, valve guides if it needs them, checked for cracks (where are cracks most common on those heads?) and a 3 angle valve job. i am looking to do a mild pocket porting and polishing the combustion chamber. also i was thinking of gasket matching the heads and the base (and gasket recommendations?) lastly i was looking to run the steel shim gasket to bump compression a little.

what kinda of valve seals should i run becasue i have heard (and seen) the original factory ones like to crack and leak and i want to prevent this from happening again.

is there any room to do any work on the runners? i know there is alot of clean up that can be done to the plenum which i plan to do.

i have an AFPR in a box that i havnt had time to put on, and also i was thinking about getting a cam. i found in my search that alot of people like the ZZ-4 cam and found them rather cheap. where in the powerband does that cam really come in? do i install it straight up or adv. or ret.? and also valve springs should be replaced but which ones? i was thinking of running ZZ-4 springs then they should match the springs and are rather cheap also.

im also going to replace the timing chain and oil pump while it is out of the car.

oh the car had hedman shortys and y pipe and a slp loudmouth style cat back and hollowed cat, and factory 9 bolt rear and 3.23s and the T-5 swap thanks

*eric*

 

Sounds like you did a lot of the things I did. I didn't port my heads at all though.

As for matching the manifold and heads, I'm not sure if the gain is worth the work. ANYTHNG is worth something to someone, and I guess it's a personal thing. I know I'm upgrading in the not too distant future so I didn't bother with it. That doesn't mean you shouldn't do it.

The ZZ4 cam has worked out great so far. Installed straight up, no advance other than what's ground into it. LT4 springs. Obviously ZZ4 springs will work just as well. Get screw in studs while you're at it. I'm still running a factory tune, and she runs just as good as the day she rolled of the line. I had to add a few degrees of timing, that was it. That being said, I guarantee theres a good bit of power waiting to be tuned in once I get it done.

My powerband jumped up about 400 RPMS across the board. Lost it at the bottom, gained it at the top. Obviously there's a good bit more power too. I also have headers and exhaust, which really should be a given if you're gonna dig into the heads and cam. With my stock torque converter and the 2.77 rear gear, you could really feel the lack of low-end. It was still VERY driveable, but you could tell it wasn't optimum for performance. These mods (and my new driving habits) ended up blowing my 170k mile trans, and I got a deal on a performance built trans from a friend with a 2200 converter. BIG DIFFERENCE, although Ideally maybe a tad higher stall would be ideal. (2500?) I still have the 2.77, but the the 3.27 axle is waiting in the back of the truck as I type, and I might even get it in this weekend.

Well worth the cost of admission, but as a TGO member once said back when I was researching this..."after bolt ons, there's no such thing as just ONE more part".

Amen to that brother!

 

Ahhh, exactly the reason I stepped up a cam size over Comp Cams recommendation.
My L98 heads turned out to be cracked after I had them magnafluxed, but they were repairable. I had them 'pinned' where they drill a hole at the end of the crack, screw a plug into it, and surface the heads flat. This is a pic of my head. The arrow points to where the pin is (you can barely see it, it's darker colored). The crack started at that bolt hole and was running toward the combustion chambers.