Hey guys i have a 89gta with a rebuilt l98 with new valve springs and i was wondering how big a cam i could go with because i plan on porting the stock heads and putting on some headers and a 3'' exhaust and porting the stock intake upper and lower. Thanks !

 

I think the best thing to do is to get on the phone with the technical department of your favorite cam maker and talk to them. I have found the best way to get the best service life out of all the pieces is to use the matching springs for the corresponding camshaft.

If you elect to get a bigger cam and use your new valve springs stay conservative with the specs because spring fatigue due to high lift cams will wear out you springs quickly. Worse yet spring bind can hurt you, but that is not as likely.

I use the TPIS zz9 camshaft in my 383 and am happy so far, not stock springs however!

Happy New Year.

 

from what i've heard and experienced - as long as the lift is under 500 most stock replacement springs are fine. - but then again not all are the same...

 

L98,

Welcome Aboard!

No cam is satifactory with the stock springs. Get them out of there. They barely control the valves with the stock cam profiles, and don't even do that very well above 4,500 RPM or so. I think the valve float was GMs idea of a governor.

If you're going to port the heads, another $80 for a set of decent springs would be a good investment. If you have to machine the spring pockets, the heads are already off anyway. Don't skimp at that point.

Incidentally, you ARE going to install screwed rocker studs while the heads are off, right?

And while the heads are off, you might consider installing larger valves so that the flow can be achieved with a little less cam lift. Just a thought.

 

Vader, My motor funds just went south and looks like I will have to use what I have.

What spring/cam combo would you suggest with the stock bore L98 , Team-g intake, holley 750, and Lt headers?

Would the comp xe274hr or xe282hr be too much for this setup?
I know the heads would not flow that good, but I should be able to get close to 350 hp shouldnt I?

I found out that my local machine shop could drill and tap for the rocker studs and machine the spring pockets for 100 bucks.

I need advice.

Thanks.

 

Just though I would bring this back.

Looks like I may have to do a cam swap and head work.

I dont know If I should just build my stock L98 heads (better spring, bigger valves, screw in studs and guide plates) or get a set of vortecs off my friend and have them worked.

I could always use the new parts out of the L98's in maybe some dart castings later.

What should I do, and what cam would be good with the stock bottom end and worked L98 heads?

Oh yeah, I have changed from TPI to carb. More info in the sig.

thanks

 

ttt

 

I put a zz4 cam in my 305 with 117,000 on the clock and left the stock spings in and it runs fine, only a lot faster up top.

 

Yes.