<BLOCKQUOTE>quote:</font><HR>Originally posted by sar_moby:
Ken- Many thanks!
Ok the 9C1 has a L98 cam. I believe a LT4 is similar and should work well w/the L05.
A few questions in the event that I commit to some changes to the motor.
1.Are new roller lifters req'd? Springs?
New roller lifters? Not likely, unless you have a really high mileage engine. It's always been said that the lifters should always be changed when doing a cam swap on a flat-tappet lifter engine --- but that's not the case on a roller lifter engine.
Springs? I'd say yes. They are relatively cheap, and you will be going with more lift so it's better to have springs suited to the job, either using GMPP or aftermarket. IMO.
2. If I pull just the intake manifold (currently leaking a little coolant) to swap to the LT4 cam, timing set, rockers(?), lifters(?) what other mods?
Rockers? My suggestion to others that are budget minded is to wait on changing the rockers because that can be done ON the car later, as money permits. Or opt for the inexpensive self-aligning stamped steel 1.6 rockers (around $65 for a set).
Other mods at the same time? Go to http://www.thirdgen.org
and check out the ultimate TBI mods including the adjustable fuel pressure regulator (FPR).
[B] port the manifold? and/or switch to the Holley TBI?
Look for any casting flash in the manifold and clean it up with either a Dremel or with a file. Holley TBI? Nah. If you do anything, use the higher rated injectors. If you need more airflow later, you can always either bore your TBI for the larger throttle discs OR put the Holley on. See the TBI archives on Thirdgen for this type of info.
3. what are the exhaust differences LTZ to 9c1?
, the 9C1 gets the bigger Ypipe, and a lower restriction cat. I don't know if the LTZ gets the same. You'd have to check the Bcar Parts Bibles, or call and ask Dal.
Or maybe someone here knows (?)
4. Has anyone done any air flow work on the stock heads( not Vortec) to increase HP?
On a Bcar head, dunno. On an Fcar LO3, yes. The links are at ThirdGen, and well worth seeing how they did. Did it help? Yes. Was it as good as going with either Vortecs or aftermarket? No but a very good learning experience, and for the truly cash-strapped (or married
), possibly the only way to go <g>. IF you wanted to stay cheap, then you could do all the easy cheap stuff suggested by Vizard: back cut all the valves, use anti-flow-reversion rounds on the valve lip, and some basic pocket porting. That's all "free" torque and hp you free-up. You'll feel the difference too, but not by as much as by using stock untouched Vortecs. So it boils down to a cost choice, and a question of how much more performance you want.
If you want nothing more than exceeding the base 9C1 LO5 (205 fwhp, 300 fw ftlbs) up to the 220-230 range, then the cam, TBI, exhaust, cold air intake, and head cleanup will be enough... and maybe even a whisker more.
OTOH, if you want a solid and easy-to-get 260+ hp and 330+ ftlbs, then you want ***at minimum*** a cam equal to, or above, the Bcar LT1, the Vortec heads, and TBI mods enough to provide the fuel needed to match the airflow you'll be getting. HTH. - Ken