Originally Posted by Granny'* Delta
I could upgrade rockers and get a little more lift I suppose.
Any idea where I can find the list of RPO codes to figure out what my gear ratio is?
This car does not run too bad to begin with. The original owner was my grandma, and it was fairly well taken care of. Its definetly a LN3, but its got what are essentially steel headers on it that was supposed to come with some earlier version of the motor.
With a L27 Intake Swap, CAI, Cat Delete, and 2 1/4" free flowing exhaust what could I expect to run in the 1/4 mile depending on my gearing?
Not sure if the throttle body will bolt up. Is the 89 LN3 also MAF based? Are the throttle body sensors the same?
1/4 mile might be in the mid 16'* if its running right. I ran a 16.1 in my 95 L27 Regal with 1.8 ratio roller rockers, open exhaust, CAI, and no resonator.
You could upgrade the rockers, but its a dumb idea IMO because the gains are not worth the price. The only way rockers will benefit you is if you are running a Series 1 L67 (Supercharged version) with the Eaton M62, and you ALSO port the heads and intake manifolds. Otherwise, don't expect much of anything on a N/A Series 1 3800 with rockers because the just isn't enough flow.
If you really want to go faster with this motor, the first thing you will need to do is pull the heads and port them. I did this with a dremel and grinding stones and I can provide pictures. You're mostly porting some of the exhaust ports to remove the exit ridges you'll see, widen the bowl a bit, and smooth out the rest of the exhaust port, while keeping it a D shaped port. For the intake, you'll be removing casting imperfections that restrict flow and cause turbulence. There are a *lot* of serious casting imperfections, and the bowl itself is a big restriction point that you can widen at least 1-2mm safely so long as you don't touch the valve seat. This is the biggest problem with L27 heads with regard to flow.
Pictures to come for those who are interested. Porting these heads, with the roller rockers, and with a port matched intake manifold pushed me over to 92% injector duty. My wife even said she felt a huge difference, especially off the line.