i have an 86 Z lb9 and i want to get into the 13's. I have a 3 angle valve job on my heads, this is my cam . Its an automatic and i have a 2000 stall converter on it. I have a 2.73 gear in the rear. I also have a 2.5" dynomax cat-back and a high flow converter. The direct fit hooker aerochamber i ordered/installed has a 2.25" inlet into the muffler. How bad is that hurting my performance because now i feel like i am running maybe high 14's at best. The tires will barely chirp if i stomp the car from a stop. Thats also with 225-60-15's which is a farley small tire. I gutted my air boxes as well. Also i just performed a tune-up on it so im not concearned about that. In conclusion i am asking what is needed to put my car into the 13's? I would think with all my mods that i would already be close but im nowhere near. Does anybody else think i should already be there? If not what should i do to reach that goal. If so, what is holding me back? (2.25" inlet at muffler maybe?) I have no other source of information about these cars except this board so thank you.
PS. assume all things i didnt mention are stock, ex. manifolds

 

What are you running? Take a look at my sig to see what put me into the high 13's. I would say that the 2.73 gears are not helping at all. That is why you can't even chirp the tires. The 2.25" exhaust is definitely hurting you. Why did you go with a 2000 stall converter? That's only 400 higher than stock. I hope you didn't pay too much for that mod. I am running a 2800 stall and it is really nice when I can keep it from locking up, but that is a different story. I almost wished I had a 3000 stall.

 

The tci converter was a gift to me as well as the tci 700 tranny i got in it now, so i wasnt about to turn it down. What kind of gain would you think i would get out of going to a 3.42 rear as well as porting the plenum?

 

I'm not sure about porting the plenum. I don't think it would help much unless you did the runners and intake manifold. But I'm not sure. I would like to hear from anyone that has done it as to what kind of gains they got. You would not be disappointed in switching to the 3.42 gears just for the reason that it will make the car a whole lot more fun to drive around town. It gets up through the gears a lot quicker so at the track you will reach third gear much quicker. On the 2.73 gears you probably wouldn't get out of 2nd gear at the track.

 

I just read you first post again. No headers?? You gotta get some headers and a new exhaust system. I would get a 3" Catback. Make sure it is a good free flowing catback. Stay away from Flowmaster because you will need all the power you can get and the Flowmaster is too restrictive. I lost around 8 RWHP compared to the catback that I have now. The one I have now is a good one. The Dynamax and Magnaflow systems are also good. I have not dyno tested the Hooker but I have heard good things about it. I really depends on your budget as to how fast you want to get to the 13's.