Car is a 91 Z28. auto. 2.73 rear. I like the 2.73 (I take the car on a lot of road trips)


383 with AFR 195cc heads . Compression should be about 10:1. I am ordering the cam now. Looks like it will be a TPiS zz-9 with comp pro magnum roller rockers. Unless I can find a TPiS big mouth intake and runners I will have the stock intake extrude honed and polished. Car will likely have Dyno Don headers and a single 3" cat back. No stall on the converter. Think it will get in the 12's?

 

Not with those gears

 

Mismatch. The ZZ9 cam revs high, it needs to be stalled well (3000+)...

Won't see 12's without some form of stall speed...

 

ok. is there another cam that would get me there or is a stall conv
the only way?

 

12's is hard if naturally aspirated. It takes cam,heads and different intake, converter and gears. Unless you use a sc or nitrous

 

Your rear gears aren't the problem, you can simply run a taller tire in the back to alter the final ratio, so stick with the 2.73's and run a taller tire out back when your racing. However, your still going to need some form of stall speed converter to make it into the 12's though. Your trap speed will definitely embellish how fast you want to go, but with ET though, it's all about the launch, and power braking a stock converter that stalls around 1500-RPM simply won't cut it. You may get it to flash where you need it to, but in my opinion it's not going to be enough to get you there...

Try though, see what happens...

 

ok, we will see and if its a no go... then onto a stall conv and gears if needed.....

 

If you're intent on sticking with those gears, I wouldn't even be thinking about the 12's or any ET goal. That engine/heads with something like a Comp XE 218/224 on a 110 or 112 LSA would be a strong cruiser with that stock TC and gears.
Sure you could step up the TC and get a 12-sec timeslip, but without a gearing change to go with it, it will be annoying at every takeoff where you don't feel like blasting it.
The most I would do with those 2.73 gears is something like an S-10 TC. It would flash to 2500+ behind that 383 and still drive very near stock.
If you really want to take advantage of those heads, valvetrain, and exhaust that you're investing in, and still keep it mild, then consider a Yank SS3200 TC, 3.42 gears, and an XE 230/236 cam (that is, IF you get the different intake; for stockish intake, stick to the 218/224 cam).


StreetLethal, think about that comment above. For the equivalent of better gear reduction, he would want a shorter tire, not taller

 

That is absolutely correct, must have been having a moment lol...

 

I see snapped rods, blown trans or shredded U-joint in the future if engine is beefed up and those 273 gears are kept. Too much strain on everything

 

I agree with pretty much everything that's been said. I guess in the end, I would need a different cam for a 2.73 rear v. a 3.42?

 

3.42 is better but your still gonna need a 3000+ stall to take full advantage of that cam.

 

12's in any "stock" car is hard especially with gears in the 2's. Gears & the converter will get you there the easiest. If it were me, I would find a 3:45 or 3:42 9 bolt that you could pick up for $300 and just swap it in - keep your 2 series rear for all around driving. Like others have said a 3000 stall will help too - I would do those & see where you are before I opened up the engine and started buying expensive head/cam & other parts. Practice makes perfect too - work on your launch - small gains in your 60 will be big gains at the end of the track!

 

When I was still running my long-runner TPI I found that it made gobs and gobs of torque at the line. Hooking up might be your biggest problem. You're going to want some good tires if you want to take advantage of that torque. I'd look at some drag radials if you plan to also drive it on the street. If you're still spinning look at suspension mods, and the gear/converter change. I'd also suggest looking at the DIY PROM board for help with the tuning aspect.

If the weather is just right, I think you'll dip into the high 12's.