I have a 1991 Z28 5.7L with apprx 162,000 miles on it (still runs too). I have a 2002 SS that I am thinking of selling to try and get top dollar for it before the 5th gens come out. Im looking to using some of that money to fix up my 91 Z but dont know where to start. 1. How much does it cost to rebuild the motor stock versus how much to upgrade the motor (meaning boosting horsepower, changing the heads, crank, changing the cam etc.) 2. Since the stock numbers for the stock 350 is 245hp from the factory, I would be happy upgrading it to 300+hp. How much do you think that would cost and what would I have to do? 3. If I upgrade the motor, would I be able to still use the stock TPI or would I have to change that too? 4. I'm looking at spending around $3000-$5000 for this drivetrain rebuild. Is this price range acceptable or am I out of my mind? 5. Also, any reputable pony car shops in northern california. I live in SF and Im willing to drive to a good reputable shop. And how much does it cost to rebuild the rearend? I rebuilt my 700r4 transmission for about $700 5 years ago so I have an idea on how much the trans rebuild will be. Thank you in advance for any help and advice you can give.

It depends on how much you want to spend on a stock rebuild. You can go from mild to wild.You can keep the stock TPI but they are a little restrictive you could do the LT1 intake,mini ram........ And to be honest if you want to keep the 10 bolt rear end you are better off buying one out of a 4th gen $250-500 would be alot cheaper than a rebuild.

Hey Chevyowner02, thanks for the advice.

No need to change the crank. Changing the heads and cam will about double the cost over a stock rebuild.

The big cost will be in the TPI and exhaust upgrades to support that kind of power.

You will have to change just about everything about the TPI. $$$'s.

For the engine & exhaust, you can probably get there.

PM Kevin91Z. He's completely familiar with what it takes to make power and keep California smog happy.

Using a 4th gen rear doesn't make a lick of sense. It's the same thing on the inside, and two inches wider, requiring new rims with more offset. Figure on about $350 for gears, bearings and install kit, $250 for aftermarket axles, $150 for an aluminum support cover, and about $200-$300 for labor. There's a tech article linked from the thirdgen.org homepage about beefing up a stock rear.

I Agree... its not worth doing a rear end swap. I have 350 hp and a slightly modified rear ( just better axles) and its soild. If I were you I would consider doing a motor swap. I like brand new things and rebuilding just seems to never be the same as a new motor. Defn condsider a Mini ram or something along that line.

It dose to me for all that money to rebuild it and the down time it would be cheaper and quicker to they are not any stronger but it would be quicker,cheaper. I thought you could use stock rims on the rear? Mabey with drums.

If all you want is a gear change or go from open to posi, get a 3rd gen rear axle with the gears and carrier you want. Still doesn't make sense to get a 4th gen rear.

$1050 for a rebuild vs $500 for another ticking time bomb If he wants to stay on the lower end of his budget thats 1/3 of it for a rear end that might/might not hold up.

A stock, unmodified $500 4th gen rear is more of a timebomb than a $1k upgraded 3rd gen rear.

300 HP isn't that hard for an upgraded 3rd gen rear to handle.