Hello,

I recently purchased an 84 Corvette from a local dealer near my hometown. It was a good deal IMO, as it only had 69K miles on it, and he let it go for $2,600 with taxes included. I knew going into it that it would need some TLC as it sat outside from 2017 till basically the moment I bought it. Anyway, it has a leaky trans seal and leaks ATF constantly. Over the next few days or weeks, I was going to drop the trans and replace it.

My first question is, what else, if anything, should I do while I'm under there maintenance-wise? I'm planning on replacing all the main seals on the trans since it's out. I also plan on getting a new Delco filter and fluid, but should I look for or do anything else? I'll have it on a Quick-Lift so I can pretty easily do anything.

My second question is about performance. I've heard mixed things about modifying the 84 due to its crossfire injection design. From what I understand, I will have to remove the starter and exhaust to drop the trans. If that's the case, I wouldn't be opposed to replacing the exhaust and doing the headers while I was down there. The main thing is, is it worth the time and money to pursue these upgrades with the stock crossfire intake? I know they used to make the Renegade intake, but those aren't viable as they aren't produced anymore.

My third and final question is regarding the fuel pump. I've heard that after 85 they switched to a newer fuel pump and that it could be worth upgrading mine. The thing is, I have a used AEM 340 LPH fuel pump already that still works from another one of my vehicles. Does anyone know if I could use this as a replacement instead? I'm new to the Corvette scene so I'm not sure. I do highly doubt that it'll work though, but I figured I'd ask since I already have it. The part number is AEM 50-1215, and it has no listed applications, only universal fit.

The fuel pump ties into the exhaust. If it will fit, and I get the exhaust and headers, would it be worth it? How much power, if any, do I stand to gain. If there is anything else you'd like to add or ask, don't hesitate. I look forward to hearing your thoughts.

 

I like CFI, but what do I know? Yeah, we aren't making the Renegade right...now. The 340lph pump is WAY overkill on a stock motor IMO. I run a 255lph pump on my current motor, but it isn't stock either and runs just fine with that pump. You would be much better off installing the AC Delco 85-87 corvette TPI pump for sure and just set the pressure at 13psi and forget it. GL

 

Maybe replace the diff fluid and include the factory friction modifier that is needed. Fuel filter should be changed as well.

Headers and a free flow exhaust will always be worth it even on the Cross Fire... A small bump in horsepower anyway. Eliminating the cat or replacing with a high flow one would be advantageous. With exhaust improvements you will get a nice improvement in sound with a little rumble. I believe a fellow forum member has an interest the Renegade intake and may be thinking about manufacturing them again, not sure.

Not too sure about the fuel pump, which is in the fuel tank, but remember a good flow and pressure is knocked down to the needed level at the fuel pressure regulator.

As far as performance upgrade and fun factor is a looser torque converter something in the 2,200 to 2,400 rpm range and rear gear ratio of 3.33:1 to 3.73:1, I prefer 3.45:1 to 3.55:1 as the first gear ratio of the 700R4 is very high and leads to tire spinning on launch.

Top quality oils, plugs and wires, a K-n-N air filter, a high output coil wouldn't hurt, a little timing adjustment and I would pull the valve covers and install 1.6:1 self aligning roller rockers. If you wanted the intake can be gasket matched and lightly ported. These are things that are done to 84's without digging into to far into the engine... with only 69k miles I would only worry about the timing chain and if it has the plastic gears and maybe valve seals.

my 2 and a half cent contribution... Congratulations and welcome to the Corvette World, keep the wave alive when you cross another vette... lol, Cheers...

 

See the Master knows!!!

 

For me the biggest restriction on a stock crossfire is the exhaust. headers and free flowing exhaust would help. after that its better flowing heads and porting intake manifold.

 

exhaust, fuel pump, and purchase an intake manifold that has been ported.

 

Welcome to the forum and the madness! Re-new all the fluids so you have a baseline. Check the date codes on the tires. If it has been sitting for years, they are probably aged out. Drive the car for a while before you make any dramatic changes. Get to know it.

 

Sitting that long, I'd just about bet the vacuum lines are gone if they are original too. They are cheap enough to replace them all when you buy bulk lengths @ the parts store.

 

Tires are def on my to-do list. I already looked at them, and they have a little dry rot starting to form in the tread. I plan on getting everything sorted out mechanically before dumping money on the tires though, because I want to buy a nice set. It already has all new fluids, except one reservoir of brake fluid which I'll get to eventually. I'll check into the vacuum lines. Are there a bunch of them?

Anyways, thanks everyone for all your feedback and input.

 

If you have the stock rims you will be surprised that hardly anyone makes a P255/VR50-16 tires... with the 16 x 8.5 rims the P245/VR50-16 (Like $430.00 for 4 at Pep Boys) is readily available for the front. If you have the 16 x 9.5 this is where the problem comes in. Michelin recently ran a production of the 255's, they are some of the most sophisticated tires on earth and being that the 84' is the best handling C4 they would be an awesome upgrade but at $2,500.00 plus for a set of four, I would have to get a second mortgage! There are good tires out there just the size issues, thus many upgrade to 17 inch rims from later C4's and many C5's and later models... Keep us updated on how it all shakes out and welcome again, Cheers...