First Mods for an Iroc z

[L2R]

Well I am really close to getting my first Iroc, my camaro rs i had got broken into and totally FUBARED so i am going to get insurance money.<br /><br />Here is what I want to do<br />its a 5 spd 1988 btw<br /><br />Cams<br />Gears<br />Ignition<br />100hp Nitrous<br />Exhaust<br /><br />Any idea how much these would cost and the HP gains, and also a good extimate for the 1/4

[Smasher]

It only has one cam, it's not SOHC or DOHC. An '88 should be a roller cam block. You can pick one up for about $200 and get a pretty decent gain out of it.<br /><br />Gears aren't going to be cheap if you get them new. I don't know the costs per se but I know they have to be installed with special tools and set up nearly perfectly or they won't last very long.<br /><br />Exhaust is always a good idea. I have no idea what a catback costs since I'll never need one but I think they're in the neighborhood of $300. You may want to add headers while you're doing exhaust but I hear they're difficult to install on 3rdgens. Not only will exhaust work add horsepower, it will also make your car sound a bit meaner.<br /><br />Nitrous should be one of the last things you do since if you do the other things first then the nitrous will be able to work that much better.

[tj1985_iroc]

Smasher made some good points. To go to a little more detail, you probably want to go with a Comp Cams part number 08-430-8 (from PAW) which goes for $238.95 Matching Roller lifters go for $192.95. For ignition I would go with a MSD 6al HEI kit which goes for $269.95, and a MSD Pro-Billet distributor which is $395.95. As for exhaust, if you are going to keep the cat-back setup, I would probably use either SLP or Edelbrock headers, edelbrock goes for $341.95, and a hooker cat-back setup which is $246.95. Gears aren't really all that bad on price but I would have someone who has installed them before do it. You can get a set of 3.73's for around $193. BTW, if you are going to want to run nitro then depending on how many mile the car has, I would rebuild the lower end of the motor that way I knew that it would hold it ( this is just me though, I don't want a bunch of money in something and just throw it away). Since the car will be TPI I would also recommend getting a TPI airfoil. Hope this helps a little. Oh, probably looking at around 300 hp with this setup.

[L2R]

So thats a 300HP Setup with out the nitrous right?

[Smasher]

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by L2R:<br /><strong>So thats a 300HP Setup with out the nitrous right?</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif"><br /><br />You'll probably have to do some head work(port & polish) to see 300hp with a naturally aspirated 305.

[Newsance]

Some things...<br /><br />1. If you have roller lifters (and none are ticking) you don't need to change them with a new cam. Save $200. Now a flat tappet cam, it is essential to use new lifters for proper break in, but you don't have one.<br /><br />2. If you use a genuine GM gearset, (and your current rearend gears are in spec) you don't need to re-shim it in most cases. GM gears are machined to a good enough tolerance that the line worker can slap any set in, and shim for case irregularities. My GN 3.73 ring and pinion went in for the stock 3.23, and using the factory shims. I paid 60$ for the ring and pinion, 50$ for bearings, crush sleeve, differential rebuild kit, etc, and had a gear swap for under $150.<br /><br />3. Be careful with how wild a cam you go with, as the stock cam is actually pretty decent. I'd reccomend either SLP runners or a aftermarket intake manifold to go with any cam.<br /><br />4. Get headers before a cat back. Your $300 are much better spent there.<br /><br />5. With a manual tranny, make sure you set up your n20 with a window switch. A bottle heater and pressure gauge is a must as well.<br /><br />6. Also with N20, you will want to hook up a fuel pressure gauge for your first run to make sure the fuel pump is up to snuff. When you juice it, watch that gauge. If pressure starts to drop off in the least, stop and replace your fuel pump.<br /><br />Good luck!

[tj1985_iroc]

My 305 dynoed at 339 hp and I didn't port and polish my heads. It has a big-ass cam which helps. 1.94/1.50 heads. Soon I will be putting an Edelbrock Performer RPM Air-Gap manifold on and a 750 carb so I'll have it dynoed again then. At the end I'll probably add a 75 shot to give a little boost. P.S. my motor isn't a roller motor either, It's a 79 305 Block.

[86ZZ4]

339 HP!!!!! nice , so whats it run in the 1/4??

[Smasher]

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by Travis johnson:<br /><strong>My 305 dynoed at 339 hp and I didn't port and polish my heads. It has a big-ass cam which helps. 1.94/1.50 heads. Soon I will be putting an Edelbrock Performer RPM Air-Gap manifold on and a 750 carb so I'll have it dynoed again then. At the end I'll probably add a 75 shot to give a little boost. P.S. my motor isn't a roller motor either, It's a 79 305 Block.</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif"><br /><br />I meant porting of the stock heads. Obviously your heads aren't the stock castings.<br /><br />What heads are you using? What are the cam specs?<br /> <br /> [ 12-31-2001: Message edited by: Smasher ]

[Newsance]

Never mind the fact that running a big cam with TPI won't work because...<br /><br />1. Computer won't like the overlap at all...<br /><br />2. The TPi unit isn't able to breathe where the cam makes it's power.

[SSilverLS1]

My 305 dynoed at 339 hp and I didn't port and polish my heads.

Is that RWHP or FWHP??? That seems EXTREMELY high for a 305 without any extensive head work. I have actually seen pretty extreme heads/cam 305's not do that well on the dyno. Even with a huge cam, I don't see those #'s being possible. Not bashing you, just curious....


Josh