i have a simple questions hopfully to get a simple answer. I was seriously thinking about a whole new build up on my 89 Iroc-z L98 motor. simple bolt on mods to allow better performance to get this engine breathing way better than stock. this is what im working with. Edelbrock centerbolt heads base intake and runners, as well as TES headers. Now i need a slightly better cam that allows normal vacum like a 112 lope. i need some major help on cam choice that allows a very nice tone in the exhaust without causing my self to much trouble, slightly bigger than stock is perfect, and the use of 1.5 rollor rockers are fine, the heads are limited to .575 lift, and i seriously doubt ill need that much unless the heads and base as well as runners will allow it. i plan on using Moats Ostrich system with tuner cat RT. I have learned from others and from the fourms that this system is the best for what im looking for. hopfully i can pull out at least 325rwhp, knowing that the tpi system is mainly used as a torque monster 325hp is all i need considering i might see close to the 400 range in torque. a T56 transmission is soon to be installed into the car in mid june to early july as well as either 355 or 370 gears into the rear of the 9 bolt rear end (if possible close to 355 for milage reasons). i want this car to be a really nice Iroc-z and i love the design of the runners from edelbrock. So my basic question is, can you point me to a cam that would best suit this package and give the street monster im looking for. also will i need to get bigger injectors and/or TB if so what size of the two, thank you for your help this is defintly the combo im going with.



John

 

Go with the bigger gears for sure. I am running 3.73's in my 5 speed car. They rock . Also when in top gear the revs are nice and low. Seeing how you are putting in a 6 speed , I'd even consider 4.10's ...but they wouldn't be well matched for the 1/4 mile ( TPI intake) I say I would go for at least a comp cams 268 ...or bigger ( you have the heads so go for it ) . 24 lb injectors ..and a stock TB will do you just fune ( maybe step up to a 52 mm TB ...but myself would keep the stock TB for throttle responce)

 

outstanding, thank you for the advice

 

Well, motive gear has great gears, in 3.70:1's. The gears are phoenix and sun cut, so quieter and stronger than others. Also, why stick with the TPI intake, it's only like $650 for a HSR and fuel line and all the adapters you need. I have already bought one, and I'm planning the swap. If you go to my site at www.cardomain.com/ride/471099 You can see what I did with the TPI in my '87 IROC-Z L98 motor, it's on page 8, on page 3 is my plans for my formula, and on page 1 is my formula, and I have picks of when I ported the stock heads. But they had core shift, so going with 2.02's was a bad idea in my case.

I also have pics of all the work I did to my HSR intake, that thing rocks, it's good, even if you have manifolds, for about 35 hp over stock, more with headers, and it will clear the stock camaro hood.

On page three, read through it, and see what my plans are. And on page 8, you can read about everything I did with my IROC-Z.

But I hope you didn't buy the edelbrock big mouth base and high flow runners. Someone else makes a version of the TPI intake made for a 350, bigger runners, base, and doesn't make peak hp until 5500. But it would be easier on the pocket book, and you can take the HSR to way more hp anyway, with decent torque still.

That 9-bolt rear end is great, many don't believe in it, but it has a closer spacing for the ring and pinion; the 10-bolt has a wider spacing, and as the rear end flexes under torque, it makes the spacing even larger, and breaks the gears.

The 10-bolts that are older, say from my dad's '68 GTO, it's on page 11, it's a stronger unit, than the units used in the 82-02 f-bodies.

 

Your are going to need some good flowing heads to get 325RWHP. It is easier to do with the M6 though than the 700R4. I don't know what your Edelbrock heads flow.

 

Well with a HSR, and headers; you'll add about 100hp.

35 hp proven on the dyno, with one unported

25 hp with shorties and exhaust.

Spend the money and get the Comp Cams, Steel Pro Magnums, 1.6 ratio, they drop oil temps by 35*'s as proven by John Lingenfelter, get his book. And you'll add about 12 hp.

Then if you do a 160* thermo, that's 3 hp, a tb bypass, that's 3 hp gain but with a HSR, you don't need to do that, because you shouldn't have it on that manifold anyway.

Don't do a diff throttle body, the stocker is good enough for the 502 with fuel injection. I wouldn't get a bigger TB unless your running a 406 CI'er and running to 6500K, with a lot of improvements to make up the need for one. But the TPIS air foil can give you another 36 cfm of airflow, TPIS says is worth 11.8 hp. TPIS is the first make of an AIRFOIL too.

Also having a Adjustable Pressure Regulator, works great, they are definitelly worth the fifty bucks, get a gauge also. Higher pressure is worth about 10 hp, and 9 lb ft of torque. At the track if your having some traction trouble, off the line, you can turn the pressure up a little higher, and the motor will bog, just until your off the line.

Then if you do some sort of cold air induction, with K&n's, cut out the baffles from the factory, dual filter lid, where the dual snorkel goes too. Then where the MAF attaches to the lid, that spot that is a restriction to the air flow, hurts the efficiency. Also remove the MAF's screens, and also you could remove the FINS, but not if your going to drive the car a lot, but I did, for my formula. I did a lot of these mods, if you go to my page 8 on my site, you can learn that it all worked great.

Then you'll be all good. I have a lot of experience with these TPI's so, let me know if you have questions.