italiano67

iTrader: (1)

Hi there, I have an 89 Iroc with the 5.7. I bought the car with a new Spartan reman engine that 15 K miles later has developed a lower end knock. Warranty time has expired and not looking to buy another one of those even though the price is $1350 for a reman. My parts currently are as follows: Rebuilt and slightly bigger throttle body, adjustable fuel regulator, PCMforless chip, reman ECU, low temp thermostat, new stock dizzy, Hedman long tube headers, underdrive pulleys, K and n filters, smog pump delete, newstock Multitec injectors, stock 700r4 with shift kit, 3.70 gears. I am under no illusions of building a race motor but would like to add 30 more horse or so with full durability etc. I don't have a clue what kind of mishmash parts are in this cheap crate motor so my plan is to have a machine dissassemble it and check it out, probably throw a rebuild kit in and balance the engine. Possibly a ZZ4 cam along with the springs etc and screw in head studs. Would like to keep the machine shop bill at or under two grand. Looking for input on reasonable options with the engine being taken apart anyway. I don't have a lot of wrenching knowledge so once its together I wont be messing with it to add things later.

JoeMonte

Get yourself a good comp camshaft, not the chinese knock off brands, and invest in really good gaskets, its worth it. Maybe an intake manifold or if you really want good power port and polish the heads and you'll have a mean cheap setup. Don't expect to be super cheap, you can try and build a motor for 4-500 dollars but you're gonna be sacrificing quality. Use all new wear parts, bearings, timing chain, gaskets, oil pump, etc. If you spend 1000-1500 you can have anywhere from a 350-400hp motor and it should go for a long time. Best of luck.

redneckjoe

i would suggest asking around in your local area for the best, experienced, reliable machine shop with a good reputation. then pay them a visit. explain what your expectations are, get an estimate, see what the time frame looks like, etc. unfortunatly there are some shops with bad reputations that do shabby work out there. maybe attend a few car shows or ask some hotrodders , racers, who they recommend? sometimes you can find deals on motors they've already built and the customer didnt pay the bill.

sofakingdom

iTrader: (1)

Heads are key. Get the casting #s of what you have. I'd almost be willing to bet money that they're either 70s smoggers like 882 or TBI swirlies such as 193. Garbage in either case.

When you get around to the cam, pick one optimized for TPI. You've already got a serious mismatch going on with those gears. TPI will prevent any motor you put it on from producing meaningful power at the RPM range those gears force it into, up beyond the "tuned" range that the runners enforce. The ZZ4 cam in particular is well and widely known as not a good choice. The Comp "502" grind https://www.summitracing.com/parts/cca-08-502-8 is probably just about perfect.

Make power with a good head choice. That's the best place to spend your money. Get good quality aftermarket ones with 64-67cc chambers if iron, and 58 or so if aluminum. Use flat-top pistons without the usual added "rebuilder" .020" of deck clearance, and build it to zero deck clearance (will probably require decking the block) Beyond that, don't get all wound up in expensive bottom end work; TPI will protect it from ever seeing any significant stress. Stock crank & rods, in good condition, are fine.

This is a REAL motor, not some Honduh, where each aftermarket accessory you buy "adds" xx HP. You know; the air cleaner pipe "adds" 25 HP, the fart can "adds" 15 more, the wing "adds" 30, and so on, until the n00b thinks he's got 350 HP coming out of that weenie 90 HP thing or whatever it is that they come with, and it still runs the same 16 seconds it did when his big sister gave it to him after she graduated from college and got a job.

Realistically, out of all the things you listed, the only one that makes a significant difference to the power output, is the headers. With those and a good exhaust, plus a good set of heads and the cam and short block specs I gave you, it should be able to make around 290 - 300 HP.

Orr89RocZ

iTrader: (20)

Just tuned a fresh rebuil L98 today. Hedman longtubes dual 2.25" and stock motor everywhere else except i believe that comp 502 cam. 218/224 i think are the specs in this one. Stock automatic

It made 226 whp and 309 wtq. Not bad but not fantastic either. But a good fun sounding combo on the street

sofakingdom

iTrader: (1)

That's pretty believable: 275 - 280 HP and 380ish ft-lbs at the crank. A reasonable result for a well matched TPI motor. Not going to run with the Pro Stocks, but you'll have a good time on the street, mostly.

Orr89RocZ

iTrader: (20)

My full bolt on stealth ram L98 with 1.6 rockers on stock cam made 254/315 lol. I think intakes are more important on stock heads. Kinda need with a cam imo

sofakingdom

iTrader: (1)

Right: that's a Stealth Ram though, not TPI. As long as TPI is used, there's a built in brick wall limit, the only ways around it is nitrous or forced induction.

MSgt Luttrell

All good advice, power increases are made with heads, cam and intake choices and yes, the TPI system is a road block; it was designed to make good low end torque back when 195 HP and 250 or so ft lbs of torque was competitive on the street.