My 89 L98 Iroc doesn't hold alot of oil pressure as is so I'm just going to pull it out and do a rebuild. This car will be my DD so I don't want anything to radical but I do want to bump it up quite a bit. I'm still running a stock 700R4 and I'll be running a 3.42 gear. I don't want to sink a fortune in it but I do want to put a cam in it while its out to save work later. For the time being I'll be running a stock TPI and what would be a factory casting head I could go to that would give me some power if there are any. A friend of mine swares by Vortec heads. For the cam I do want a nice chop but still be stock converter friendly and not result in a slower car with the TPI. Remember daily driver. The car all ready has the baffles removed, KandNs, maf descreened, Hedman shortys, no cat, flowmaster muffler. Thanks

 

Vortecs are good, but you would have to change the lower manifold to fit. also, Vortecs are D-ports (have D shaped exhaust ports) [at least the Fast Burn Vortecs on my 89 Formula 350 are D-ports] meaning you would probably have to run a different header - and to make matters worse, they only make square port shorties for our cars. i ended up using a Dyno Don header/Y-pipe combo.

anyway, if the motor is out, now is definitely the time to replace the heads. outside of cast iron Vortecs, i would go aluminum. alot of people here like the AFR 195's. if you want to go milder, and spend alot less money, aluminum L98 Corvette heads (or equivelent) run pretty good.

i went with a ZZ4 cam on mine. it has a smooth idle, would probably be a good match for aluminum L98 heads, and you probably dont need much more than that on a stock TPI induction. besides, a lopey cam on a third gen seems a little outta place to me, especially if its a daily driver.

i would do a TransGo shift kit - its one of my favorite mods {more reliable kick-down and firmer shifts}

also, i am one of those people who swear by throttle body Air Foils. not saying that they net a bunch of power, but they do improve throttle response.

one last thing - since motors already off, if you can swing just a couple more hundred dollars, go ahead and get some Roller Rocker Arms and make it a full roller valve train.

you going .30 over?

 

Regular Vortecs are not D-ports. They're just vanilla truck heads, really. Any exhaust manifold will work.

The Vortec TPI base is restrictive and expensive. The heads make up for it, but if you just want something reliable for a daily driver with a little punch, I'd just stay with the 083 heads you have. They're good. Probably the best factory iron gen I sbc head after the Vortecs.

The problem is the TPI and a choppy idle arent really going to get along. It takes a fairly large cam to get a choppy idle, and even my cam sounds lazy in my car, and the power band goes way beyond what a TPI can handle.

Unless you want to start porting your intake base and buying some siamesed runners and porting those while you're at it and retuning everything I would probably just leave it alone. The costs escalate SO quickly when you start trying to do performance stuff, and I think in your case something reliable is more important than something quick, and the factory TPI 350's arent really slow to begin with.

I would put maybe a slightly larger cam in it, but you may have the 10066049 which is 207/213 cam... which seems to be of a reasonable size considering its stock.

In fact... this is what I think I would do. Changing the duration too much will send your powerband too far past where the TPI works. So get a roller cam that has nearly the same duration, but has modern ramp rates. The Comp 08-302-8 would be a slight improvement on duration, and a big improvement on lift, which should translate into a lot more torque. I'd go bigger but you start running into tune issues with the stock tune. You will need to change the valve springs and have the heads set up for the cam, which should be easy for a shop to do while you have the motor apart.

But I think trying to make a daily driver a street demon is going to get you in trouble in this case.

 

I had actually planned for a HSR just not at the same time as the engine rebuild because the motor will be done in the next week or so. I may just leave everything stock and mod everything at once later on. That way I can get the tune in one round. The reason I don't want to mess with the converter is because I'm not sure what kind of life or mileage the transmission has. The car has 107k but it seems to have been well cared for but you never know. I'd hate to put in a new converter and then the tranny give it up and ruin it. And while everythings apart would it be worth porting the stock plenum and runners for a more or less stock motor?

 

if u wanted to go with vortec heads i would also get KEN's vortec FIRST tpi setup at firstfuelinjections.com..... looks just like a stock tpi but its blown up and at alot of performance that slp, edelbrock and accel cant touch unless you start really grinding and welding those parts.... just something else to consider on the table... i have a first and i love it....