My car is a stock 1991 LB9 z28; 2.73 rear. Right now it is very reliable, does not overheat and gets decent gas mileage. The problem is that most any family car out there these days can outrun it; kind of embarrasing when I'm driving a "Z28" and the other guy is driving a Honda Accord!
Anyway, what I would like to to keep my 2.73 rear (good gas mileage for those long road trips), but get the car down into the 13's. I would also like to keep the stock TPI set up, EGR, A/C, etc...
Is it possible for me to simply buy a crate motor, port/polish the factory intake, burn a new PROM, make a few bolt on adjustements, and run 13's? I am looking at this crate motor from Golen :
Chevy 383ci / 405hp TPI Long Block
The 383/405hp TPI is a great high performance replacement engine for your tuned-port injection street rod. With 492 lb/ft at 3500 rpm, 405 horsepower at 5000 rpm, and a good idle, this engine works well for both street and strip use. Requires a high performance chip for the ECM which is available from Golen Engine Service.
Peak Horsepower: 405 bhp @ 5800 rpm
Peak Torque: 450lb/ft @ 3500 rpm
Operating Range: 1800 - 5800 rpm
Compression Ratio: 10.5:1
Required Fuel: 91+ Octane Pump Gasoline
Base Price: $5,699.00

Cam:


















Manufacturer:
Comp Cams

Type:
Hydraulic Roller

Operating Range:
1800-5800 RPM

Idle Quality:
Good

Duration:
Intake: 224˚@ .050”
Exhaust: 230˚@ .050”

Lift:
Intake: .536”
Exhaust: .544”

Lobe Separation:
112˚
Heads:
Type:
Partriot Performance 185cc Aluminum

Flow:
260cfm @ 550˚ life on intake

Spark Plug Type:
Angle

Combustion Chamber:
68cc

Intake Runner:
185 cc

Intake Valves:
Ferrea Stainless Steel 2.02”

Exhaust Valves:
Ferrea Stainless Steel 1.60”
Optional Parts

4340 forged steel crank $300
4340 forged steel H-beam rods $300
Canton 6-quart road race or drag race oil pan $300
SFI approved flex plate $120 (auto trans)
McLeod standard flywheel 153 tooth $450
Fel Pro intake gasket $30
Fel Pro moulded rubber valve cover gaskets $55
ATI Super Damper $375

 

Also, I should add that I have looked through the TPIi forum and have seen alot of info that says the stock TPI will support this and alot that says it wont. Now I am confused. I know the stock TPI is not good for high RPM. I dont mind having a chip burned, but at this point I don't know how to do it myself. If I need to I would also swap for 3.23 or maybe 3.42 gears. I am looking for decent performance, but with good reliability. Also, I'm open to suggestions, as I have not made the purchase yet. Thanks!

 

Your idea is fine except for a couple of spots.
The 2.73's will be fine if you get the right converter. A really good locking converter with a rating around 2400-2600 RPM will be great. I like the Vigilante (Precision) brand.

The camshaft supplied with the engine is too much for a highway geared TPI even of 383 cubes. You want something with about 10* less intake duration. It will keep your power curve exactly where you want it lower in the RPM range around the shift recovery, and will also satisfy your fuel mileage requirement. The best lift numbers for a cam will depend on your choice of cylinder heads and what their flow curve looks like.

The heads listed would work fine and you'd want to keep valve lift in the 0.550" - 0.600" range. You may consider higher ratio rockers to accomplish this with a milder camshaft choice. If you want to run on 87 octane then you want to keep static compression down to around 10.5:1 with aluminum heads.

You definately don't need all those forged parts to run 12's or 13's. It shouldn't hurt anything, but it's not a neccessary expense.

The 6" rods and floating pins are also not neccessary for your performance goal.

A factory chevy oilpan with a windage screen will do the job fine.

I do like your overall choice of combination for the whole car approach. I have no doubt that you'll get more than you're expecting once the car is properly tuned.

 

Thanks for the info. I agree, a converter will be needed. Will that hurt the fuel mileage much?
There is one other crate motor that is about $600 cheaper that I also like; the GM ZZ383 (p/n 12498772).
I realize I would likely not get the advertised power and torque with either one if I use a stock TPI system, but... would it run well? and any guess as to how much hp I'd lose?

 

The fuel mileage should be fine with a good tune.
As for converter, I specified a lock-up converter so it shouldn't harm you mileage numbers.

You can't say how much you'd lose, because the question becomes "compared to what?"
I think you will run very well.
With a 700R4 and 2.73 gears your engine combo will work very well with the TPI. Your power at shift recovery RPM will be very strong so you should E.T. much better than your maximum horsepower number would predict.

So what if you lose 100 horsepower because of your camshaft & induction choice? The same engine with 100 more horsepower might not run any quicker in your car given the same transmission and rear gearing since its power would be shifted higher in the RPM range.

You can improve your power with a larger TPI base and larger runners while still preserving your power band and fuel mileage.

 

youd lose 100hp with TPI?? on a beefy engine like that...holy crapp!

 

Pretty cheesy heads for that kind of money.Should have AFR heads.

 

Quite honestly, I think you're trying to wear too many hats. If you got 100 car guys in a room and asked them to build a reliable, economical performance machine, not one will recommend a 383 TPI in a thirdgen.

I'd say either buy another car as a daily driver and keep/mod your car, or buy a fourth gen with an LS1.

...don't get me wrong, I LOVE the idea of a 383 TPI, but that's gonna be a project, not a driver. I'm sorry if anyone disagrees, but it's just not gonna be as simple as pulling out your wallet and being done with it. It's always going to require attention. Not saying problems, just attention. It's never gonna be as reliable as what you have. ...and even if the motor is flawless, you'll end up breakin' other parts. The tranny for example. ...and in a few years, you'll be drivin' that Honda everyday to work and the Z will just be a weekend car anyway, .....-like most of us. (maybe not a Honda, but you get the idea).

 

I just finished talking to Chad Golen (Golen's Engines). He said that I could take this crate motor and use my stock TPI system on it. However, he recommended new runners (SLP, Edelbrock, etc...), a new throttle body, lower intake, and a chip. I asked if it would be as dependable as my GM motor, he said yes. I told him my car does not overheat now, will it with this new motor? he said it should not. As far as fuel economy, he guessed between 14 and 16 (which would be reasonable for me).
This all sounds too easy....what am I missing?
Abubaca.... I hear you on the 383 not being as reliable and you are right..I am looking for reliable, fast, and 'somewhat' economical (at least as economical as I get get in a 400hp car).....besides a 4th gen (there is just something about the 3rd gen I like a whole lot better) any other suggestions?

 

this is just my opinion, so take it for what it is worth...

you sound like you love your car as is; doesn't overheat, good gas milage, reliable, etc... but you just want a little more performance so every econo-box car on the highway doesn't blow you away.

your considering spending a lot of money on a new "400 hp" crate motor yet you want it to be economical at the same time... or as economical as a 400hp could be.

why not just swap your rear end gears?? Its the quickest and cheapest bang for the buck right off the hop. You didn't specify if you have a 5 speed or an auto, but I'd bet you've got an automatic. Swap the 2:73's for 3:73's and you'll be surprised at how much harder it pulls, yet it won't be that bad for gas milage. Sure you'll be on the go pedal more often because you get addicted to the torque, but you'd do the same with a 400hp motor.. once that wears off you can get a true reading of your new gas milage.

It'll be a lot cheaper (like 10x) to do the gear swap then an engine swap, all things considered (keeping the 2:73 gearing), your gas milage will roughly be the same whichever path you choose. Oh and if you've got a 5 speed, go with 3:45 gearing.

 

i sympathize with your goal. right now i have an 86 iroc with an lb9. same induction setup and everything. and my plans are the same aswell. im looking to build myself a 383 tpi. i plan on making it reliable yet still somewhat fuel efficient. although i dont have as much cash as your planning on your engine, i plan on building mine from scratch. and im going with cast iron as opposed to aluminum heads.

you can make your 383 reliable, you just gotta not cut corners. get your car tuned correctly, and dont skimp out on your transmission and driveline, or your suspension. think about how much torque your gonna be putting, its about twice as much as before so your tranny, u joints, rear end gears, bearings, and suspension are gonna be working double time.

 

Dont forget the subframe connectors and headers and full exhaust upgrade with that as well.

 

I know fast, economical, and reliable usually all don't go together....I think a gear change to 3.42 might not be a bad idea either.
Has anyone on this site been successful at building a 13 second car that is still streetable, reliable, and is not overly complicated with aftermarket parts?

 

Uhhh no.... If you use a stock TPI setup, and dont tune it, then perhaps. But no, swapping a carb to a TPI will not lose 100 horsepower, no way. What happens with TPI is you shift the power band lower. So you gain lots of torque from idle to 4000 rpms and then the horsepower falls off after 5000 rpms. Where with a carb it would have no torque until after 4000 rpms and then fall off after 5500-6000 rpms.

I posted a great 13 second streetable combo in your other thread.

 

thanks, I'll check it out. I am really trying to make this work. I love my 3rd gen, but stock it is too sloooowww. It is a great road trip car and thats why I'm looking for the reliability, streetability, and the ability to buy reapir parts at the dealer or auto parts store.

 

yep Brisk,I agree 100%!
leave the motor alone and stuff some gears in the rear.

91zeee,don't know how many miles are on your car but,might also be worth throwing a new set of injectors on the lb9.
If your car has the stock multec inj.,it may be worth while to replace them?