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 2 crate motors; one from Golen and one from GM:

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

GM:

Top > Small Blocks > ZZ383 Crate Engine 425HP 12498772ZZ383 Crate Engine 425HP 12498772



SKU: 12498772
RETAIL: $7,357.14
YOUR PRICE: </B>$5,228.00

ZZ383 Crate Engine 425HP 12498772 Description With GM's legendary Fast Burn cylinder heads and 383 cubic inches, the ZZ383/425 delivers incredible torque with smooth, linear delivery.

If your're looking for a small-block package that delivers big-block power, then you've found it.
425 horsepower at in incredibly low 5400 RPM, and 460 ft.lbs of torque at 4500 RPM make this the ideal hot street engine.

The excellent air handling and combustion characteristics of the Fast Burn cylinder heads combined with the ZZ383/425's 3.800" stroke, make this engine the benchmark against which all other 383 inch small-blocks should be measured. And its tough, too.

The 4340 nitrided and induction hardened crank and unique forged PM rods see to that.
The 9.6 to 1 compression ratio ensures that the ZZ383/425 is 92 octane pump gas friendly.

The ZZ383/425 gets a stout .509/.528 lift steel camshaft with 222/230 duration at .050 lift. Hydraulic roller lifters and GM's time tested 1.5 to 1 roller rocker arms round ou the valve train.
And, of course, it has the Fast Burn head's lightweight stainless steel valves and retainers for reliable performance at extended RPM.

GM's testing was completed using a GM single plane intake, P/N 12496822 and a 750 CFM Demon carburetor with mechanical secondaries.
Test header specs are: 1 3/4" primairies,33 inches long with a 4-inch collectors.

GM dual plane intake P/N 12366573 may be used for hood clearance on the ZZ383/425, but it results in a decrease in peak horsepower of approximately 15-20 horsepower.

 

you will definitely run out of steam above 4000 rpms with that 383 and stock TPI.
the stock TPI was good for about 5 liters and thats about it.

from what you have said, there is no reason to get a new crate motor.
13's are not hard to get with a cam and exhaust.
you could get the ported runners and that would help you out a lot.

maybe someone who knows more can shed some more light, but in my opinion, a 383 TPI will be great below 3000 rpms, but after that, you wont be going anywhere.

 

Both of those engines will require a custom computer chip, just remember that.

Also, both of them will hate having to lug around with your 2.73 gears. Those gears work with stock engines but not with performance engines. The minimum you should have is 3.23 gears, and preferably 3.42's.

Also, you dont need a 383 engine to run 13's. In fact, if I had a 383 engine that only ran 13's I'd call it a pig and put it out of its misery. A low 13's combo can be accomplished with something as simple as a ZZ4 engine, but I'd use different heads with it.

You need to and read the TPI forum and read about other people's TPI combos and see what they have done. That'll give you a huge education and help you plan out your mods more effectively.

 

thanks for the info. Yes, the TPI forum is great. It seems that there is a lot of complicated wiring, cam changes, head and intake work, etc.... going on. I am looking to see if I can take the simple route and get a 13 second car without going to a whole bunch of custom work. Looking at what you guys have to say here it looks like I can, might not need the 383. Now...... I just need to see if I can find someone on here who has done this.......any suggestions??

 

Sounds like your looking for something more or less plug-n-play. Instead of choking an unnecessarily large 383 with the stock TPI system, just get a GM ramjet fuel injected 350cu in. small block. 350hp/400lb-ft, complete with wiring harness and computer.

https://store.gmperformanceparts.com...-12499120--%3E

-Zander

 

yes, not a bad idea, but I am also trying to keep the car stock appearing and also keep it so it will pass an emmission test. I like the RAMJET though.

 

I ould recommend a mild 350 with a procharger or similar supercharger setup. It's not stock looking, but it will let you keep the TPI almost untouched (You will need bigger injectors and some other mods) You will still have decent fuel mileage and plenty of horsepower when you want it.
You will spend a lot less money overall...

 

350 roller cam engine block, crank, and pistons
Comp XFI268HR-113 camshaft
Dyno Don 1 3/4" headers, high flow cats, 3" exhaust
Trick Flow heads
Edelbrock TPI intake
SLP or AS&M siamesed runners
everything port-matched to each other
2400 or 2800 stall converter for beefed up 700R4

plus the standard suspension mods and drag radials and you'll have a low 13 second car that makes about 300 horsepower or more to the wheels.

 

I like it....350 is probably more durable anyway. Do you have or know somone who already has tried this combo?

 

That is a pretty common combo. You will find them like that all over these boards. It isnt cheap, but isnt too expensive, either. It is also very durable and dependable. (Except for the drag radials. I wouldnt recommend them for a daily driver that sees a lot of miles.)

 

Yes, Allen here in SoCal has an '89 GTA. That was one of his previous engine combos. It made 330 RWHP with a 700R4 trans, 2400 stall converter, 3.70 ratio 9-bolt rear end, and went 12.70 @ 106 MPH at Fontana. Dont forget the custom chip tuning that will be required for that camshaft.

When I said drag radials, I meant for the track only, not for the street. I change tires when I get to the race track.