tlxxtl

OK, I purchased my 1989 c4 less than a month ago, today I took it to a friend to discuss several issues. (I have to go back to get them looked at) He is a engine builder for Racing Teams (certified) yes those teams, he offered to boost my car to 600+ hp I am thinking it over... this car was supposed to be a weekend cruiser not a weekend bruiser. Now i do agree that some tuning is needed as take off id great but after that it lacks some power... What should I do? Help!

92ragtop

Go for a power boost, but 600HP = $$$ now and in future maintenance. Maybe a more modest 300-350HP is plenty for a cruiser? Lower $ and better reliability.

gerardvg

600 hp is nice but as you have already noted they have some drivabillity issues with hot cam and high rpm, fit some long tube headers an adjustable fuel pressure regulator.
Set the fuel pressure to 48-52 psi and enjoy the ride.
That will knock a second of your quarter mile time and start easy and be well behaved in heavy traffic.

If you want more hp a TPIS cam for TPI engines works a treat, some aftermarket heads will put you into 12 sec quarters.

cudamax

If ya got the dough Do it Let-em build you a nice Killer mouse motor

DanielRicany

Take off is great and lacks after that is because of your TPI intake. It chokes the engine above 5500 RPMs, and the torque falls off I believe at 4800.

cadmaniac

It's easy to get caught up in the 600hp small block game. Kinda like a high maintenance woman, they are intriguing to get, but hard to live with. I actually just sold a 540hp small block 400 to put in a nice 350 with a LT4 cam and heads, and headers and upgraded intake.

I can get decent performance and good gas mileage, and not wrestle with brakes, and actually enjoy driving the car with a/c.

Of course I'm getting older now and appreciate the refined aspects of a car.

Good luck

Race Prepared

Determine how you will use the car most of the time, develop a plan to improve the cars engine performance, brakes, & suspension, and set a budget.

tlxxtl

I am 50 and all the things that you have mentioned is what I have on my mind. Good advice. We'll I am seeing him on Monday or Tuesday and we will work this out. I have to remember my wife also drives this car.

tlxxtl

What hp would my reliable limit?

65Z01

Years ago TPIS did a build up on a 90 or 91 Vette with exhaust, intake, cam and heads to get around 350-370chp and commented that this is the Vette that GM should have built. I would also suggest ignition improvement like a HyperTech coil/cap/rotor and low resistance wires.

If it has an A4 I would also suggest a 2,000rpm TC with TransGo shift kit. And have the WOT shift points raised to 5,800-6,000rpm. But keep the 2.59 rear for cruzin comfort.

cadmaniac

Actually, having to do it over again, I probably would start with the Lt1 platform. They have decent all around performance, except for the opti-spark. It's going to take a lot of work and money to make an L98 a quick car, and a few of grand at least.

Lots of similar questions if you search.

Here's a rundown:
Phase 1
Corsa Exhaust $1100
TPIS or Hedmen Headers $400 - 800
High Flow Intake $400
High Flow runners $300
Tune $200-500


Phase 2
Stall converter $350-600
3:73 Gears $400-1500
Heads $750 - 1500
Cam $150 - 350
Super - Ram / Mini-ram intake $1000 - 1500
Re-tune the car

If you think a carb conversion will be cheaper been there done that. The exhaust will stink, the a/c wont work right, and the car will never behave like it was meant to. This all varies like opinions, of course. If you want the car to work like a 68 Nova, I would buy one of those.

But if you like the car, thats the deal. The prices I mentioned vary greatly depending on who does the work, and every change will affect the behavior, driveability, & fuel economy.

Choose wisely grasshopper......

tlxxtl

Thanks for the good advice... Exhaust done, headers done, cam done all by previous owner. I think they also changed heads as the spark plugs are from a different year.(I think LT1)

tlxxtl

Got my car back today... Here is an update.. I listened to you guys and went mild instead of wild,
I also found out that the timing was off by 6 degrees, throttle body was leaking air and the EGR, MAF, and a couple other things were blocked or coated with carbon. My drivers side rear caliper was sticking and one side of the exhaust was loose. Whew!

Now I can say that I have a Corvette. And it feels like it should in the seat of your pants.