Driver impressions from those who did some porting please

[billschroeder5842]

Hey all, I like "driving impressions" (not so much of a technical discussions on how our cars respond to some minor work.

I have a '91 that is bone stock except for a Haibeck chip and a MagnaFlow low restriction resonator. I drive the car about 3-4 times a week and would be described as the occasional "spirited" driver. No tracks, no racing but more of a cruiser that will wind it up to 7k rpms on the interstate on-ramp. I take dependability over performance.

What im considering is porting the plenum, adding headers with lower (probably a Corsa) restriction exhaust, new injectors and a decent tune. My guess is about $5800-$6500 all in.

So,
What is the car going to "feel" like? Better/more low end torque? Of is this a midrange or higher RPM combo? Are there any "unforeseen" reliability or maintenance issues? Is it worth the bang for the buck for my driving style of "dependable with an occasional punch?"

I'd appreciate anyone's thoughts from somebody who has "been there and done that..."

[efnfast]

If you like hp, there is no downside.
The only mod I'm on the fence about is installing reground cams. Not sure the driveability was worth the hp gains

[Demps]

I drove a stock car for two years. Saved my money and got a B&B. Thought I was in heaven...until I added headers and Aaron Scott at SGC graciously helped me with a chip. Then I was in heaven. That car dynos at 390 SAE ('95). Stock gears so real power is up top.

Those that know me realize I can't leave well enough alone. I rode in some strokers and was bitten. I even had the privilege of a very good friend allowing me to drive an LPE bodied 415. Well that cost me but well I've gotten off track. Back to what you asked...

In between I traded for a Haibeck 350 (422 rwhp) with 4.10 gears. I think that's about perfect--stock bottom end with gears. I personally think I would like 3.9x gears better but harder to come by. Marc is getting closer to 430 rwhp now with the full deal and stock cams. I personally would stay with stock cams by the way. (Can give reasons if desired).

So, ported top end (plenum & injector housings), tune, headers, good exhaust of choice and you will be in the 390-400 range. That's good! I have a spread of ZR-1s from stock to wild. I would strongly recommend you send the car to Marc or Corey (but I've heard he isn't doing them anymore) and go all inclusive with a full 350 package plus gears. Marc will return the car better. Porting the heads too will get you a car that you now want to drive seven days a week and twice on Sundays.

If you're ever in the Panhandle of Florida we can stroll through stock, bolt ons, porting, porting with cams, 385, & 415.

Ted

[XfireZ51]

IMO, ported top end is how the car should have come from factory. Careful however, because it will lead you to the "dark side". 398rwhp/358rwtq.
Intoxicating.

[Top Toy]

Best bang for your buck, IMO, would be headers, low restriction exhaust and 4.10 gears. Next would be porting the plenum and injector housings. This combo alone will double the width of your grin!

[efnfast]

I did mine piece by piece, I'm sure it cost me way more than the 10 grand Marc charges.
Just a thought.

[RichS]

I bought mine with just a chip and catback. I thought it ran ok but nothing crazy. (I did find I had a bad fuel pressure regulator stuck at 52) I did 4:10's, short shifter, tires, suspension bushings, lowered, rear shocks, brakes ect. It ran better but was still like ehhh? Took my wife for a qick ride and she said "that's it?" (FPR was still at 52) ( We have had a few supercharged C6s one was 550rwhp, one 725rwhp)

Then I pulled the motor, had the heads, intake and inj housings ported, did regrind cams that Lee helped me with, Headers and a different cat back. Now the car feels like I thought it should. Pulls real hard in the upper rpms, but still pulls nice down low. Drives and idles like stock, no drivability issues. Very happy with the car.

[RussMcB]

My rule of thumb is, if you floor it more than once in a while (and for more than a second), and then think, I don't have enough HP, then maybe consider spending money (thousands of dollars).

I have (non ZR-1) friends that never see redline yet think they need to buy go-fast goodies.

[Paul Workman]

Ported my top end and blended the heads (port matching on steriods), Stainless Works headers & X-pipe, Mangnaflow mufflers, 3" exhaust. With Mark's chip and stock cams and TB it put 400 (est) to the ground with zero loss of drivability!

It completely changed the personality of the car - loved it! Loved it so much that the following winter I ported my heads - finishing the porting - except for th TB. Pete phased the cams and Marc did a dyno tune; boosted rwhp to 432. It has practically a stock idle and is a total SLEEPER!

There is NO downside what so ever. As someone said, "They should have come that way!" Can't quite find the words to describe the expression on the face of a local C6 driver after I pulled away from him on the expressway before letting up to let him catch up to cruise along side. Kinda look of puzzled surprise (Heh, heh, heh. (Yeah, that's right, buddy...a "stock" sounding C4 just walked away from ya - like it was nothin'!)

[WARP TEN]

Hi Bill--
I'll chime in here as well. The difference between 375 HP and 510 or so is very impressive. You probably don't need the much greater expense of cams; I certainly was perfectly happy with stock cams, but that is personal choice. With 510 HP the car is quite controllable and easy to drive around town, but a real rush when you get into it. Mine ran 12.4/116 at Beech Bend--not bad for 30 year old technology. If you like the idea of more power as I do (see Mickey Thompson quote below), you will be very happy to have done the mods. One big plus is that the engine can look perfectly stock if you like that, as I did.

But I will also suggest, as have others, that you talk with Marc Haibeck about having him do the work. He and son Bob have done so many of these that he knows all the tricks and also will thoroughly examine the car to see if any other things need doing. (I did 4.10 gears and a Hurst shifter, both of which I recommend).If you like doing these kind of mechanical tasks yourself, fine, but there is a lot involved in getting 500+ HP out of these engines. A lot of little details that need to be gotten right. For a little extra cost premium it was worth it to me to have the world's expert on these engines do mine. If you have not yet, I recommend a read through Marc's Website (www.zr1specialist.com) for a description and cost on the kinds of mods you are thinking of. And a chat with him on the phone might be helpful in your decision making. He always makes himself available to talk to people.

And if you decide to have him do the work, lets us know when you might be coming up and we can have lunch with a few of the FBI guys. Good luck on your decision. Either way you'll be happy with the results.-Bob