I am in the process of building a 383 LT1 for track days. I am looking for some input on which heads and cam combo to run. My bolt-on mods are as follows:
1) Street legal in CA (need to drive to the track)
2) 10 bolt rear with 3.43 gear and a '93 M6 trans.
3) Intake has been port matched with 58mm BBK TB.
4) Shorty headers, hiflo cats, 3" catback.
5) Moroso CAI.
6) Currently run 275 x 17's NT-01's but will be switching to 315's soon.
7) Water spray on radiator on hot days.
8) Oil cooler and three quart Acusump.
10) All the suspension goodies including a decoupled torque arm.

My objectives are as follows:
1) Needs to be very dependable, that is, it needs to handle ten 20-25 min. sessions per track day in this car.
2) I generally run between 3,000 and 6,000 rpm depending on the track.
3) Looking for a very flat torque curve in the above operating range and a peak HP at 6,500-6,700 rpm.
4) Needs to pass smog with stock heads (which I will switch out when its time).
5) Will run 10.5 to 11.0 compression ratio.

Any advice is very welcome.

 

Maybe a Crane 227 cam w/ good supporting valve train.

 

First off, where can you get an HPDE that has TEN 20 min sessions? Is more than one person gonna drive the car?

Why do you need water spray on the radiator? Are you running a stock rad?

Gonna be hard to get a cam off the shelf to pass a sniffer in a 383 and make some power. You want a cam to kill power off the corner so you are not burning the tires off it on exit.

Get in touch with Bauer racing engines he does alot of rod race stuff.

 

My buddy and I share the car at the track so thus the ten sessions per day. The water spray system works wonders, even on 100+ degree days.

That's an interesting comment about killing power off a corner. I can modulate the throttle and achieve the same effect right? Or am I missing the point of the suggestion?

Should I consider a short duration cam with the ability to swap out to different ratio rockers and stock heads to pass smog? Anyone out there ever tried this? THX for the help.

 

The water injection is a temporary crutch IMHO. If you really need that it's only because your cooling system is inadequate elsewhere.

A larger aftermarket radiator should be high on your list. I've been quite happy with the BeCool, but there are others. Also important is the ducting to it--it needs to be sealed very tightly so every last bit of air that enters the space in front of the radiator must pass through it. Many miss this when they remove their AC condenser, etc, it creates gaps around the radiator greatly reducing airflow through it.

Oil cooler and Acusump are very good ideas. A Canton pan in addition wouldn't be overkill. To that you may want to add a PS cooler and a Turn One pump.

I don't agree about killing power off the corner. You want as much power as you can possibly get everywhere. It's your job as a driver to use as much power as the suspension will allow (so set up the suspension well also).

While the goal, of course, is to maximize the area under the curve keeping the engine spinning where it makes power, depending upon how fast the car is, its gearing, the track, etc, it is quite common to have a particular corner where theoretically you should downshift one more gear for a brief instant but it's sort of a PITA...so it's nice to have a good midrange to pull you out of it if you need to lug it just a tad.

What state are you in? They all have different emissions laws (and they are often different even within states) so passing emissions means different things in different places. If it's a 96+ you may only need a scan, and can pass with as radical a setup as you like. Some places have visual....

But if you need to pass the sniffer, this will influence your cam choice. I wouldn't worry about swapping heads, different rockers, etc. Get the best heads you can afford and be done with it. On a 383 with really good heads, you can make nice power even with an "emissions cam." You will have to accept the fact it won't make as much power, but everything's relative. It might be enough to keep you happy. Any number of well known vendors could set you up.

Of course if you were willing to swap heads to pass emissions, you may consider simply swapping cams instead. Run the nasty one all summer and swap in the stock one after the season is over to pass emissions. It's a lot of work, but no more than swapping heads.

Last but not least, don't spend so much money on the engine you forget about your brakes. Long track days will go through them fast and with more HP you'll find the limits of the stock stuff even more quickly. Ducts are cheap and effective when done well, but bigger more effective brakes can make your day at the track much more enjoyable--and you often save so much in the cost of replacing pads and rotors they actually save you money in the long run.

Hope that helps. Good luck.

 

The reason I said that is more often that not a 383 with too small of heads/cam makes ALOT of torque down low in the rpm range. You want grunt off the corner but not where you are fighting the car constantly for grip off the corner.

On the brakes, I dont know what you have on it now but put the best brakes on the front you can afford. F bodies are heavy and hard on brakes.

 

Listen to Jon A guys. His advice is right on the mark. He is someone who has been there and done that very well.

 

383 will make great torque down low, if you come off the curves at the upper RPM range maybe a high spinning 355 might be better,(all depends on weight, track conditions ect) You will definetly (depending on your state) need a cam with wider lobe separation to help pass emissions, thus needing a cam with quite a bit of duration and moderate lift. Keep the lift comparable with the flow or your heads in order to maintain velocity of outflowing gases..

 

Thanks guys, good advice. I live in CA and its a 1993 Camaro. I have some corvette brakes on the front running Raybestos racing pads. I also have sealed brake ducts which keep temps under control. The stopping power is not an issue at this point but adding 20 mph in certain straights may affect them more. As I mentioned the suspension is pretty well sorted for my taste in fact with the stockish power level I was running, it is difficult to power oversteer outside of 1st gear (the unbalanced engineering decoupled torque arm is an amazing thing). It seems really balanced right now. Lastly, I have pretty much stripped the car of all unnecessary weight including the dash, all ac, all heating related items, replaced battery with a 14# gel cell, and replaced hood with a CF one. I did add a four point roll bar but I think I am still under 3,100 lbs or so.

So based on what Jon A said, I should get an "emissions" cam and the best heads I can afford (which is probably a worked over LT1 setup from AI, or LE). So my only concern with that setup is that better heads would decrease velocity too much at lower rpm's and affect efficiency for a clean burn when under the sniffer test.

Yes this will be a compromise build and not an all out power build so in that sense the challenge is a little different than most of the builds on this site. Please keep the thoughts coming. I am learning...
1)

 

I suggest you talk with Jon A about all of this. He can get you looking in the right direction. Doesn't the car tend to go where you look?

 

If its a 93 car, you can burn a PROM for your sniffer test and one for the track. EFI is a wonderful thing.

Adding 20 mph of speed will make a difference In the brakes. Adding 100rwhp will also tend to upset the car from its current setup.

I am thinking of building a fox coupe thats LS powered for track days and HPDE events, I screwed up and went riding with some buddies who have BMW M3 race cars. What a BLAST! I think I am hooked.

 

Im thinking a lightweight & bulletproof high reving 355 would be a better choice. Wont a 383 add to much low end TQ and add weight to the front of the car and cause more issues and the car to push more in the corners?
I dont road race so Im asking, and not telling you this.

 

There's no weight difference between a 355 and a 383.

 

some good points made in this thread. I would contact LE or AI directly and ask their advise for your specific goals & set-up.

regarding emissions, I run a 383, COMP XFI 466 cam with ported/polished AL heads 2.02/1.60 valves on a '96 OBD2 and pass California smog with flying colors. The tune and good CATS are key though.

 

theres gotta be some difference? Although you could probably offset that with some weight removal.

 

Where would the difference come from? It's the same block/heads/etc.

 

a stroker crank will weigh a little more due to the longer "arm" but you could get an ultra light crank to help with rotating mass.

 

Maybe but you are talking about a couple pounds. Literally a couple if any at all depending on the crank you use.

 

That's such a small nominal amount it's not even worth counting.

 

Cool I always figured it would weigh quite a bit more. Makes me feel better about my 396 build. I just figured its all pretty heavy stock and would gain a bunch, in the rotating assembly.