inde-fab

Im dropping the motor into an 81 Camino thats being built for shortcourse off-road and desert racing. Im not really looking for huge numbers, just reliability, solid midrange power, and tuning simplicity.

Shooting for the 400-420hp range between around 3 - 6k rpm
the car will weigh roughly 4500lb loaded

My questions are-
1 - What cam/durations would be ideal for this setup.
2 - Victor Jr or Sr?
3 - I will probobly end up using the Edelbrock for offroad vehicles, "lo rider" is the series I think, what tuining can I expect to do initially.
4 - What style headers are best for this power range, any exhaust suggestions are welcome too
5 - What would be the ideal components for a VERY reliable fuel system

I think that's the main concerns right now. I'm a couple weeks from buying all the engine parts so I'm trying to really get a better grasp on this setup. I have been using V6 Toyota motors in my trucks for years, but just recently decided to build this Camino chassis for the unlimited classes.

Thanks for all your input so far, you guys are very helpful here. Cheers.

speedtigger

iTrader: (16)

You mentioned reliability as your primary concern and an RPM range of 3,000-6,000. I would also assume that acceleration out of corners and good performance when RPMs are not ideal is essential?

If this is the case, I would suggest you use the Performer RPM dual plane intake. All of the tests that I have seen show a much better torque at low RPM and midrange with only a small sacrifice in the 5,000-6,000 RPM range. It might also be a little easier to tune.

As for the camshaft, I would say something line the Comp Cams XR273. It has a duration around 220 degrees @ .050" and a modest lift of about .530". I think this cam will give you the RPM range you want with good reliability that is easy on the valve train. Also, for your type of racing where endurance is essential, get the very best valve springs you can find.

Pop N Wood

iTrader: (1)

You didn't mention what motor and heads you are running. Everything you are talking about, cam in particular, depends on the type of heads.

I am not a big advocate of dual plane manifolds on LS motors. You are sort of giving up the big advantage of a carb's open plenum design compared to the EFI's long intake runners. If you have L92 heads than I don't believe they even make a dual plane for those. I could be wrong there.

Your power goals say 3 to 6k RPM. Being an off road vehicle means you probably don't mind keeping the revs up. A futher reason to go with at least a vic jr. For a bigger cam you may want the vic sr.

You didn't mention whether the HP goals were at the crank or the wheels. A dead stock carb'd LS2 exceeds that HP at the crank. To get that at the wheels will require something a little larger than the stock cam. I will tell you an LS2 with a GMPP intake, stock LS2 cam and 243 heads (same as the LS6 cam and heads) flat purs from 1500 RPM and up. You can save some money sticking with stock cams.

I'm not familiar with that carb. Tuning a Holley on an LS motor is not hard, but it is a little different from a first gen SBC. It takes some experimenting to get the off idle tuning just right. > 3k RPM was easy to get right. Even I pretty much nailed that with nothing more than the right main jets.

Reliable fuel system? Not sure exactly what to tell you except use good filters both before and after the pump. My first pump, a georotor design, ate itself on some tank debris. But that was my fault for not cleaning the tank. Rotory vane pumps are suppose to be more tolerant of dirt than the georotor designs. I'm now running an $85 summit brand pump with maybe $200 in filters and other than being noisey everything is working without fault.

allblowdup

I would go with the gmpp single plane intake. If you go with factory ls3 heads and the lsa cam or ct525 or ls515/376 being 226/236 .525/.525 110l/c it has been designed by GM to reach goals plus has been tested for durabilty. Those parts are cheap. Go with approx 750 cfm carb and drive the crap out of it.

inde-fab

sorry I spaced on the motor info. I was told its a 1999 LS1. all stock, I guess I should decode the numbers to be positive before I order anything though.

I doubt If I will be putting 400 hp to the ground without making over 600 at the flywheel. I have been told the 900hp trophy trucks I'm going to be competing with only get about 500-550 to the ground! This first setup is just going to get me thru the first year of testing and some short races. Once I have a good idea of what she does I will likely build another engine for shortcourse that pulls a bit more in the upper rpms

Great info. I like hearing whats worked for different setups.

I will be running it hard as hell on the shortcourse, but in the desert I'm gonna run lower rpms hoping the LS efficiency will help the pit strategy so I don't have to carry 80 damn gallons of gas! I may have to get the efi setup dialed for that reason later but we'll just have to see how she goes.

The edelbrock lo-rider carbs have a tube that runs between the float bowls I believe, connecting them and eliminating the draining of the bowls in extreme off-camber and uphill/downhill situations.

I imagine I could retrofit most carbs to get the same effect, then I guess It would be a Holley or Proform. Around 700cfm seems to be about right, maybe 750.

Z284thgen

iTrader: (46)

Dont for get rod bolts for a piece of mind on them stock rods

3pedals

iTrader: (3)

Well, now that you have lay'd out the engine your starting with and your performance goals long term.... dont buy parts twice!
Start with a vic jr intake, a msd 6010 ignition, get At LEAST 750cfm carb.
My opinion on a cam is run the stock cam till you get ready to make more power, then call a Valve train specialist to pick cam specs, valve springs, and push rods to get you the most power WITH reliability for your combo's intended usage. I recommend Bret Bauer Racing for valve train design.
The stock cam will run well and on an engine dyno a stock LS1 with vic jr / 750holley and 1 3/4", or 1 7/8" headers will show around 400ish HP at less than 6000 rpm.
If the engine is complete and running right now, just run it. When you do a cam swap, change the rod bolts at the same time - you will be reving the engine harder with the larger cam, and rod bolts are cheap insurance.
my .02

JRracing

iTrader: (35)

There are some very good suggestions here. All of them.

I see it like this: 750-850 cfm carb, vic jr or sr intake, msd 6010 box, 220ish-230ish cam with mild lift, PAC valve springs, chromoly push rods, 243 heads or L92's, ARP rod bolts, double timing chain, ported oil pump, electric water pump.
I see a reliable 450ish fwhp.

I know a guy who custom builds carbs per app for about what they go for new. And test flows it on a comparable size. Then mails it to you. So do some home work on that.

I think a good off the shelf cam will work nice for what your doing. 224 dur cams are very solid in the mid range. Even a low 230 dur would be very strong. You can find them all the time in the FS section. And sponsors have great cams they build to your desire.

I would get a holley fuel pump. Between 90-120 gpm volume. -08 fuel line to the reg. I run 6.0 psi at the carb and have never had a problem.

You can never pay to much for valve springs. Buy top notch springs. Even if they are $500 a set... It goes back to "you get what you pay for" in this dept lol.

Absolutely get a wide band for tuning the carb. It makes it so much easier once you learn what the motor likes. And if for all the sudden it starts running lean you will notice it on the gage.

Pop N Wood

iTrader: (1)

I wasn't suggesting a Holley carb over the Edlebrock. Some guys might but I don't know enough about the Edlebrock to say one way or the other. Just wanted to point out that LS motors are a little different than a first gen to set up a carb on but still doable. I'm sure you can get the edlebrock to work.

You can't use L92 heads with the smaller bore of the 5.7L LS1 motor. LS6 heads (i.e. 243 casting number) would be a worthwhile upgrade. Used LS6 cam and valve springs can be bought cheaply enough. Those two changes alone should give you your HP goals.

Gas mileage with a carb is suprisingly good, especially if you tune with a wideband. EFI might net you a few more MPG under certain conditions, but I wouldn't rule out a carb for just that reason.

You're going to want some type of catch can or improved PCV system for that early LS1 motor. The later motors had improved blocks and vent systems to keep oil out of the intake, especially when running steady high RPM's. Maybe get a crankcase evacuation system that plumbs into the exhaust. Might help your off road machine be more reliable.

http://www.jegs.com/c/Oil-System_Cra...10449/10002/-1

Ravenous T\A

iTrader: (12)

Just copy what I did