I have looked thru the fourm to get a good idea for which cam to run in my car. As I looked thru I just got more confused. What is lo3 or lo5, are you able to run a LT1 cam in a 305 T.B.I engine. I f so what do you have to do to get it to run right? I don't have to worry about emissions, just H.P. on budget. Thanks for any help.

 

i have a crane 2040 computer cam 4 sale. 2 seasons use. 210/216 @.05 114 LSA. peak HP 5000 rpms in a 350. $45 bucks plus shipp

 

LO3 is GMs code for the 305 TBI engine, LO5 is the 350 TBI used mainly in trucks I believe but also in some cars. You can use an LT1 cam in your engine but will require computer tuning for it to run right.

 

Ronny,

Tell him what that cam will do for him in that 305. In other words, how is it better than that stock cam (we all know how bad the stock cam is so pile it on).

 

i dont know. i have a 350 and did phase 1 mods all at once. too many variables. check crane website. what are specs of stock cam? that will tell your something. same with LT1. what are specs?
my current set up runs OK.

 

I was thinking about running a Crane Cams Saturday Night Special cam kits. the Specs on the cam are duration is 282, lift .470. I called to get the computer e-prom reprogrammed and it was $250, I thought that was expensive.

 

You mentioned HP on a budget, and no emissions. This is a TBI board, and I'm TBI as well (for now), but...

I've been there, and done that, and I'm switching to carb soon. I spent alot of time and money, and all I finally got was "running but not right" because I can't get chips programmed without spending a fortune. I think my 305 upgrades have alot that's getting held back by the chip. Changing almost anything on a TBI car means chip programming. Everyone says it's easy, but I looked into it and it's beyond my available time to learn. And your right - $250 to get a chip made, which will take months of data collecting and sending data to someone that will in the end, never get it right, since they never actually drive your car themselves.

With no emissions, why not think about carbs?
Carb means getting a carb, a distributor, and a fuel pressure regulator - then your free to spend time and money on improvements you can see, versus waiting months for chips that will, in the end, just get you moving again.

I applaud everyone that has the time, money, patience for the chip thing - wish I did - but in reality I'm not looking to have the best of anything, just a small and decent thrill every so often that I can call my own work.

Check into the sticky on the carb board about switching, look into the cost. And think it over - spend months and dollars getting SOMEONE ELSE to make your car just run, or converting to something YOU YOURSELF can do, and adjust, and fix, without waiting on another person. I decided I don't want to be a TBI guru, I want to work on my ride myself, and enjoy the satisfaction that right or wrong, it's my effort I'm driving - thus I'm switching.

 

if you do cam you'll have to do heads and intake too. They all suck.

-chillen

 

wow, alot of generalizations here. Ok here's the skinny on cams to the best of my ability.

There are three things to look at when selecting a cam, duration, lift and lobe seperation.

Duration--- There are two ways to rate duration, advertised, and .05 lift duration. Advertised is a little hokey because the cam companies use different lift points to start measureing duration. .05 lift duration numbers are the industry standard and what I use to compare cams because the starting and ending points for measuring lift all start and end at .05 lift. So what do the numbers mean? A stock l03 cam has around 190 deg of duration (guess) which means the cam holds the valve open for 190 deg worth of cam rotation. A mild performance cam like a LT-1 cam holds the valve open for around 203 to 206 deg. This is a nice improvement over stock. A slightly hotter cam would be in the 210-215 area and a high rpm monster would have something in the 220-230 range. Keep in mind this is what defines your power band. Also engine displacement influences how a cam reacts. A 350 will need ruffly 10 deg more duration than a 305. So my 218 int. 226 exh. cam in my 350 would act like a 208- 216 cam in a 305. I make peak power at around 5000 rpm and shift at around 5600 -5800. Keep your power band realistic, I needed a mild 2000 rpm stall converter to get around the low torque loss my cam. The car would launch with no wheel spin then light the tires up 20 feet out of the hole, with the mild stall it pulls hard from a dead stop. Anything bigger and I would need a higher stall. I would actually benefit from a higher stall now, but this one is the best compromise between race and street for me.

Lift-- This is pretty simple, this is just the amount that the valve is opened. The more the better, to a point. You have to take into acount that most stock heads won't take much more than .450" lift. I tell people to start checking for spring retainer to valve seal clearance after this point. Most heads are good to .460 but castings are inconsistant and you don't want to have problems here. You'll see that lift goes up with duration. Because the valve is open longer you can open the vavle further. Roller cams have more lift than a flat tappet cam because the roller allows them to open the valve faster, hence why they are the big craze right now.

Lobe Seperation--- This is the angle the intake and exhaust lobe on the cam are from each other. The narrower the angle the longer the intake and exhaust valves will be open at the same time. Keeping both valves open at the same time tends to promote scavenging at certain engine speeds, the down side is you get reversion at other engine speeds, mostly low rpm's. This doesn't really hurt anything until you throw computers into the mix. Your ecm won't know about this reversion and won't know to change the fuel mix to compensate, more on this later. Most cams are ground on 108-114 lobe angles. The narrower the angle the lopeier the cam will sound. The wider lobe sep angles also tend to give you a broader power band with less peak power, they also give you a much smoother idle. "compu" cams are nothing more than mild cams with a wide lobe sep angle.

Your ECM and you--- LOL, never thought I'd get to use that line. All this cam info is great, makes you want to get a nasty 230-240 cam and run your engine to 7 grand nascar style. Untill you realize your ecm is just gonna freak with anything more than a cam in the 200 duration range with a wide lobe sep of 112--114. The reason for this is that cams effect the vacume your engine makes, your ecm basis all it's fueling off of vacume via the MAP sensor. So to fix this chip tuning is the only option. You can recalibrate your "VE" curves to match the characteristics of your new cam. Mail order chips just can't acount for all the variables that go into building a good "VE" curve, every engine is different. Even with a mild cam and a wide lobe sep your not going to get the full benefit of the cam without tuning. It's just a fact of life.