LT-1 cam in a 305 TBI??

[ryan34]

I was just looking through Third-gen.com and saw that you could put a LT-1 cam in my car . I was not expecting to see that. Well i was wondering what they would cost brand new or the part # if available. And also if anyone has done this before. I would also like to know where to get the computer redone. This is basically a future project, but its something i would love to do, I'm just starting my research on it. Thanks in advance.

[Injuneer]

I don't know if the fact that the front of the LT1 cam is "raised" and has a step, compared to a regular SBC cam will make any difference. If you want a used cam, there should be thousands of them laying around. I still have mine in the attic.

[ryan34]

Well I've read that the LT-1 cam will take the lift to just under what the stock heads can handle. Now i'm no expert but i am assuming thats gonna give me an increase in power. (of course i'll need to change the springs too) But about you're cam...how many miles were on it? Are you selling it, if so, how much.

[TraceZ]

Well I've read that the LT-1 cam will take the lift to just under what the stock heads can handle. Now i'm no expert but i am assuming thats gonna give me an increase in power. (of course i'll need to change the springs too) But about you're cam...how many miles were on it? Are you selling it, if so, how much.

Look around a while and ask nicely. I bet you could find someone to send you a LT1 cam for nothing but the cost to ship it. I've already seen one hit the landfill.

[Joe 1320]

Personally, I think it wouldn't run as well as expected. you have to remember that the TPI motors have long runners to enhance the low end torque. The cam is tuned to to work with the intake and heads as entire system. The LT-1 manifold has shorter runners as not to run out of breathing at upper rpms the way a tuned port intake does. Granted the LT-1 cam was intended for a 350, it will "appear" to be a little more radical in a 305, but I don't think it would be a good combo. My bet is the bottom end would be a little soggy, the midrange would get a nice spike in it and about the time it started to pull nice the intake would choke it off and it would lay over in the upper rpms. The biggest hurdle in this combo is the 305 cubes and the heads. This is a low rpm torque motor and should be optimized as such. You can make it a higher rpm motor, but the lack of extra cubes really cuts down on the power available as airflow increases. Remember, engines are merely an air pump.

What many people try to do is move the TPI's torque a little higher in the rpm range. They make so much low end torque that even stock, hooking up is tough. As you add bolt ons the torque really starts to crank but the problem still exists that you can't put the power to the ground. By reducing low end torque and changing the combo so that the upper rpms (above 4K) allow more breathing potential, even with similar HP levels a quicker et is produced. But..... more than just a cam is needed to do this effectively without making something else really suffer. The solution appears to be the Vortec heads and SD matched intake. You cannot mix and match parts as the heads and intake are a matched set. The result is a slight dip in low end torque but a serious boost in the mid and upper rpms. More than enough to cover the slight loss in bottom end torque. I believe there was a write up on this very topic in a previous issue of GMHTP, I'll see if I can dig it up.

[ryan34]

Personally, I think it wouldn't run as well as expected. you have to remember that the TPI motors have long runners to enhance the low end torque. The cam is tuned to to work with the intake and heads as entire system. The LT-1 manifold has shorter runners as not to run out of breathing at upper rpms the way a tuned port intake does. Granted the LT-1 cam was intended for a 350, it will "appear" to be a little more radical in a 305, but I don't think it would be a good combo. My bet is the bottom end would be a little soggy, the midrange would get a nice spike in it and about the time it started to pull nice the intake would choke it off and it would lay over in the upper rpms. The biggest hurdle in this combo is the 305 cubes and the heads. This is a low rpm torque motor and should be optimized as such. You can make it a higher rpm motor, but the lack of extra cubes really cuts down on the power available as airflow increases. Remember, engines are merely an air pump.

What many people try to do is move the TPI's torque a little higher in the rpm range. They make so much low end torque that even stock, hooking up is tough. As you add bolt ons the torque really starts to crank but the problem still exists that you can't put the power to the ground. By reducing low end torque and changing the combo so that the upper rpms (above 4K) allow more breathing potential, even with similar HP levels a quicker et is produced. But..... more than just a cam is needed to do this effectively without making something else really suffer. The solution appears to be the Vortec heads and SD matched intake. You cannot mix and match parts as the heads and intake are a matched set. The result is a slight dip in low end torque but a serious boost in the mid and upper rpms. More than enough to cover the slight loss in bottom end torque. I believe there was a write up on this very topic in a previous issue of GMHTP, I'll see if I can dig it up.

Well the only problem with that is that i have Throttle Body Injection not Tuned Port Injection , sorry you had to write so much. But what do you think it would do in my car. I've heard that the problem with TPI is that it chokes off. Will the same problem exist in mine? I will also probably be replacing the intake manifold at the same time since that has to come off to replace the cam anyway. Like I said this is a future project, I'm just doing my research.

[ryan34]

Look around a while and ask nicely. I bet you could find someone to send you a LT1 cam for nothing but the cost to ship it. I've already seen one hit the landfill.

I'll have to do that, looking from your sig. it doesnt looke like you'll be giving up your stock one?

[Benm109]

Yes, plenty of people have put LT1 cams in their 305 TBI engines (or better ones like the LT4, ZZ4, etc.). I haven't personally done it, but I know a lot of info about it. Installing the LT1 cam is not that hard to do and it's so much better than the stock "peanut" cam. You have to do one small modification to get it to work with our engines, you have to cut the dowel pin shorter because the LT1 cams dowel pin is too long. Another thing that you need to look into is how old your valve springs are. The stock valve springs can handle a LT1 cams lift, IF the springs aren't too old. A lot of times people just buy better heads like the World S/R Torquer heads or stock 305 TPI heads instead of keeping the crappy "swirl port" heads. How many miles are on your engine? Something else to think about is that your stock TBI unit will start to hold you back after you swap cams (and heads if you do that, too). You're going to have to upgrade to bigger injectors, "port" the TBI unit, also known as the "ultimate TBI mods", and get an AFPR or convert your stock fuel pressure regulator to an adjustable one. And, you are on the right track about tuning, the stock PROM can barely keep up with the stock tune, let alone any small or large modifications. If I were you, I would look into PROM burning first, and then decide if cam swaps and beyond are in your league.

About tuning, you have some options here. The best one is to learn to do-it-yourself, but it gets a little expensive (you need a laptop, ALDL cable, some form of tuning software like Tunerpro or Tunercat, a PROM burner, Moates adaptor, and extra PROMs). But, this is the best way to do it because you can tune the car yourself instead of having someone else "guess" just by knowing your mods. Another option is to use a company that burns custom PROMs, like www.tbichips.com , to burn a chip for you. But, to get the best results from them, you'll still need a laptop, ALDL cable, and software to datalog, or otherwise the company will just "guess" with your PROM and the car will never run at it's best. A third option would be a dyno tuning session with someone who can burn custom PROMs for you.

EDIT: I also noticed that you said that you will probably change the intake manifold. I would highly suggest the Edelbrock Performer TBI intake manifold. It's the only aftermarket intake that will fit perfect and accepts all the stock hardware. Some other companies make TBI intakes, like Holley and GM Performance Parts, but the Edelbrock is the best stock replacement. Of course, you can also just get the carb intake of your choice and put a TBI adaptor plate on it, which is really the best way to go, but you'll probably lose EGR. Just some things to think about.

Joe1320, you're right, GM High Tech Performance did do a right-up on a 305 TBI 3rd gen Camaro. I don't have the magazines (I think it was a 2 or 3 part series), but they added vortec heads, a better cam, an upgraded TBI unit, and some other things that I can't remember. There were a couple of threads about the article over on Thirdgen.org some months ago.

If you have any more questions, just ask.