MY itty bitty 305 is dying.....slowly.....its got a bad valve seal, and some other problems, so we are going to be getting a beutiful 350 for her VERY soon. I have two options.

option 1: Someone I know is selling his LT1 TPI setup out of a 4thgen camaro with wiring harness, and the whole kaboodle for 1200 bucks. He is getting a 383 stroker put in his.

option 2: (got a price quote) I could get a 350 block down at the local machine shop blanced, cleaned, honed, bored, machined and all those other goodies, about 375 horses, short block for about 1800, long block for about 2400....high performance internals. Now if I go this route, I gotta throw a carb on it which I know will kill my gas mileage and also an intake manifold with a smog provision on it.

which would be the best for the money? the LT1 setup looks nice cause its got everything, TPI engine harness, wiring, etc, but then we have the more powerful engine for a bit more, with a carb.....


decisions decisions......


any ideas?

I'm leaning toward option number 2 but let me know whatcha all think!

thanks,
X_Wolf

 

who says a carb will kill gas milage. its how it is tuned. Also with carb there is many more choices for cam, and about everything else. just stay the he!! away from edelbrock.

 

and man that looks clean and straight. and those rims are awesome.

 

option 1: if it's a LT1, it's not TPI. They're 2 completely different things. The LT1 does not come with a TPI harness, it comes with a LT1 harness.

option 2: here we go again with the gas mileage myth. Whatever your gas mileage is now, I'd bet it's possible to do better than that, with a carb. There's also no law I have ever run across that says you "gotta" put a carb on a 350. And of course the "smog provision" thing is a myth too.... lots of carb intakes have "smog provisions", to the extent that an intake can have such a thing.

Where do you live? What are the smog laws in your area? That will have a profound impact on what you can, can't, must, & must not do.

1 valve seal = $.88 (1 set of 16 = about $14). Not what I'd call "requiring" a motor swap, in economic terms.

Where are you really wanting to go with all this? Do you have any specific goals, budget, plan for the car as a whole (read: crappy gears and torque converter), etc.?

 

well as said, there are other problems and it has high mileage, so we are just going to be placing a new engine in it, so there are no more major repairs left. the tranny and torque converter is designed for high output, cause when they were rebuilt they had high perf parts placed into it.

Ok learning time: the LT1 engine doesn't use TPI intake? I'm confused.

As far as carb, thats the best with what I could do with the 350, I have the TBI setup right now, and without replaceing the unit it'll be weak (at least from what i've read).

How can the smog provision thing be a myth? It must mean something if it is put on certain carbs/intake manifolds.

I personally live in an area whereas of at the moment, we don't have any sort of smog laws. I don't know if they will be coming or not, but there is no issue with that as of yet.

Where I am going with this: A nice powerful streetable camaro which has plenty of get up and go but definately not for racing as I do not do that. Goal is 350-375 HP and comparable torque. Gears could be an issue, but that comes when I get to it.

Thanks for the comment on the wheels. the car is very nice and very clean, except for the left corner of the dash (like every single 3rd gen I have ever seen) and the right wheel well has some damage, but we're fixing that soon too!

Oh yeah, why stay away from edelbrock. Everyone I know thats ever had em, and plenty of engine builders and authors love them!!

ok take it easy, thanks!

 

for the intake...smog regulated intake manifolds have to have EGRs on them. i belive that lowers the hydrocarbons count?

the edelbrock performer intake is good but the carbs suck. we couldnt get one to tune on my car so we just stayed with the quadrajunk. ive heard of others that had problems with edelbrock carbs. i believe that vader(one of the mods) hates them also. i read a lot of his posts and i personally would take his word as gospel.

the LT1 fuel injection is completly different from TPI but i know little about FI.

350 hp is a good deal of horsepower. a lot more than most people on these boards. gears would be a good idea. i have 2.73's and hate them. good luck with the engine build.

 

lol you hate your gears. Well wheres hould I look for good info on good running, strong, gears?

I need some info on that before deciding, but ya the engine build isn't all that expensive, so it sohuldn't be bad. Thanks for the EGR info..

take it easy.

 

i think that if i put 3.73's and positraction i would take away a lot of the problems my car has. like weak acceleration and spinning one tire and bogging for a second when the throttle is slammed.

edit: do a seach for the gears. a lot of opinions have been made about different ones. ask someone that has some experience in them what would be good for your setup. do a search in the tranny/drivetrain forum.

 

any idea where I could look for info on how gearing works? I have an idea from reading, but I need more concrete reading on what gearing does what and why. thanks!

 

If you can get a LT1 setup for 1200 bucks jump on it. LT1s respond nicely to mods. The PCM can be easily tuned for optimal performance.

The LT1 uses a different F/I setup than TPI. With the exception of a few early models they employ sequential fuel injection technology.

In essence this means that the engine can percicely optimize fuel/air mixture for each cylinder independantly. Whereas the TPI system was calculated ratios in a batch. TPI was also restrictive in terms of high RMP breathing. This issue was also addressed in the design of the LT1. The LT1 uses a completely different intake manifold. If you look at pictures of both engines the difference is quite apparent.

Lastly, the ignition system uses an opti-spark system instead of a distributor. Again, more percice timing is achieved. I once read an article that stated that it can even account for torsion in the crankshaft. Unfortunately, this is the only real weak point of the LT1s design. Optisparks fail when they get wet. Gm addressed this issue by venting the optispark in 1995. Now there are several aftermaket vendors offering replacement solutions as well.

350-375 hp is easliy attainable with the LT1. These engines were producing 260-300 hp from the factory. The LT4 was conservitively rated at 330. Again, there are several vendors offering cam and head solutions that will get you to your target without sacrificing streetability.

 

The LT1 engine doesn't use the TPI intake. It uses the LT1 intake. The LT1 one is a completely different design from TPI; it's what should have been used all along on performance cars instead of TPI. TPI should have been relegated to trucks of some sort.

TPI uses "tuned" (the T in "TPI") runners which are of a specific length, chosen such that the pulse of sound (pressure) in one runner resulting from the incoming charge slamming into the back of the intake valve as it closes, reinforces the next cylinder's fill event. Any sort of tuning like this only works over a relatively narrow band, in the case of TPI it's from about 3200-3800 RPM; efficiency at all other RPMs is sacrificed, especially at any RPM above about 4400.

The LT1 intake is a little low thing with very short runners. It does not use acoustic tuning. It's a simple, stratight-ahead, dry-flow port injection system. However, the LT1 motor also doesn't have a distributor in the same place as the original SBC's is; instead it has OptiSpark which is mounted on the front of the engine between the water pump and the timing cover, and is driven directly off the cam. Since it has very short runners, it has very low restriction, and correspondingly good high-RPM flow (HP) potential.

The only part of the intake proper that has anything to do with smog equipment, is the EGR system. Many carb intakes (including stock ones of course) have that. The "myth" is that if you use a carb it can't pass smog. That's true in some places, for example in Califoria, where you can't put an engine into a car that's older than the car, and the engine must retain all emissions features of either the engine or the car, whichever is newer. It isn't necessarliy true in all localities since it's almost always possible to get a carbed motor to pass a sniffer test.

Gears should be part of your plan. They determine what RPM range the engine will be operating in at any given time. Don't make the typical newbie mistake of thinking that by unbolting and re-bolting big things that you see right when you open the hood, that you will necessarily make your car faster. You can dramatically improve your car's performance (note that I said "car", not "engine") without doing anything that is visible to the eye. And without doing those things (gears, torque converter, cam, heads, exhaust), no amount of big shiny chrome stuff sticking out the top of the hood will do your car any good. In fact, people frequently make their car go slower, by doing exactly that; if you change the car in ways that detract from what it's good at, but which aren't allowed to fulfill their purpose because of other limitations that still exist in the car's parts choices, you can end up with a net decrease in performance as the reward for spending your money.

 

wow nicely put. you should write a tech article for the differences between LT1 and TPI intakes

 

well that helps explain alot. I'll have to check into that engine then eh?

thanks for the info!! take it easy...

 

ok called on the engine. It is out of a 95 impala SS. I was just reading on that and some sites suggested that because it usese Steel heads instead of aluminum like the Z28 and corvette, that it might have some problems with certain cam shafts and rockers? Why would that be? Also is that engine worth the trouble? or would it be more wise to have one built/machined from the ground up?

thanks!

 

For that price I still think it is viable. The Impala SS was laying down around 265 hp stock. I am not sure about the rockers. I am sure there are guys who have been successful moding these engines. I would check out the Impala SS boards to get more details.

Otherwise, you can get a set of LT4 heads and a hot cam and you will be in business. I bet they might take 1000 for it. You also need to make sure that you have the PCM and harness if you decide to go this route.

 

yah hes selling every last bit of it with it. wiring harness, wiring itself, computer, ecm, all that crap. Pretty much the whole damned thing.


I would think that it would be fine with different cams and rockers and springs ( cause thats really the only difference ) I odn't see how aluminum heads differ from the iron heads other then the fact that the iron heads are heavier.

thanks!

 

Go 4 it!

 

Here is another great choice!

http://forum.ls1truck.com/index.php?...t=0&#entry2273

 

Tearing apart what is bound to be a valuable collector car someday to put in an inferior system. If not soon, some day he'll regret it. Oh, well, it's his car...

EGR lowers nitrogen oxide compound emissions, not hydrocarbons.

No open-loop carb will ever cover all the operating conditions as well as a well-designed closed loop, dry, injected system can. As for fuel economy, the fuel goes from a high pressure to low through a small orifice in an injected system, which produces more of a vaporizing effect than a suck-it-into-the-stream carb system can possibly have.

TPI runners tune the pulse of each cylinder, not the next one to fire. Nothing new to the concept - tunnel ram, velocity stacks, etc.