Ok this is the deal. I have a 88 305 lo3 TBI motor (original) with about 146k. I am thinking it's about time for a Motor swap. I have very limited funds and need to know what type of set-up I should go with. I have a new 350 block with less that 300 miles on it. Its just a block. The crank is not good cuz the #1 rod grounded the journal. This motor came from a 1 ton pick-up. It looks perfectly new. I want to build this motor and install it in my car. SHould I go with the TBI set-up or Carb or what?? I know I need a new crank, but should I replaced that rod with a new one? or all eight. Also the pistons look good, and I think they are aluminum, can't remember. What else would I need for this motor? I know i need a cam, head, and intake, and I would perfer getting all GM perfomance parts. This is for a daily driven car, but would like for the strip as well. WHats ya'll opinion?? What would make this thing kick out some power from GM performance parts??? Thanks

 

partly it depends on your cash supply and e test or not. carb would be easer i think and offer more preformance for less work. on the other hand you wouldn't have to buy anything if you kept your TBI set up. maybe have to change the ecm or just the chip. i'd change the one rod thats bad, machine shop can check them for you. buy a new crank.

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ICON Motorsports
1st & 3rd

 

Sounds like your knowledge of rebuilding a motor and the neccessary parts required is kinda limited. You definitely need to consult with a good engine rebuilder whatever you decide to do. If you stick with the TBI, you'll need to either increase your fuel pressure, or go to the bigger 350 injectors in your throttle body. A 350 TBI prom(computer chip) from a chevy truck or the like would probably benefit you as well.



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89RS w/350 TPI; 69RS/SS w/450 HP 350/Muncie 4-Speed "Too weird to live, too rare to die."

 

All I can say is that I did the swap to the 350 K motor or LO5 (pends on who your talking to) and I dident have to change anything, I dont disagree with any other post, Im just telling you what I did. I kept the TBI set up (stock)--NJ emmissions test are brutal and frequent (road side- spots) and I breeze right through them. I think it really depends on the type of 350 that your working with and its requirements--I do sort of wish that my car was factory with a carb cause I could have done alot more with it, but it wasent, and I couldent--I am extremely happy with the new 350, and it was the GM/GoodWrench rep that turned me on to it, he did say that I would be fine with stock 305 injectors (from the LO3) but that the motor would be closest to its full potential if I increased their size up. That involves changing things that I dident want to deal with at the time like proms--possible fuel pump concerns and others, not to mention that after all the $$$ Ive dumped into this Car my wallet was light---but one cool thing is that its always an option--and one last thing that really Impressed me was that the brand new 350 gets way better gas milage then the lo3 ever did (even new), with way better power to boot---I wish ya luck and I hope this helps

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(Kill the headlights, and put it in neutral)

--George
92 RS 25th Aniv.
350 Goodwrench (NEW LO5)
700R4 Raptor: high performance intermediate billet servo, high performance overdrive billet servo,Mega Valve,13 vane high performance pump,1800 heavy-duty stall converter and a 29 element heavy-duty forward input sprag.

 

Thanks for the replys, But what I am mainly asking is if I should keep the TBI set-up. I know What i am doing when it comes to building the engine, just want to make sure that I do not mismatch parts that do not working together so nicely. I would also like your opinion about what gives the most bang for your money when it comes to buying parts such as heads, intake, cam, etc. but would like GMPP since I work for a gm dealer. I don't want to buy the GMPP crate also, I have the block and would like to work from there. Thanks again

 

Legend,

Chevy always leaves a lot on the table. All you have to do is go get it. The best place to start, in my opinion, is in the heads.

There is always room for improvement, and Chevy powertrain always errs on the side of caution and reliability. You can easily massage another 10% in HP out of almost any SBC through head and valve work. I've got a good feeling about the Fast-Burn heads and 18° high-port heads. The High-Ports require a completely different intake, so that may be limiting, but the Fast-Burns are relatively bolt-ons with aftermarket intakes readily available. From what I am reading, there is a lot of extra material for the creative port finisher to get some more flow from these heads as well, but they do a respectable job right out of the box with only minor polishing of the chambers and exhausts. Both heads are made of cast aluminum. The Fast burns should be good for at least a 25 HP gain right out of the box, even with the smaller 2.00/1.55" valves.

Since you have to get heads for your block anyway, this would probably be a good place to start.

To answer your main question a little more directly, you can keep the TBI setup, but should plan for a larger throttle body and higher flowing injectors. You might even want to consider two TBI units. Soem people have problems with this, but it really isn't that hard to make work if you know a little about the control system. After all, you really only need one IAC and one TPS sensor if the throttles are synchronized. A custom PROM would be a must, however.

And since you mentioned the camshaft, as much as I am a dedicated "Bow-Tie guy", I feel the GM camshafts leave a lot to be desired. Even the LT4 "Hot" cam and other GMPP flavors are a little bland. The LT4 "Hot" grind is supposed to be "Hot" at a meager 0.525" lift, and that's WITH 1.6:1 rockers. Most aftermarketers have grinds that exceed the performance of these designs with "standard" rocker ratios, allowing a little stagger and fine tuning of the valve train with aftermarket rockers. And while the GMPP and factory cams can pass emissions on the cars they were originally installed in, they aren't certified for 50-state emissions in our engines. Neither are the aftermarkets, but I'd bet most of us could blow the sniffer clean with some fairly aggressive cam patterns. I'm guessing you aren't as concerned with total pavement-ripping performance, but at least do a little shopping before you select a cam from the limited choices in the GMPP catalogs.

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Later,
Vader
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"No matter how hard you try you can't stop us now"
Adobe Acrobat Reader 4.0

 

Ahhh, now thats the kind of Info i like. Now with the Two TBI set-up, I would just need to splice the feed and return lines to both TBI's right? and a link to throttle flaps?? Lets just say I did something like this, my guess gas mileage would suck?????????? I just happen to have two TBI units. I like the fast burn 18 degree heads, and have been looking at them, Also the HOT cam set. Now with this type of set up (fast burn heads, HOT cam, duel TBI and a decent roating asm, chip) I should have a decent engine hum? around what hp and torque? But my only problem is that this is a daily driven car, but would like to see some kind of action. My gas mileage already such really bad!!??? SO what do you think?

 

I'm with Vader on the suggestion of the fast burn heads. From what I've read about these heads, they seem like they have some amazing potential, and the nice part is you don't have to spend a fortune in machine work to make them perform really well. As soon as they come out with a TPI intake for the fast burns, I'm seriously considering getting a set of them for my car. He's also right on the money about GM erring on the side of caution and reliability, especially when it comes to camshafts. On the flip side however, you have to be careful not to end up with too radical of a cam from one of the aftermarket suppliers. Just pay close attention to the manufacturer's comments on the power range and vacuum characteristics of each cam they offer, and make sure it correlates with street use, and you should be okay. For instance, I wouldn't suggest going any lower than a 112 degree lobe separation, or a power range any higher than about 5500=6000 rpm for a street car, especially if you have to pass emissions. Another aspect of a cam that will kill a car on the emissions test is if it has more than about 230 degrees of duration at .050 lift. Hope this helps!



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89RS w/350 TPI; 69RS/SS w/450 HP 350/Muncie 4-Speed "Too weird to live, too rare to die."