91WhiteCamaro

hey all, i have a 1991 RS with 305 and thinking about changing it to 350. if i do swap it out, should i go Carb or TPI? what are the benefits of one over the other? any words of wisdom will come in useful

Codename 47

iTrader: (4)

Well it depends. TPI does not flow well. If your really going to build up your 350, you'll probably want to use a holley stealth ram or some other fuel injection system. It's gonna run smooth, start easy, and be efficent.
Carbs are cheap, but not as efficent as fuel injection. It's a preference thing. With a carb you'll also get worse gas mileage. It's been said you can build a faster motor cheaper by going the carb route. I think I saw a article in Chevy High Performance about a budget build up where they built a carbed 350 that put out 400 hp and only spent 2500 bucks on it.

1981LT1

iTrader: (1)

True. TPI units take alot of money to get to flow anywhere near being great on the upper rpm level. Although, the TPI has pretty good torque down low. Plus, I personally love the look of the runners and the plenum when they are cleaned and maybe even polished or painted. It's all in what you want and how you want to use it.

five7kid

iTrader: (14)

Stay with TBI.

91WhiteCamaro

TBI? i was thinkin of going Carb but this is my goal and i've seen many posts with u in it and u seem to know exactly what your talking about Five7. where i live, almost 90% of the cars around here are hondas and Integras. I was raised on american muscle in my family so naturally i went the good route. well it just eats under my skin when people drive by in there hondas goin about 50ish and with a fart can on there exhaust. i want a car that at any moment i can step on the gas and show them whats up. that is my main goal for now because im only 16 and theres only so much money i can make and so much time to spend. also at the same time, i dont want to be getting horrible milage. i was also reading that Getting an LO5 is the most horrible way to go because of there very crappy cam and heads. A friend of mine can rebuild an engine with me (he knows what he's doing) so i figured i could just go to the junkyard and get a 350 block?

Codename 47

iTrader: (4)

Going fast isn't cheap. Personally, I'd go carb if your on a budget. Your not gonna get as good of milage but it's cheaper to start off with. Your right, ditch the 305, get a 350. You will see more bang for your buck with the 350.

Nice thing though is you can get a 350 block bore it out, do everything on the low end right the first time: get some decent forged pistons or something, so you can spray nitrous it if you want. Then you can always just put your 305 heads, cam and intake on it. Later once you get more money you can find a set of vortecs and a decent cam ect.

Like I said though, going fast isn't cheap. Once your car starts getting some serious power, your gonna need to start fixing parts that your gonna break, like your tranny and rearend.
-Greg

91WhiteCamaro

ok so now its down to Carb and TBI, so I'll look more into each and which will give me more for what i want. The only mods im going to be tackling soon are Headers, Exhaust, and a new induction system (and the 350 of course). after those, I'll get into more serious things. is there a certain 350 i should go for? if i were to just get any 350 block and rebuild it would that be fine?

five7kid

iTrader: (14)

TBI is the poster child for factory underachievement. There's nothing wrong with the concept, it's just a feedback system for injecting fuel into the airstream. A carb must use the airstream to draw the fuel into itself, an inherent weakness. Since carb technology had about an 80 year jump on EFI, small wonder it is cheaper to switch to. However, you wouldn't be switching to TBI, you'd just be modifying it.

Spend some time over on the TBI forum to see what can be accomplished with it. It still suffers from underdevelopment, but for a street driven car that already has it, modifying it will produce better results overall for the same money than switching over to carb.

Think about it - TBI was developed to meet CAFE fuel efficiency and EPA emissions requirements. The LO3 (and LO5, for that matter) was saddled with power-robbing swirlport heads. Eliminate the swirlports, improve the TBI system for power, and it still retains its efficiency and emissions capabilities.

It is worth considering.

five7kid

iTrader: (14)

Something else to consider: Holley's first stand-alone EFI conversion system was TBI. Yes, different than what GM did, but still the same concept. If it is such a rotten idea, why would Holley waste their own money to develope one?

Codename 47

iTrader: (4)

Great point five7kid. I'm changing my opinion. You might aswell work with the TBI. If you find you absolutely can't handle having it on your car you can always take it off and go carb or someother route. But atleast you took a shot with it. I mean since you've already got it you might aswell try it. Right?
-Greg

91WhiteCamaro

ok, cool. well im getting a 350 from a local junkyard for christmas, and rebuild it (good idea?) and will my TBI fit on it? it won't be on for long, but just temp until i buy either a bigger TBI or Carb. what all do i need to look into getting for the 350? where on the engine is the displacement number too, so im not going off someone elses word at the yard, so i can check it myself.

five7kid

iTrader: (14)

The casting # is on the bellhousing casting, behind the driver's side head. Some also have "5.0l" (305) or "5.7l" (350) cast there as well.

Rebuilding it depends upon what, if any, warranty comes with it. If they say they'll guarantee it for 30 or 90 days or something, but you rebuild it (or even open it up), warranty void. If no guarantee is offered, a compression check will give you some pretty good info.

If you get a B-body (Caprice or Roadmaster), truck or van 350 from mid-80's to early 90's, it will already have the 350 TBI on it. You may even be able to use the PROM from the computer. Again, spend some time on the TBI forum for that information.