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305 TBI to 350?

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Old 02-11-2008, 01:09 AM
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Car: 88 Camaro
Engine: 305 TBI
Transmission: 700-R4
Axle/Gears: 2.73
305 TBI to 350?

88 camaro
305 TBI
700r4
I have a question for those who have done the 305TBI to 350 TBI/TPI swap. Would TPI benefit me more then the TBI? also is TBI turbo'able ? or just do TPI if i decide turbo's ? One more question, Where did most of you get your engine? Did you suck it up and buy crate, or did you find a junk yard get the block, throw some heads and cam in it ? And around how much you paid.. ? Thanks in advance for reply's!
Doug
Old 02-13-2008, 12:12 PM
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Car: 88 Camaro
Engine: 305 TBI
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Axle/Gears: 2.73
Re: 305 TBI to 350?

bump
Old 02-13-2008, 09:51 PM
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Re: 305 TBI to 350?

this is exactly what i need to hear because im doing the same thing
Old 02-19-2008, 01:51 PM
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Car: 88 Camaro
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Re: 305 TBI to 350?

but its the deadest post go figure huh
Old 02-19-2008, 01:55 PM
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Re: 305 TBI to 350?

I'm getting a 350 TBI dropped in and I might install some minimal upgrades. But when I go forced induction I will swap out an EFI system. Its just much easier to deal with than a TBI system. But, for daily driving and a small bit of street-ability a 350 TBI wouldn't be so bad with some bolt ons. And its cheaper than the equivalent TPI. Or at least I believe it is.

By EFI I'm talking about a BETTER fuel injection system. YES TBI is technically fuel injected--it just isn't as effeciant or desirable for forced induction.

Last edited by VonKaiser; 02-19-2008 at 05:48 PM.
Old 02-19-2008, 02:08 PM
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Engine: LS1/LQ4
Transmission: 4L60E/4L80E
Axle/Gears: 12B-3.73/9"-3.89
TBI is EFI. So is TPI.

Sorry about the lack of response, it was a busy time in my life.

TPI will increase torque somewhat over TBI, and therefore power, but the big difference wasn't the induction system but the heads, cam, and exhaust.

Swirlport heads, whether 305 or 350, are great for low RPM operation, clean exhaust, and good fuel economy, but really fall off when cam lift is increased and RPMs go up - and what do you do to increase power? Increase cam lift and RPMs.

Cam is an easy one, but if you're keeping TBI heads, you need to keep the lift down.

Exhaust is a no-brainer - change it all.

TBI is a speed density system. Only the '90-'92 TPI systems were SD. Theoretically, it doesn't much matter which system you supercharge, as either one will work. You'll need to do a bunch of things to get either system to respond properly. It's just that TBI was never really pursued by the aftermarket.
Old 02-19-2008, 05:47 PM
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Re: 305 TBI to 350?

Originally Posted by five7kid
TBI is EFI. So is TPI.
By EFI I simply meant a better fuel injection system. TBI while technically fuel injection is not very effeciant or desirable for forced indution as you may know.
Old 02-19-2008, 06:08 PM
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I assumed you meant an aftermarket fuel injection system, perhaps there's a brand name "EFI" out there, I don't happen to know whether there is or isn't.

I just didn't want anyone to get the impression that TBI is not "electronic fuel injection".
Old 02-19-2008, 08:36 PM
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Re: 305 TBI to 350?

Originally Posted by five7kid
I assumed you meant an aftermarket fuel injection system, perhaps there's a brand name "EFI" out there, I don't happen to know whether there is or isn't.

I just didn't want anyone to get the impression that TBI is not "electronic fuel injection".
I should of been a little more specific. I assumd that everyone knew by now that TBI was fuel injected. I'm hoping to find a good aftermarket EFI system or something that would work on the 350 I get. Would an LT1 EFI system work? I'd imagine since I'll be getting a crate 350 installed that it might with some work done to the ECU. But please correct me if I'm mistaken.
Old 02-20-2008, 12:24 AM
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Car: 82 Berlinetta/57 Bel Air
Engine: LS1/LQ4
Transmission: 4L60E/4L80E
Axle/Gears: 12B-3.73/9"-3.89
LT1 systems work best on LT1's. And, IMO, LT1's work best with LT1 systems.

For what you can get good running LT1 systems these days, it makes a lot of sense to me to just go for the LT1 and skip the Gen I 350 phase. Not so hard to swap, you could argue no more trouble than getting the TBI to work properly with a 350. Power adders are very common on LT1's. Economy and tuneability are improved with the LT1 as well.
Old 02-20-2008, 08:11 AM
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Re: 305 TBI to 350?

the tbi in my oppinion sucks, and the tpi is just as much wiring, i hate wires, and injectors and crap, shove a carb on it, go to edelbrock or advance or some car show, buy an intake, carb, distributor, wires and that, and have more power than a tpi will handle, haha, thats what i call a real engine (not saying camaro made a mistake with tpi), i just perfer carbs, but if u want tpi, choose it over tbi
Old 02-20-2008, 10:14 AM
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Transmission: 4L60E/4L80E
Axle/Gears: 12B-3.73/9"-3.89
TBI never got its due. It isn't a fatally flawed concept - the Holley Pro-Jection is a TBI-type standalone EFI system, so it can't be that bad. Speed density does offer tuning capability that you don't necessarily have with MAF, so it isn't fair to say that there's no hope for TBI.

You just have to be committed to making it work.

"Just shove a carb on it" is the right answer in about 5% of cases.
Old 02-20-2008, 06:21 PM
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Re: 305 TBI to 350?

Originally Posted by five7kid
LT1 systems work best on LT1's. And, IMO, LT1's work best with LT1 systems.

For what you can get good running LT1 systems these days, it makes a lot of sense to me to just go for the LT1 and skip the Gen I 350 phase. Not so hard to swap, you could argue no more trouble than getting the TBI to work properly with a 350. Power adders are very common on LT1's. Economy and tuneability are improved with the LT1 as well.
The cost for me to intially get an engine put in my Camaro would be a whole bunch more if it was an LT1. Right now I'm interested in the cheapest alternative with some drivability. Locate me a good performance EFI system that can be bolted on the 350 I get and that's all I'll ever want. TBI's do make good power and torque--but it costs money and time. But I suspect since this is a create motor it should have a good power output right out of the box, so all I'll really need in the short term is the 454 TBI system and a good intake with a good set of headers.
Old 02-20-2008, 06:24 PM
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And some PROM tuning.
Old 02-21-2008, 10:46 AM
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Re: 305 TBI to 350?

I just picked up a 350 tpi with 78,000 original miles out of a 88 trans am GTA with the computer and harness, for $400 off craigslist.com I currently have a 305 tbi that I will remove and replace with the tpi. My question is, some of the wires on the harness have been cut and the previous owner labeled them and it looks like it says "ALDL" on a few of them. Do these go to the port under the steering wheel and will these be the same color coded wires as my tbi? Iam assuming that the only real difference in the wiring will be under the hood. Am I correct for assuming this? All the wires that go under the hood have clips or they are grounds. I just want to make this swap as easy as possible. And I too hate wires but I wanted to try this out. My other cars are all carburated, like a 74 Corvette and a 71 Challenger.
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