305 to 350 & auto to manual question
Thread Starter
Joined: Jan 2003
Posts: 642
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From: Northern New Jersey
Car: 1988 Trans am GTA
Engine: corvette 350 swap
Transmission: t-5 swap
Axle/Gears: 3.27:1 borg warner 9-bolt w/ PBRs
305 to 350 & auto to manual question
hey everyone,
I've been searching for the last hour to find an answer to this but i couldn't find a straight answer so here we go:
my GTA was originally a 305 TPI automatic car, i am changing it to a 350 TPI manual. my question is this: do i need to change the ECM and/or PROM chip? if so, which ones do i need?
I apologize if this question has been put out here before. I'm just trying to straighten out my list of parts required for what i'm doing.
I've been searching for the last hour to find an answer to this but i couldn't find a straight answer so here we go:
my GTA was originally a 305 TPI automatic car, i am changing it to a 350 TPI manual. my question is this: do i need to change the ECM and/or PROM chip? if so, which ones do i need?
I apologize if this question has been put out here before. I'm just trying to straighten out my list of parts required for what i'm doing.
Senior Member
Joined: Feb 2010
Posts: 1,125
Likes: 1
From: San Diego, California
Car: Trailblazer EXT 4.2 (Firebird Form)
Engine: 5.1 4bbl
Transmission: 700R4 Mega Raptor Level 4
Axle/Gears: 2.73
Re: 305 to 350 & auto to manual question
hey everyone,
I've been searching for the last hour to find an answer to this but i couldn't find a straight answer so here we go:
my GTA was originally a 305 TPI automatic car, i am changing it to a 350 TPI manual. my question is this: do i need to change the ECM and/or PROM chip? if so, which ones do i need?
I apologize if this question has been put out here before. I'm just trying to straighten out my list of parts required for what i'm doing.
I've been searching for the last hour to find an answer to this but i couldn't find a straight answer so here we go:
my GTA was originally a 305 TPI automatic car, i am changing it to a 350 TPI manual. my question is this: do i need to change the ECM and/or PROM chip? if so, which ones do i need?
I apologize if this question has been put out here before. I'm just trying to straighten out my list of parts required for what i'm doing.
ummm... did the 350 come with a 5 speed? well you can chang the 305/350 as long as it's the same generation setup, I think it's 85-89 and 90-92, ... MAF vs MAP... however you can just swap out a few things here and there (sensors made for 350 engines) if you don't get a complete 350 engine and computer with prom from the same year as your car... everything else should be the same...
If you don't understand this very well, don't worry it makes two of us
... I'm running on fumes right now, exhausted, way past my bedtime.. ... lol Thread Starter
Joined: Jan 2003
Posts: 642
Likes: 0
From: Northern New Jersey
Car: 1988 Trans am GTA
Engine: corvette 350 swap
Transmission: t-5 swap
Axle/Gears: 3.27:1 borg warner 9-bolt w/ PBRs
Re: 305 to 350 & auto to manual question
blazer,
i'm planning on getting a rebuilt L98 engine (same as factory in 1988). no, the 350 didn't come with a manual transmission option, but i love stick shift so i'm going for it. I have a MAF set up in the car. so far i've bought all the 350 related sensors, i'm just confused about if i need a 350 specific ECM and PROM. i wrote in my notes a while back to either get a 350 PROM chip or a 305/manual trans ECM with a 350 PROM chip. Am i on the right track?
i'm planning on getting a rebuilt L98 engine (same as factory in 1988). no, the 350 didn't come with a manual transmission option, but i love stick shift so i'm going for it. I have a MAF set up in the car. so far i've bought all the 350 related sensors, i'm just confused about if i need a 350 specific ECM and PROM. i wrote in my notes a while back to either get a 350 PROM chip or a 305/manual trans ECM with a 350 PROM chip. Am i on the right track?
Senior Member
Joined: Feb 2010
Posts: 1,125
Likes: 1
From: San Diego, California
Car: Trailblazer EXT 4.2 (Firebird Form)
Engine: 5.1 4bbl
Transmission: 700R4 Mega Raptor Level 4
Axle/Gears: 2.73
Re: 305 to 350 & auto to manual question
blazer,
i'm planning on getting a rebuilt L98 engine (same as factory in 1988). no, the 350 didn't come with a manual transmission option, but i love stick shift so i'm going for it. I have a MAF set up in the car. so far i've bought all the 350 related sensors, i'm just confused about if i need a 350 specific ECM and PROM. i wrote in my notes a while back to either get a 350 PROM chip or a 305/manual trans ECM with a 350 PROM chip. Am i on the right track?
i'm planning on getting a rebuilt L98 engine (same as factory in 1988). no, the 350 didn't come with a manual transmission option, but i love stick shift so i'm going for it. I have a MAF set up in the car. so far i've bought all the 350 related sensors, i'm just confused about if i need a 350 specific ECM and PROM. i wrote in my notes a while back to either get a 350 PROM chip or a 305/manual trans ECM with a 350 PROM chip. Am i on the right track?
Thread Starter
Joined: Jan 2003
Posts: 642
Likes: 0
From: Northern New Jersey
Car: 1988 Trans am GTA
Engine: corvette 350 swap
Transmission: t-5 swap
Axle/Gears: 3.27:1 borg warner 9-bolt w/ PBRs
Re: 305 to 350 & auto to manual question
ok so i definitely need a 350 PROM. no problem. so you're saying i need the 350 computer too? i know the prom chip controls engine and transmission, but what's the ECM's role? True on the TCC since i heard it searches for a signal, but then again some people have had no problems. Its odd some people had simply just taken their autos out, put the manual parts in, and then just wired up the reverse, neutral safety, park, etc..and have no problems. looks like i'll just have to see when i get there.
Yeah i know the t5 is weak but this is only temporary to get it moving and to get it all set up. i'll do a T56 swap later. right now it's gotta move on it's own since it doesn't have an engine (hint hint) so if anyone has one nearby i'm game.
Yeah i know the t5 is weak but this is only temporary to get it moving and to get it all set up. i'll do a T56 swap later. right now it's gotta move on it's own since it doesn't have an engine (hint hint) so if anyone has one nearby i'm game.
Senior Member
Joined: Feb 2010
Posts: 1,125
Likes: 1
From: San Diego, California
Car: Trailblazer EXT 4.2 (Firebird Form)
Engine: 5.1 4bbl
Transmission: 700R4 Mega Raptor Level 4
Axle/Gears: 2.73
Re: 305 to 350 & auto to manual question
there were different number between years... I think some process the information faster than others... then I do believe one computer was used only for 1 model year...
Senior Member
Joined: May 2006
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From: NY
Car: 00 SSEi / 94 C4
Engine: 231 / 383
Transmission: 4T65E / ZF 6sp
Axle/Gears: 2.93 / Dana 44 3:45
Re: 305 to 350 & auto to manual question
you can program your 305 prom to match the 350 ,PM me I can make one up if you send your prom in exchange
Not a great choice <> but yes the T5 Can handle the 350..Make sure you purchase a good shifter!! the best is the Pro 5.0<<<<
Not a great choice <> but yes the T5 Can handle the 350..Make sure you purchase a good shifter!! the best is the Pro 5.0<<<<
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Re: 305 to 350 & auto to manual question
The best bet for the 350 5-speed is to get a 305 bin with the 350 fueling tables copied over to it. The MT vs AT is different in several areas and using a AT bin can cause stalling with a MT.
Joined: Mar 2000
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From: Littleton, CO USA
Car: 82 Berlinetta/57 Bel Air
Engine: L92/LQ4 (both w/4" stroke)
Transmission: 4L80E/4L80E
Axle/Gears: 12B-3.73/9"-3.89
Not true. See below for a better assessment.
Junior Member
Joined: Dec 2007
Posts: 28
Likes: 0
From: Temple, TX
Car: 1988 Pontiac Trans Am GTA
Engine: 350 TPI
Transmission: T-5 Manual
Re: 305 to 350 & auto to manual question
So glad someone has clarified that for me.
I have been having issues with my car from the get go. Stalling, erratic idle, loss of power over 3500rpms.
Found out after purchasing the car that it does not have the original engine in it. Vin calls for a 305, while the numbers on the block bring back a 350 10054727. While it still has the original TPI, i stretched for a new set of Injectors, complete tune up, Knock sensor, and IAC. Trying to smooth it out, still no luck.
After readin on some posts here, found that a new prog should help me out. My only issue now is the fact that there were never any 350 TPI T-5 set-ups in this year. Therefore i cannot find a prog that will work in my car. Hypertech, jets does not make any that will work with a warranty if it doesn't.
Could i get some more help here?? Thanks
1988 Pontiac Firebird Trans Am GTA 350 TPI, T-5 manual, limited slip, WS6.
Red metallic, 16" gold snow flake rims, T-Tops. Aside from Motor, all stock replacement parts.
I have been having issues with my car from the get go. Stalling, erratic idle, loss of power over 3500rpms.
Found out after purchasing the car that it does not have the original engine in it. Vin calls for a 305, while the numbers on the block bring back a 350 10054727. While it still has the original TPI, i stretched for a new set of Injectors, complete tune up, Knock sensor, and IAC. Trying to smooth it out, still no luck.
After readin on some posts here, found that a new prog should help me out. My only issue now is the fact that there were never any 350 TPI T-5 set-ups in this year. Therefore i cannot find a prog that will work in my car. Hypertech, jets does not make any that will work with a warranty if it doesn't.
Could i get some more help here?? Thanks
1988 Pontiac Firebird Trans Am GTA 350 TPI, T-5 manual, limited slip, WS6.
Red metallic, 16" gold snow flake rims, T-Tops. Aside from Motor, all stock replacement parts.
Senior Member
Joined: Feb 2010
Posts: 1,125
Likes: 1
From: San Diego, California
Car: Trailblazer EXT 4.2 (Firebird Form)
Engine: 5.1 4bbl
Transmission: 700R4 Mega Raptor Level 4
Axle/Gears: 2.73
Re: 305 to 350 & auto to manual question
you can get a custom prom for your setup.. look for member Kevin, I hear he does pretty good work... look for him in the southern california board...
Junior Member
Joined: Dec 2007
Posts: 28
Likes: 0
From: Temple, TX
Car: 1988 Pontiac Trans Am GTA
Engine: 350 TPI
Transmission: T-5 Manual
Re: 305 to 350 & auto to manual question
I could not find a "Kevin" in the southern California board. Found a few Kev, per se, but not by the actual name Kevin. How could i find the right person that your talking about??
Junior Member
Joined: Dec 2007
Posts: 28
Likes: 0
From: Temple, TX
Car: 1988 Pontiac Trans Am GTA
Engine: 350 TPI
Transmission: T-5 Manual
Re: 305 to 350 & auto to manual question
How hard is it to program a eprom yourself? I have found all of the equipment from moates.net that looks to be easy. Which is cool because i have another car that could be tuned. (although not needed)
Since i do have the original chip, i could take a snapshot of it, then add the 350 fueling tables to it, while keeping the transmission bin.
Is this correct, or is it more complicated than its worth?? For a total of 150.00 bucks i could come out with a custom tune, then revert back to the stock chip if needed.
Re: 305 to 350 & auto to manual question
How hard is it to program a eprom yourself? I have found all of the equipment from moates.net that looks to be easy. Which is cool because i have another car that could be tuned. (although not needed)
Since i do have the original chip, i could take a snapshot of it, then add the 350 fueling tables to it, while keeping the transmission bin.
Is this correct, or is it more complicated than its worth?? For a total of 150.00 bucks i could come out with a custom tune, then revert back to the stock chip if needed.
Since i do have the original chip, i could take a snapshot of it, then add the 350 fueling tables to it, while keeping the transmission bin.
Is this correct, or is it more complicated than its worth?? For a total of 150.00 bucks i could come out with a custom tune, then revert back to the stock chip if needed.
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From: Texas
Car: 1992 Formula Firebird
Engine: 305CID (LB9)
Transmission: World Class T5
Axle/Gears: 10-bolt, 4.10 gears
Re: 305 to 350 & auto to manual question
ummm... did the 350 come with a 5 speed? well you can chang the 305/350 as long as it's the same generation setup, I think it's 85-89 and 90-92, ... MAF vs MAP... however you can just swap out a few things here and there (sensors made for 350 engines) if you don't get a complete 350 engine and computer with prom from the same year as your car... everything else should be the same...
If you don't understand this very well, don't worry it makes two of us... I'm running on fumes right now, exhausted, way past my bedtime.. ... lol
If you don't understand this very well, don't worry it makes two of us
... I'm running on fumes right now, exhausted, way past my bedtime.. ... lolAs for switching to a 350 from a 305 you should only need the 350 knock sensor, larger injectors and the 350 PROM. Everything else is the same.
blazer,
i'm planning on getting a rebuilt L98 engine (same as factory in 1988). no, the 350 didn't come with a manual transmission option, but i love stick shift so i'm going for it. I have a MAF set up in the car. so far i've bought all the 350 related sensors, i'm just confused about if i need a 350 specific ECM and PROM. i wrote in my notes a while back to either get a 350 PROM chip or a 305/manual trans ECM with a 350 PROM chip. Am i on the right track?
i'm planning on getting a rebuilt L98 engine (same as factory in 1988). no, the 350 didn't come with a manual transmission option, but i love stick shift so i'm going for it. I have a MAF set up in the car. so far i've bought all the 350 related sensors, i'm just confused about if i need a 350 specific ECM and PROM. i wrote in my notes a while back to either get a 350 PROM chip or a 305/manual trans ECM with a 350 PROM chip. Am i on the right track?
You need a 350 prom if you are going to run 350 injectors, otherwise you will have performance issues... on the computer itself, I would just try and get it as well with the Prom.. I am not familiar with the changes from one period to the next... now on the Tranny, you may have to get the TCC part tuned out, but I could be mistaken... also I don't know that a t5 can handle the power of the 350, so you may have to get a beefed up Tranny... again I am not sure on that...
The 1985 ECM and wiring harness is specific to that year. It is this way with the Camaro, Firebird/Trans Am and the Corvette.
Thread Starter
Joined: Jan 2003
Posts: 642
Likes: 0
From: Northern New Jersey
Car: 1988 Trans am GTA
Engine: corvette 350 swap
Transmission: t-5 swap
Axle/Gears: 3.27:1 borg warner 9-bolt w/ PBRs
Re: 305 to 350 & auto to manual question
No, the 350 did not come with the 5 speed transmission. As for the "generations" of TPI it goes like this: 1985, 1986-1989, 1990-1992. The TPI plenum and runners are the same. The fuel rails are all similar. Though the 1985 fuel rails have the 9th injector for cold starting. The 1985 and 1986 intake manifolds have a different bolt pattern than 1987 on up heads do. The ECMs and PROMs changed more frequently however they should work within their respective years. It is best to match up the ECM with the hardware you have if possible.
As for switching to a 350 from a 305 you should only need the 350 knock sensor, larger injectors and the 350 PROM. Everything else is the same.
The ECMs are the same. You just need the PROM.
The T5 will hold up to sensible driving. It will not hold up to hard launches and ripping through the gears at high speeds for very long.
The 1985 ECM and wiring harness is specific to that year. It is this way with the Camaro, Firebird/Trans Am and the Corvette.
As for switching to a 350 from a 305 you should only need the 350 knock sensor, larger injectors and the 350 PROM. Everything else is the same.
The ECMs are the same. You just need the PROM.
The T5 will hold up to sensible driving. It will not hold up to hard launches and ripping through the gears at high speeds for very long.
The 1985 ECM and wiring harness is specific to that year. It is this way with the Camaro, Firebird/Trans Am and the Corvette.
OK, where can i get a 350 prom chip? should i go for a hypertech chip programed for 350 and manual trans? are they reliable? or should i just prog my old chip?
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From: Texas
Car: 1992 Formula Firebird
Engine: 305CID (LB9)
Transmission: World Class T5
Axle/Gears: 10-bolt, 4.10 gears
Re: 305 to 350 & auto to manual question
Hypertech chips aren't worth the money. The changes vs. a stock prom are intended basically for stock or near stock vehicles. They just aren't worth it really. Your best bet is to get a 350 PROM from the for sale section and hit up the DIY PROM section and learn to tune.
Thread Starter
Joined: Jan 2003
Posts: 642
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From: Northern New Jersey
Car: 1988 Trans am GTA
Engine: corvette 350 swap
Transmission: t-5 swap
Axle/Gears: 3.27:1 borg warner 9-bolt w/ PBRs
Re: 305 to 350 & auto to manual question
got it! thanks, WS6!
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Car: IROC Z
Engine: 305 TPI
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Re: 305 to 350 & auto to manual question
I have a 1986 Camaro tpi 305 car. I want to replace the engine to a 350. I also want to swap the auto tranny for a 5 speed. I need to know if i replace the engine harness will it plug right into the fuse block. The car i am taking the 350 and harness is a trans am gta. Will i run into problems? What is the best way of doing this? What will i need to do this swap properly??
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From: Downers Grove, IL
Car: 91 Z28 / 04 GTO
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Re: 305 to 350 & auto to manual question
TRUEGINO make a new thread, this one is several months old.
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