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5.0 Litre to 5.7 Litre Conversion

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Old Nov 5, 2008 | 01:21 PM
  #1  
BC GTA's Avatar
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From: Victoria, British Columbia
Car: 1989 GTA
Engine: 5.0 TPI
Transmission: T-5 WC
Axle/Gears: Yukon 3.73
5.0 Litre to 5.7 Litre Conversion

I was wondering if installing a 5.7 litre TPI engine into a car that was originally a 5.0 litre TPI car with a manual T5 world class transmission would present any problems. I have researched what needs to be done for this conversion including a 5.7 litre PROM; however, 5.7 litre engines did not come with manual transmissions. I know about the extra torque from a 5.7 litre engine that puts a strain on a T5WC transmissions. Will the 5.7 litre PROM designed for an automatic transmission need anything special done to it when used in combination with a manual transmission? Is this something that is addressed by burning a new PROM? What about if you installed a T56 transmission in place of the T5WC with a 5.7 litre engine, would this need anything special done?

I was not sure which board this should be posted on so I posted it here. I have done a search on this point but could not find an answer to this particular issue of converting TPI engines.
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Old Nov 5, 2008 | 06:47 PM
  #2  
gta87ls1's Avatar
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Joined: Mar 2006
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Car: 1987 Pontiac GTA
Engine: 350tpi
Transmission: t56 6 speed
Axle/Gears: 3.70
Re: 5.0 Litre to 5.7 Litre Conversion

I have done this swap but I put in a 6 speed instead of the t5. As for the prom I have both a stock 350tpi auto prom and it seemed to idle strange like much higher then what it should be like around 1200rpm's it would stay at. I also got a chip from www.tpichips.com and told him exactly what I had and what I wanted to keep working and shut off . I kept everything working like egr and air and he told me it was a tune for a corvette with a manual. The tpichips prom seems to work great so you may want to think of talking to him.

Last edited by gta87ls1; Nov 5, 2008 at 06:51 PM.
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Old Nov 7, 2008 | 01:31 PM
  #3  
Kevin91Z's Avatar
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From: Orange, SoCal
Car: 1990 Pontiac Trans Am
Engine: 355 TPI siamesed runners
Transmission: Tremec T56
Axle/Gears: 12-Bolt 3.73
Re: 5.0 Litre to 5.7 Litre Conversion

There are some things in the manual trans chip that cant be changed in the automatic trans chip. Its my opinion you should start with a 305 5-speed chip and have it changed to work with the new settings in your 350. That's what I did.

The biggest problem with using a Corvette chip is they have an oil temp sensor that is monitored by the computer. You'll get an SES light all the time for that if its not programmed out. I went thru that at first with my setup.

Either way you do it, it'll require a custom chip.
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Old Nov 7, 2008 | 02:45 PM
  #4  
BC GTA's Avatar
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Joined: Nov 2003
Posts: 388
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From: Victoria, British Columbia
Car: 1989 GTA
Engine: 5.0 TPI
Transmission: T-5 WC
Axle/Gears: Yukon 3.73
Re: 5.0 Litre to 5.7 Litre Conversion

OK thank you for that. I got the impression from the following article that you needed to change the PROM.

http://tpiparts.net/305_tpi_to_350_tpi_conversion

However, that does not appear to be the case.

So in my scenario I could continue to use the original 5.0 liter PROM if I installed a 5.7 liter engine with a manual transmission. However, I would need to get a new chip burnt in such a case with or without upgrades to the 5.7 liter engine such as: a cam, headers, heads, boring out the cylinders, bigger fuel injectors (which are needed anyway), etc.

Do you have any comments on the above noted article? Thanks
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