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vortec 305 to 350 swap
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okay i used to post on this forum on a daily basis back in the old days with the other style forum. i have a 98 sierrra with a 305 and orignal tranny 140,000 miles (oh and 100 shot of nitrous, hypertech, every bolt on) , and a stock 99 yukon with 60,000 on the motor and a fresh rebuilt tranny, i want to swap the motor and trannys from one to the other. i know everything will bolt right up, my question is about the electronics. i know i cant swap pcms, becasue every pcm is programed with the vin of the car it came in. my plans are to trade in the yukon just after the swap (ya i know). so it will probably run fine with the 350 ecu, it might run a bit rich but other than that everything is the same. now on the truck that i will be keeping, i already have a hypertech, i might end up selling that and getting the pcm retuned. but will the 350 run with the 305 pcm, or do i need to retune before i can drive it?
thanks for any replys
i will try to post pics of my truck, i havnt posted pics on here in over a year.
thanks
mdweiss

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Post Re: vortec 305 to 350 swap 
mdweiss wrote:
okay i used to post on this forum on a daily basis back in the old days with the other style forum. i have a 98 sierrra with a 305 and orignal tranny 140,000 miles (oh and 100 shot of nitrous, hypertech, every bolt on) , and a stock 99 yukon with 60,000 on the motor and a fresh rebuilt tranny, i want to swap the motor and trannys from one to the other. i know everything will bolt right up, my question is about the electronics. i know i cant swap pcms, becasue every pcm is programed with the vin of the car it came in. my plans are to trade in the yukon just after the swap (ya i know). so it will probably run fine with the 350 ecu, it might run a bit rich but other than that everything is the same. now on the truck that i will be keeping, i already have a hypertech, i might end up selling that and getting the pcm retuned. but will the 350 run with the 305 pcm, or do i need to retune before i can drive it?
thanks for any replys
i will try to post pics of my truck, i havnt posted pics on here in over a year.
thanks
mdweiss


Hey man , havent heard from you in a long time. Welcome.
98 and 99 pcms are interchangeable. The 350 will run on a 305 PCM but may be lean, PCM will compensate as much as it can. I am running a 97 350 with a 96 6 cylinder PCM, reprogrammed of course.

I think you could get away without a program. Talk to some of the tech's here, you might be able to get a dealership to reflash your 350 program into your 305 pcm, they just go on their GM computers, input your VIN download the 350 program by VIN into the Tech 2 then throw it in your 305. Your Hypertech I beleive is VIN locked, so it may not work if the VIN's dont match.

A tune by Ed Wright, Nelsons or Westers up here in Canada, would avoid all hassle. Because of all of your bolt ons, the Hypertech probably isnt ideal for your setup, unless it is a full custom tune, which it isnt, unlessyou took it to Hyper. and dyno tuned it there. I would sell the Hypertech, the other PCM tuners are not VIN locked and then you can completely remove torque management which is a huge improvement. I dont beleive the hand held programmers remove torque management, at least not to the degree in which a PCM guru can.

CU
HOG

Hog

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You will need to remove the Hypertech programming in order to keep the programmer 'alive' in order to sell it. The programers have different part numbers from year to year back then so it won't work on the other truck, I believe. Not sure if Hypertech will update the unit for you.

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