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73-87 Chevy _ GMC Trucks => Engine/Drivetrain => Topic started by: bdog on February 11, 2009, 01:56:22 am

Title: 700 to 350 swap?
Post by: bdog on February 11, 2009, 01:56:22 am
My 83 SWB has a factory 700 in it. It looks like it may be the original tranny with who knows how many miles. I have heard stock they are just good for around 300hp. My motor I am building should be pushing 450hp.

Basically I am looking for a new tranny.

Seems like the 700's are about twice the cost of a 350. This truck is going to be for cruising around town and trips to the track. No long trips so overdrive is not important to me. If I swap over to the 350 what all will I need? Can I use the existing crossmember, cooler lines, shift linkage, drive line etc. I know the TQ converters are different but just wondering what else I need to buy and if there is any particular 350 ranny I should be looking for. A buddy told me long tail but I am not sure.

 
Title: Re: 700 to 350 swap?
Post by: 80stepsideguy on February 11, 2009, 02:37:43 am
Look on craigslist for a tranny.I bought my 700 r4 for 500.00 and the tranny goes for around a grand.I`m putting this behind a 454 big block(by the time i`m done a 468)and i was told if he wasn't so hard up for cash it would've went behind his 502 big block race car he is building.Also if you swap trannies your going from a 4 speed to a 3 speed and the rearend gears may be like 3.73 and you`ll be taching that motor out.Unless you decide to swap rearend gears as well.The crossmember will fit just need to move it i believe, gonna need to get new tranny lines, maybe even a new driveshat a the 700r4 s i think are a bit longer.A new speedodometer gear as well.

thanks
pat
Title: Re: 700 to 350 swap?
Post by: Captkaos on February 11, 2009, 11:06:15 am
A 700R4 can be built to handle about 800lb/ft and you get to keep OD
To put a TH350 in its place you have to move the crossmember towards the engine about 2" and get a longer driveshaft.  Everything else will bolt up.  I just went the other way...