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-   -   350 turbo to 400 turbo swap in lemans?? (

mtmniles 03-22-2003 04:54 PM

350 turbo to 400 turbo swap in lemans??
I have a 67 lemans that has a 350 turbo in it that went out the other day, does anyone know if a 400 turbo is a direct bolt in or will I have to change out the crossmember and driveshaft??? Thanks for any help.

airworld2 03-22-2003 05:19 PM

yes transmission will bolt up, as long as its a buick ,olds or cadillac transmission. move cross member back holes should already be in that frame,if not drill out holes as need drive shaft is the same lenth if you use short tail 400 change u- joint and yoke if you have a good parts store old part number precision u joint 372 might be inter change with other u joint manufacter number need to change fill tube and dipstick,relocate vaccume line to mogulator 03-22-2003 05:31 PM

the short tail 400 is about 3" longer than the regular 350 turbo.
Also you will have to fabricate a kick down switch (electric) to downshift the 400.

[ March 22, 2003: Message edited by: ]</p>

airworld2 03-23-2003 04:13 PM

you can also install 200 r4 in the same place as your 350 and get better gas mileage drive shaft fits the same. install filler tube and dip stick from delta 88 cable can be adapt to fit this engine easily !

mtmniles 03-24-2003 02:47 PM

Thanks for the help Air, I didn't think about going with the 200 tranny. I have been looking online about the process with putting one in, I have a Ram Air III, modified and chevy 12 bolt with 3.73, so I think that the 200 would be a good bet. Thing that scares me is with the TV cable, is this a hard thing to make sure that it is set up correctly?? Thanks for the advise again.

bigwildgrin 03-24-2003 05:08 PM

the 200 is weak weak weak. the best thing you could do would be to put in a powerglide. they are more efficient than three or four speeds, are considerably lighter and have the exact dimensions as the 350. adaptors are readily availible to mount them to BOP engines, but don't confuse a true poweglide with the mushy BOP two speeds of the '60's.

airworld2 03-24-2003 05:44 PM

many grand national buick run 200 r4 transmission with great results, I personaly ran one behind 455 grand sport stage 1 with no trouble great top end compare to 400 transmission, but transmssion repair is what I do and for the last post power glide transmission did have a muticase but its real hard to find that case any more the 3oo super turbine that came out behind buick, olds and pont was basic the same didnt have the guts in the gear train but works the same.cable is not as hard to set up as you might think!

[ March 24, 2003: Message edited by: airworld2 ]</p>

bigwildgrin 03-24-2003 06:15 PM

I must recant; I am not familiar enough with the 200r4 to call it weak. I had an Olds with a 200r4 that was just a grocery getter and I went through two transmissions before scraping the car. I never put one behind a hot rod engine because of my experience, but maybe I simply had bad luck. but I'm a hardcore fan of the powerglide, and I don't know why anyone would use anything else... :D

Chopt 48 01-24-2006 12:40 AM

While a highly modified glide might be great for certain drag applications I can't see it being stuffed in a street driven car for daily driving in this age and time. I am in the middle of swapping a turbo 400 into my 71 GMC 3/4 in place of the 350 that decided that it didn't want to in any gear right in the middle of the intersection. Two Major deciding factors. I tow with the truck and had the 400 and know that it is a good one. I think my tape measure tells me that the short shaft 400 is 1-1/2 inches longer than the 350 but don't take my word for it.
Your biggest challenge would be having the driveshaft shortened or finding one the correct length, Or spending the bucks and having a new one made.
With the 3:73 gears I would opt for a built overdrive and enjoy the best of both worlds.

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