1980 Cutlass mods

[classic_man]

I just got a 1980 Cutlass supreme brougham with a 4.3 260 v8...not sure what the trans is turbo 350? looking to pull motor and replace with a Olds 350 or 403. What do you think? can I upgrade the turbo 350 is that is whats on there?

 

[mebe007]

many things can be done to upgrade the turbo 350. spags, elements, pumps, valve bodies. remove the cushion steels. different frictions, new band etc. you can easily make the th350 as strong or stronger than a 400 and it is supposedly already more efficient with better gear ratios and lighter,

 

[outsider_27]

Chances are your transmission is the weaker, but widely installed TH200. It may have been swapped earlier in it's life to a TH350, but I would not expect that. The one I had in mine was rebuilt. If you are going to swap engines, check that first so you don't put a higher HP engine in and then blow the transmission.

 

[silent_orchestra]

Easy way to tell...Look under your car.... If it's a TH 200 the trans pan should say metric... If not ya probably have a TH350....

And as far as building a 350 you can build the crap out of 'em.... And it would be a great trans for a 350 or a 403...

If you were going with a 400/425/455 I'd recomend a 400.... A switch pitch (variable pitch) 400 would be the hot set up. I want to eventually put my 425 and my switch pitch 400 in my '80.... But that little 260 still has alot of life left in her...hell she's only got 67,000 on her.

 

[classic_man]

Thanks, yeah..my cutty has around 66,000 miles. Do you know what the gearing is for 80?

http://www.cardomain.com/ride/3108222

 

[DRIVEN]

Gearing is undoubtedly lame. If you have the RPO code sticker inside the trunk lid look for the axle code. I can't remember when they started doing it (my '79 doesn't have it). If the sticker isn't there you will have to jack up the rear and check it by hand.
G72 2.14
GH2 2.29
GU1 2.41
GM8 2.56
GU2 2.73
GU3 2.93
GU4 3.08
GU5 3.23
GU6 3.42
GU7 2.77
GU8 3.90
GU9 3.91

 

[Blake442]

They started putting the RPO labels under the trunk lid in '84.

 

[silent_orchestra]

If you've got the build sheet it should be on there.... Mines still in the car, just haven't really looked at it to much..

 

[3XBrownCutty]

Build sheet is the best way... I thoughth I had a th350 until I found out it was a th250 from my sheet. th2&350 are almost identical...