I installed a TH350 in my 1994 trans am and I feel as if I lost bottom end.
You think I sould go lower in rear end gear, I have 3.42's right now.
But I really think I lost power putting that in.

 

LT1/LT4 Engine Tech is for engine questions only. Moving...........

 

It's because of the higher 1st gear in the TH350. You can get some gears but then you'll be a HIGH RPM @55+MPH. Your choice.....slower take off....or slower up top.

 

I went from a stock z28 with a 4L60e with a muffler, did a motor swap into a trans am,
added headers to an ORY to a glasspack, 1.6 roller rockers, 2.73 to 3.42, TH350 and a custom cold air intake.

I understand my shift points are different but dang....

 

Many people are disapointed with the results of this swap . Other than goig back to the 4l60e (good idea) you could use a large stall converter to regain the launch you had. but with and addiional trade off of fuel efficency in the bottom. I never have really understood the 4l60e to 350 swap . The trans are so similar and the 350 offer not significant durabiliy over the 4l60e when the trans is correctly built and tuned.

 

Oh, dont get me wrong... I would much rather perfer my 4L60e over a 3spd but I already spent over a GRAND having it rebuilt and then it popped again....
I got a good deal on the TH350 so I went ahead and put it in.....

 

Well i had a buddy have his 4l60e rebuilt... cost him $2600 and i had "good clutches and etc." bunch of crap. It popped on him about 1 month later. He has a lid, "baby cam", smaller than a hot cam, and full exhuast.
Thats it, its hard to trust alot of tranny shops so i just installed a th350 and havent had any problems since....