How do you make a th350 live?
08-25-2008, 02:39 PM
#1
How do you make a th350 live? I am planning on making 550-650 hp off the crank in my next engine build. I am running a th350. What have any of you guys done to make these transmissions take this kind of abuse without failing? Thanks fellas.
08-25-2008, 03:45 PM
#2
Good clutches, steels, band...Good valvebody. My trans guy recommended a hardened sprag for any sort of nitrous application with 650+rwhp. They're nice transmissions if you build them right...But they're a little more expensive to do over a th400 to get the same power handling capability.
I originally planned on building a th350 for a 700rwhp sbc I was buying, and I would have only had 950 into the trans, that was everything including a reverse manual valvebody minus a brake.
I originally planned on building a th350 for a 700rwhp sbc I was buying, and I would have only had 950 into the trans, that was everything including a reverse manual valvebody minus a brake.
08-25-2008, 04:34 PM
#3
A TH350 doesn't need much at 650 HP.
I install a 36 element sprag and drum assembly that I make. I install the wide bushing in the drum and use a spirolock ring on the sprag retainer.
Dual feed the direct clutches.
At that power level I install Alto Reds in the directs with a 5 count, machining the stock apply piston to fit the extra friction and steel.
I use the Alto reds on the intermediate too.
I don't really feel they are necessary as the TH350 has plenty of hydraulic and clutch capacity with the minor mods I do but I like the smooth intermediates over the grooved ones.
Double up the sun gear bushings and re-drill for lube. Deburr.
Pump clearances are tight, endplay is on the tight end of specs and I try to use a bearing type pump.
Leave the cushion plate in the intermediates.
I have them with automatic VB's at over 650 lb/ft without issue.
The only "fancy" part here is the drum assembly. The rest is basic low cost stuff and good assembly techniques.
I install a 36 element sprag and drum assembly that I make. I install the wide bushing in the drum and use a spirolock ring on the sprag retainer.
Dual feed the direct clutches.
At that power level I install Alto Reds in the directs with a 5 count, machining the stock apply piston to fit the extra friction and steel.
I use the Alto reds on the intermediate too.
I don't really feel they are necessary as the TH350 has plenty of hydraulic and clutch capacity with the minor mods I do but I like the smooth intermediates over the grooved ones.
Double up the sun gear bushings and re-drill for lube. Deburr.
Pump clearances are tight, endplay is on the tight end of specs and I try to use a bearing type pump.
Leave the cushion plate in the intermediates.
I have them with automatic VB's at over 650 lb/ft without issue.
The only "fancy" part here is the drum assembly. The rest is basic low cost stuff and good assembly techniques.
08-26-2008, 05:21 AM
#4
I just need to learn "how" to do these mods you guys have posted. I have never opened one up before so it will be my first time taking one apart. I have a mild sbc right now but will be building a L92'd 6.0 in the future. I have never had any problems with 400ish hp with this tranny.
Im just trying to find out if a tranny rebuild is out of my league or not. I have built engines galore so I don't see a th350 being to bad. Am I right?
Im just trying to find out if a tranny rebuild is out of my league or not. I have built engines galore so I don't see a th350 being to bad. Am I right?
