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400sbc with th350 tranny

PostPosted: Wed Apr 13, 2016 1:30 am
by mirage_brat
Will a th350 tranny hold up to a mildy built 400sbc if so what would I need to use for a flexplate

Re: 400sbc with th350 tranny

PostPosted: Wed Apr 13, 2016 3:19 am
by Smiley
A 400 smallblock (and 383) uses a unique external balance flywheel and harmonic balancer
400 flywheels are the larger 168 tooth size so a mini starter my be in order also.
If the TH350 is in good condition it should hold up to a mild 400. I would suggest a rebuild (new clutches and seals) as well as a shift kit.
If you run a higher than stock stall torque converter add an external trans fliud cooler.

Re: 400sbc with th350 tranny

PostPosted: Wed Apr 13, 2016 6:13 am
by mirage_brat
i already had the tranny gone through with a shift kit, manual valve body, and a 2900 stall converter plus i have a mildly built 350 right now

Re: 400sbc with th350 tranny

PostPosted: Wed Apr 13, 2016 7:19 am
by spencerforhire
You used to be able to buy a counterweight that bolted on the crank under the neutral balance 153 tooth flexplate. There's one in my old 76 GT with the 400, but I just searched the Summit website and couldn't find a listing.

Re: 400sbc with th350 tranny

PostPosted: Wed Apr 13, 2016 10:28 am
by Kenova
Smiley wrote:A 400 smallblock (and 383) uses a unique external balance flywheel and harmonic balancer....


The correct damper and flywheel are an absolute must have. (Ask me how I know :bang: )
Without the proper damper and flywheel you are in for a world of hurt (and a broken trans housing).

Ken

Re: 400sbc with th350 tranny

PostPosted: Wed Apr 13, 2016 3:47 pm
by Monza Harry
I remember those Spencer So I did a quick search, and at least found a few pic's, here is the whole search outcome. Harry https://ca.search.yahoo.com/search;_ylt ... orcl_hpset and the piece: http://shop.whiteperformance.com/400-38 ... PS-400.htm and I am sure that Speedway sells this too: http://www.speedwaymotors.com/1955-85-S ... ,3262.html and check out the price hard to go wrong there!

Re: 400sbc with th350 tranny

PostPosted: Wed Apr 13, 2016 5:19 pm
by spencerforhire
I bought one from Speedway 25+ years ago, but assumed (wrongly) that they would be available at Summit. Didn't even think to look elsewhere.

Re: 400sbc with th350 tranny

PostPosted: Sun Aug 14, 2016 4:35 pm
by 75Monzta
Hey Spence, just make sure those Saturn fuse blocks are good. Replaced literally a couple hundred of them in my career as a tech. :-)

Re: 400sbc with th350 tranny

PostPosted: Sun Aug 14, 2016 5:51 pm
by Monza Harry
So Spencer do you still have that "FLEET" of 13 cars? or is it time to update the signature? :pook: Harry P.S. I am down to 3 and 1/4 if you consider the black 1980 a quarter from almost 8, [the extra Monza was more complete before] house cleaning had to happen!

Re: 400sbc with th350 tranny

PostPosted: Sun Aug 14, 2016 7:11 pm
by chevyart
if someone else built the motor AND maybe they used an aftermarket crank, it could have been built with the crank internally balanced , therefore enaBLING YOU TO USE REGULAR AFTERMARKET HARMONIC BALANCER AND REGULAR 168 TOOTH FLEXPLATE. IF it is A stock GM CRANK, ITS MOst likely AN EXTERNALY BALANCED ENGINE, THEN YOU NEED TO USE THE PARTS LIKE SPENCE AND THE OTHER GUYS TALKED ABOUT. ART

Re: 400sbc with th350 tranny

PostPosted: Sun Aug 14, 2016 8:59 pm
by spencerforhire
I hate to hijack this thread like this, but Monza Harry asked me to update my signature so I did. :shock:
At least they're not ALL in my yard. 5 of the Saturns reside elsewhere; My Daughter lives in ST. John's Newfoundland, both my sons live in the city, and 2 of the parts cars are lodged at a friend's place a mile down the road.
All the rest are used in a giant size game of Tetris every time I need to get a vehicle in or out of the garage. Or the hauler out for a weekend of racing.