trans swap = fail on 1/4 times. ideas?

Here is the basic rundown. My cousin decided to do a swap on his 87 c10. Nothing special. van 6.0/ 4l80, etc.. 100% stock. even has stock truck manifolds. after his first time out trying to figure out traction and what not he managed to pull off a 13 flat.

Fast forwad 3 months. he scored a great deal on a th400, with a high dollar valve body and a 3800 stall. and went to the track this past week and his 60 foot was quicker after finally getting it to hook on drag radials but his E.T. dropped to a best of 13.4. What gives?

why did he swap from an 80e to a th400? just for the stall and valve body? i dont know much about the th400s... just a question

Ita already built to hold big power, has a brake on it, a real nice valve body in it, a little less heavy and in the end this is going to be a dedicated track truck so no need for overdrive.

number 1 its hot... number two.. i would think it would gain a little... number three.... the turbo 400 is the exact same gears as the 80E with no HP change other then what the trans swap did free up the heat soaked up.... that sucks.... use the trans brake and Deck it !..

temps where roughly the same. within a few degrees. and i know for a fact his trans temps are lower. he added a deep pan, a big external cooler with a fan and filled it up with a full synthetic.

This is why we are baffled. it doenst add up at all. its doing the adverse of what we expected.

your buddys not shifting as consistant as the computer was in the 80e

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Originally Posted by DBRODS

your buddys not shifting as consistant as the computer was in the 80e

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Come on dude, with all things being equal and all.. He can beat that 80e shifting

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Originally Posted by DBRODS

your buddys not shifting as consistant as the computer was in the 80e

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maybe. he does have a manual valvebody.

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Originally Posted by ducky

come on dude, with all things being equal and all.. He can beat that 80e shifting

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:tvhaha:

am i missing something here?

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Originally Posted by bk_cauley

am i missing something here?

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Inside joke not related to you or any of this situation at all. Sorry, its from some other awesome member on here that tried to validate that point to us. Dont mean to clutter your thread. Carry on lol

so any idea why? seriously...

Throwing this out there..but could the 3800 stall put the 6.0s stock cam out of it's power band?

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Originally Posted by ecld_07

Throwing this out there..but could the 3800 stall put the 6.0s stock cam out of it's power band?

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very likely. but it seems to pull hard all the way up. thats just feel though. no hard core evidence on that.

was he in 3rd when crossing the traps with the 80e or 2nd gear? the 80e has a longer first gear than the th400 right?

the gears in a 80 and 400 are identical... well, except for OD obviously

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Originally Posted by ecld_07

Throwing this out there..but could the 3800 stall put the 6.0s stock cam out of it's power band?

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not likely if anything it should help greatly

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Originally Posted by sprayedenali

the gears in a 80 and 400 are identical... well, except for OD obviously

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i didnt know that, thanks :) hmmmmm looks like i need to look into that swap when i build a track truck

Hey did anyone seem to think that maybe your buddy can't shift as fast and as accurate as the computer controlling the 80E. Since the TH400 is a manual.

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Originally Posted by DBRODS

Hey did anyone seem to think that maybe your buddy can't shift as fast and as accurate as the computer controlling the 80E. Since the TH400 is a manual.

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yeah you did earlier then ducky went to messing with you lol.

i didnt think about that...but that seems like a good reason. was he able to get to the same RPM on every gear like he had his shift set for?