Asking just for conversation sake.

[Kapdin]

Well i know I have asked the question before. th350 or th400? And i had been convinced on sticking with the th350 but..... once my house and garage are done this fall i want to start on my 77 crew. Which currently has a good solid 400ci th400. While my 79 K20 has a wore out 350ci th350. That th400 just feels so solid and shifting is like brand new and downshifts very smooth while my th350 is very sloppy shifting and doesn't "seem" to like to downshift and does not hold its gear's very long at all comparied to the th400. So just looking for convo on this. Swap the 400ci/th400 into the 79? or is it worth rebuilding the th350 just to stay with it? The crew is getting a 454/4l80e when funds permit.

 

[Jims86]

my vote for the 400

 

[Kapdin]

im thinking so since i shouldn't have to put anything into the 79 and save for the 77. If you remember i was thinking about swapping in the 350tbi i have but the other day it was above 0 i went out and popped the hood on the 91 and.... boy that motor looks tired lol and a whole lot of work and i know nothing of tbi systems. Just seems logical and simple to do the 400/400 swap. Jim you know what a few simple bolt-on's to that 400ci net for hp gain? i know its 180hp stock but can we sqeeze 200ish hp?

 

[Jims86]

im thinking so since i shouldn't have to put anything into the 79 and save for the 77. If you remember i was thinking about swapping in the 350tbi i have but the other day it was above 0 i went out and popped the hood on the 91 and.... boy that motor looks tired lol and a whole lot of work and i know nothing of tbi systems. Just seems logical and simple to do the 400/400 swap. Jim you know what a few simple bolt-on's to that 400ci net for hp gain? i know its 180hp stock but can we sqeeze 200ish hp?

you could probably do that by gasket matching the intake and exhaust ports, and a free flowing exhaust. I dont know much about the 400, but save for te steam ports, it should be similar to any other sbc as far as building for power.

 

[TexasOutlaw87Cummins]

I say 400 also it has over drive to I think

 

[Kapdin]

naw still 3 speed auto. And Jim sounds good, ive ported and polish a bit on powersports so i would deff give it a try.

I've heard the th400/np203 is a power sucking combo tho... any input on that?

 

[Kapdin]

also, is the th400/np205 adaptor the same as the 4l80e/np205?

 

[bucket]

naw still 3 speed auto. And Jim sounds good, ive ported and polish a bit on powersports so i would deff give it a try.

I've heard the th400/np203 is a power sucking combo tho... any input on that?

Probably not any more than a 400/205?

also, is the th400/np205 adaptor the same as the 4l80e/np205?

The later adapter (round pattern) is similar, something needs machined for it to work. It has something to do with how it seals up and I think it needs notched somewhere. Or maybe I'm just talking out of my ass...