["79]

ok here go's i want to get rid of the 403 in my 79 t/a and put the pont 400 in. can it be done while retaining the automatic trans and if so what do i need to know to do it thanks for any help

["79]

ok here go's i want to get rid of the 403 in my 79 t/a and put the pont 400 in. can it be done while retaining the automatic trans and if so what do i need to know to do it thanks for any help

[Lemans1]

I have done this swap before and it is actually very easy. You can keep your trans no problem. The frame mounts are the same(as Olds used adapter plates on the block instead). The only things you will have to change are the power steering brackets on the pump and the brackets on the ac compressor(if equipped). Of course a full set of brackets for your pontiac. The only other thing is the fuel lines for the olds are on the pass. side while the fuel pump for the pont. is on the drivers side. I used an electric pump so I had no problem with that but I am sure it is an easy fix. Oh.....one more thing....your exhaust will not fit....the Olds manifolds and Pont. dont dump in the same place. So headers and duals at the same time is a good idea. Hope that gives you some idea of what you are in for....really no big deal. [img]smile.gif[/img]

[Brian Baker]

I've done this swap as well (although with a 455, same difference as a 400).

You'll need a shaker assembly for the Pontiac as well. If you put the Olds shaker on a Pontiac it will sit back too far and not allow the hood to be closed. Changing just the scoop and not the lower pan will not help either, you'll need a scoop and lower filter pan from a Pontiac (and not a 301, gotta' be from a 400 or 455 T/A).

If you have any other specific questions about the swap, drop me an e-mail.

[Lemans1]

Oooops...right..I forgot about that. I was thinking the engine in and forgot all about the shaker. Another good example as to why this board is so good...lots of people and experience.

["79]

ok sounds like this might be a good idea after all i wanted to get rid of the 403 because of the week maines on it i will definetely do this swap i am suprised to here that the 400 will bolt up to the th350 trans any info on the 400 such as performance, you know such as how stong is the block ? can i build this thing into a competitive motor i,d like to eventually turn it into a 10.5:1 compression engine can i do this with the 400 because i really don,t know much about this motor all i know is its got to be better than the 403 so many questions so little time more to come thanks

[Brian Baker]

Stick with a block cast in 1970 or later. Pre-70 blocks will require a special mount (which is available) but with post-70 400 blocks being so plentiful it isn't worth the effort.

I'd keep compression below 10:1, preferably 9.0:1-9.5:1 so it will be pump gas friendly.

96, 4X, or 6X heads would be your best bet to keep it pump gas friendly. Look for some 6X-4's (they'll have a 4 stamped on a machined pad just above the spark plug holes).

All Buick, Pontiac, Olds engines have the same bellhousing bolt pattern, which is why any of them would bolt up to your th350.

["79]

thx brian but az emissions laws say i cant use any motor older than the year my car was manufactured where would i be able to get the brackets i need and what would i ask for and also i would like to use edolbrock heads and intake would that work on the 400 as well

[Lemans1]

Screw the emissions laws!! 1st the Edelbrock heads will fit fine as will any Edelbrock intake except the Performer RPM and Victor. They will fit but you will have hood clearance woes. Fabbing/buying a drop base air cleaner will solve that though. As for the emissions though...they say that here in MD too but they dont open the hood and go checking date codes....they wouldnt know what they were looking at anyway. As for brackets....a local junkyard or internet. What you should ask for is simple....every bracket for that year engine. Your best bet is to get a complete engine from a local yard and rebuild it. That way you are sure to get all the brackets you need and more importantly, see what its supposed to look like when its together. Nothing like trying to bolt something together you didnt take apart. Just my opinion...