Author Topic: 1980 Trans Am Engine Swap. 301 to 400  (Read 4849 times)

Squamish Sasquatch

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1980 Trans Am Engine Swap. 301 to 400
« on: March 07, 2011, 03:35:40 PM »
I just picked up a 75 Pontiac 400. The Numbers I have found on it are.
-0230162 YT on front passenger side of block
-481988 on rear passenger side of block
-5C on heads

It has an Edelbrock P4B intake and no carb yet.

I am going to swap the Pontiac 301 (non-turbo) out of my 1980 Trans Am (3.08 gears) for the Pontiac 400.  So now the questions.

First, will the transmission from my 301 (TH350 I beleive) bolt right to the Pontiac 400? The guy I bought the 400 from said it was bolted to a TH400.

How easy of an engine swap is this. Can I use most of the aux. componants from my 301? Any info would be great.

What are the best carb and headers to get for this set up? I am not a big fan of the QJ. The less vacum hoses I can deal with the better.

Thanks for any help.
1980 Trans Am, Pontiac 400, 3.08 Posi

koury73

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Re: 1980 Trans Am Engine Swap. 301 to 400
« Reply #1 on: March 07, 2011, 03:57:00 PM »
externally the 301 and 400 are the same so you can use all of your valve covers, pulleys, timing cover, valley pan, etc and it will bolt in just as the 301 did.  The th350 will bolt right up and will also fit in the same manner as it did witht the 301.  For carb help, I like QJ's personally.  An option could be just to block off all of the vacuum ports you aren't going to use.  As far as intakes, the edelbrock  performer is the only one that I know of that you can use and still retain all of the original shaker mounting items but you will not gain any performance with this intake as opposed to the original intake.  Carburetor choices also have to be made wisely if you plan on using the stock shaker setup.
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bluethunder

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Re: 1980 Trans Am Engine Swap. 301 to 400
« Reply #2 on: March 07, 2011, 07:05:40 PM »
The 301 was a short deck motor, so it wasn't the same as the 327/350/400.

I'm not sure what is compatible between the 2, but I know the bracketry was different between my p350 and the 301.
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koury73

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Re: 1980 Trans Am Engine Swap. 301 to 400
« Reply #3 on: March 08, 2011, 08:37:36 AM »
oh shoot thats right, i had 350 on the brain.  Sorry im not sure either.  I've never had a 301 so my rant up there is no good lol
good. . bad. . . I'm the guy with the gun.


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72blackbird

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Re: 1980 Trans Am Engine Swap. 301 to 400
« Reply #4 on: March 08, 2011, 11:17:29 AM »
You could use the TH-350- with a good rebuild they can more than withstand the torque of a 400 or 455. but as far as using any of the components off the 301 other than the power steering pump and alternator, you're better off getting accessory brackets that fit the 326-455 Pontiac V-8 family. I believe the timing cover will physically fit, but if your 301 has the smaller- hub-style balancer the bolt-on timing tab will not work with the larger 6.75" harmonic balancer. Get a timing cover w/ a cast-in timing tab.

the 75 400 you have is a good solid block and a good candidate for a stroker build if you plan to do so in the future. The 5c heads are okay , about 96-98ccs for 7.8-8:1 on a 400.
1977 SE T/A (sold :( )
1974 455 T/A (sold :( )
1972 Esprit restomod
1976 T/A restomod
1975 Formula 400 4-speed

Squamish Sasquatch

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Re: 1980 Trans Am Engine Swap. 301 to 400
« Reply #5 on: March 08, 2011, 01:24:13 PM »
Thanks guys,

The 400 block I picked up is a long block so I don't need to take too much off the 301 besides the steering pump, alternator, distributor and a few other things (which maybe someone could mention haha). Should the mounts be the same?

So we're all agreeing that the tranny from my 301 will bolt up to the 400 with no problems, it will be rebuilt when removed.

Yeah I was so relieved when I found out it was the 988 block and not the other one.

Does anyone know the most simple and effective carb to use? I'm not a hotrodder by any means so stock or show is thrown out. I have the Edelbrock P4B intake (i beleive the square holly pattern). What carb will still make my shaker somewhat usable?
1980 Trans Am, Pontiac 400, 3.08 Posi

72blackbird

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Re: 1980 Trans Am Engine Swap. 301 to 400
« Reply #6 on: March 09, 2011, 11:23:16 AM »
I'm not sure about the Edelbrock P4B, but the Performer is the same height as the factory intake and will work w/ the stock shaker assembly. I t does have a spreadbore base to work w/ the Q-jet, but a simple squarebore adapter plate will allow you to use a squarebore carb. I run a Holley 3310 750 vac. sec.w/ a secondary metering block- pretty easy to to tune and maintain, but w/o a modified shaker base or WFO base it won't work w/ the shaker set up.
1977 SE T/A (sold :( )
1974 455 T/A (sold :( )
1972 Esprit restomod
1976 T/A restomod
1975 Formula 400 4-speed

BigJer

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Re: 1980 Trans Am Engine Swap. 301 to 400
« Reply #7 on: March 09, 2011, 11:43:39 AM »
I did some research on the P4B and when compared to stock or the Performer, it is a drop in performance. I say try to find a used Performer-lighter weight,better performance and no shaker fitment issues.

Re: 1980 Trans Am Engine Swap. 301 to 400
« Reply #7 on: March 09, 2011, 11:43:39 AM »
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