Author Topic: 1980 Trans Am 301 Swap to 400 (Motor Mounts )  (Read 3218 times)

d_hache

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1980 Trans Am 301 Swap to 400 (Motor Mounts )
« on: April 05, 2021, 09:44:33 AM »
Hey guys, i am swapping my 301 in my 1980 Trans Am with a Pontiac 400 that came out of an 1973 Grand Prix.
Can i re-use the same motor mounts and brackets from the 301?
Let me know
TY

5th T/A

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Re: 1980 Trans Am 301 Swap to 400 (Motor Mounts )
« Reply #1 on: April 05, 2021, 07:53:37 PM »
Yes,

I just did the same, swapped the original 301 in my 1980 with a 461 stroker using the original mounts on the subframe and brackets that bolt to the block. I believe my 400 came out of either a 1978 or 1979 TA. I am pretty sure any Pontiac V8 1970-1981 will use the same mounts.
1980 T/A with a Pontiac 461

Gone but not forgotten;
1973 T/A 455
1975 T/A 400
1978 T/A W72
1982 T/A cross fire injected

Two wheel toys;
2014 Harley Ultra Classic Limited
2013 Honda CB1100
2010 Yamaha Vmax
1982 Yamaha Seca 750

gennaros ta

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Re: 1980 Trans Am 301 Swap to 400 (Motor Mounts )
« Reply #2 on: April 07, 2021, 06:09:44 PM »
They will work . I did the same swap but with a 69 400. I had to buy special brackets to make it work on 69 block  and still was able to use the 301 engine brackets and motor mounts.

tiggershark

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Re: 1980 Trans Am 301 Swap to 400 (Motor Mounts )
« Reply #3 on: April 09, 2021, 08:41:29 AM »
Go with new ones. Cheap enough and the rubber will be in much better shape than original

d_hache

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Re: 1980 Trans Am 301 Swap to 400 (Motor Mounts )
« Reply #4 on: April 21, 2021, 12:24:31 PM »
Thanks for the info guys, looks like they will work but maybe some new ones if the old ones are not in the best of shape.
TY

Re: 1980 Trans Am 301 Swap to 400 (Motor Mounts )
« Reply #4 on: April 21, 2021, 12:24:31 PM »

tiggershark

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Re: 1980 Trans Am 301 Swap to 400 (Motor Mounts )
« Reply #5 on: April 25, 2021, 11:16:56 AM »
Look for cracks in the rubber, if you find any ( which you will ) new ones wont break the bank at all. New mounting bolts/nuts as well

Seven

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Re: 1980 Trans Am 301 Swap to 400 (Motor Mounts )
« Reply #6 on: April 28, 2021, 01:23:52 PM »
I'll be making the similar swap later this spring into a 1979 301 4 speed car. 

What else can be used from the 301?  Will the starter work on a 481988 casting 400?  I understand the power steering and alternator brackets won't work, but what about the water pump and crank pulleys and the power steering pump itself?
LT4 Firehawk
1979 Y84 T-top Delete
1972 Esprit 455 HO

tajoe

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Re: 1980 Trans Am 301 Swap to 400 (Motor Mounts )
« Reply #7 on: April 28, 2021, 03:11:36 PM »
Not sure how much I can contribute here, but Joe "use-ta" run the 301 column on this site, so maybe you can find more accurate info there. I have an 80 TTA motor on my eng. stand as we speak, and I tried to "eyeball" it for your question. but it's tough to do, seeing 1/2 my accessories are missing. The timing cover looks identical to the traditional one, but can't say for sure. Starter is also gone, but if you find out your frt stuff doesn't work, and you want some extra cash, I'ld be interested in purchasing some of it.
"You can sell an old man a young mans car,
but you can't sell a young man an old mans car"
                                       Bunkie Knudsen
<

5th T/A

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Re: 1980 Trans Am 301 Swap to 400 (Motor Mounts )
« Reply #8 on: April 28, 2021, 07:50:51 PM »
Seven,

For my 301 to 461 swap I used the power steering and alternator brackets from a 1974 455. I was able to use the original 1980 power steering pump with the 1974 alternator and power steering brackets.

My 301 came with an air pump, so the alternator and air pump belt does not ride on the water pump. There is only a single pulley on the water pump and it is driven by the power steering belt. The 455 water pump has two pulleys, one driven by the power steering pump and the other by the alternator belt.

The 301 crankshaft pulleys are 8" in diameter for the power steering and alternator belts, 7 1/4 " for the AC compressor. The 455 uses 7 1/4" crankshaft pulleys for all three belts.

I am very confident that Pontiac 350's, 400's and 455's used the same alternator and power steering brackets.

I can't answer as to if a 301 starter will fit on a 400 block. If I had to guess I would say it will. But, the 301 starter is a much lighter weight unit and probably won't have the necessary torque to turn over a 400. I have my original 301 starter and the starter that came with my 455. The 301 is smaller and weighs considerably less. The 301 starter is direct drive, not a gear reduction like modern high torque after market starter.

You did not mention the AC compressor brackets. Most of those are different as well on the 301.
1980 T/A with a Pontiac 461

Gone but not forgotten;
1973 T/A 455
1975 T/A 400
1978 T/A W72
1982 T/A cross fire injected

Two wheel toys;
2014 Harley Ultra Classic Limited
2013 Honda CB1100
2010 Yamaha Vmax
1982 Yamaha Seca 750

Seven

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Re: 1980 Trans Am 301 Swap to 400 (Motor Mounts )
« Reply #9 on: April 28, 2021, 10:07:45 PM »
5th T/A, thank you, that's exactly the information I'm looking for.  I'm down to finding the correct 400 pulleys and an appropriate starter.

I found a company called AMK Products that has the correct bolts, spacers and washers to mount the power steering pump and alternator.

Would you know if the 301 shaker will work with a 400 shaker base, or is the shaker itself unique to the 301?

Seven
LT4 Firehawk
1979 Y84 T-top Delete
1972 Esprit 455 HO

5th T/A

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Re: 1980 Trans Am 301 Swap to 400 (Motor Mounts )
« Reply #10 on: April 30, 2021, 05:27:32 PM »
Seven,

The 301 shaker will work on a 400 base. You will also need a 400 shaker air cleaner assembly, as the 301 air cleaner is much smaller. Sine I am using a taller intake than the stock Pontiac I had to purchase an after market drop base air cleaner.

I just switched mine over today. You will have to carefully drill out rivets and separate your original base from the shaker. Mine was also glued together, I used a drywall knife to split the two parts. I purchased my 400 base from Classic industries and used pan head screws with nylon locking nuts to tie the new base to my original shaker.

New 400 base on the right.

IMG_8013 by Lawrence Alexander, on Flickr

New 400 base bolted to original 301 shaker scoop.

IMG_8016 by Lawrence Alexander, on Flickr


1980 T/A with a Pontiac 461

Gone but not forgotten;
1973 T/A 455
1975 T/A 400
1978 T/A W72
1982 T/A cross fire injected

Two wheel toys;
2014 Harley Ultra Classic Limited
2013 Honda CB1100
2010 Yamaha Vmax
1982 Yamaha Seca 750

Seven

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  • Posts: 78
Re: 1980 Trans Am 301 Swap to 400 (Motor Mounts )
« Reply #11 on: May 11, 2021, 03:31:18 PM »
5th T/A,

Nice work!  I've got my shaker base on order.

When you dropped your 400 in, did you already have your exhaust manifolds, brackets and pulleys installed or did you mount everything after the engine
 was in the mounts?
LT4 Firehawk
1979 Y84 T-top Delete
1972 Esprit 455 HO

5th T/A

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Re: 1980 Trans Am 301 Swap to 400 (Motor Mounts )
« Reply #12 on: May 11, 2021, 03:54:26 PM »
Seven,

My exhaust manifolds are Ram Air III type, came from Ram Air Restorations. I bolted them on before dropping in the engine. I think it would be a lot harder to install the manifolds with the engine in place. But years ago I know I did it that way as well. I installed the alternator/ power steering brackets and AC brackets all after the engine was installed. But it was just the subframe, the core support, and fenders were off the car at the time.
1980 T/A with a Pontiac 461

Gone but not forgotten;
1973 T/A 455
1975 T/A 400
1978 T/A W72
1982 T/A cross fire injected

Two wheel toys;
2014 Harley Ultra Classic Limited
2013 Honda CB1100
2010 Yamaha Vmax
1982 Yamaha Seca 750

Re: 1980 Trans Am 301 Swap to 400 (Motor Mounts )
« Reply #12 on: May 11, 2021, 03:54:26 PM »
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