Swapping to 454.. comes with THM400. Good swap?

[Darkrider]

Basically the early (87–90) TBI trucks were mark IV carved motors and yes, they used a spread bore intake and adapter. I'm not sure but I do believe they had an off specific oil pan.

Sent from my TBI 454 powered android device.

So basically i can use a 454 from 1970 up to 1990 as long as i use the GMT400 specific oil pan or one that will clear the diff. Now i remember you had to search for specific brackets for yours. was that for the AC or something else? Just wondering what accessory brackets i can use from the 350 in my truck currently.

 

[AirmanSkee]

I will look into it more, as I am still insure on the specifics of the motor. I am getting spics and videos if it soon and also a casting number to check. Of anything I will just end up getting the wheels/tires from him without the 454 and scrap the idea til I find a newer 454. Thanks for the no BS answer Dave. That's exactly what I was looking for.

 

[88GMCtruck]

So basically i can use a 454 from 1970 up to 1990 as long as i use the GMT400 specific oil pan or one that will clear the diff. Now i remember you had to search for specific brackets for yours. was that for the AC or something else? Just wondering what accessory brackets i can use from the 350 in my truck currently.

Pretty much. I used a set of aftermarket brackets that adapt the 90-95 aluminum accessory brackets to a big block. The 88-89 steel ones (that you have now) won't work with that setup. All the TBI 454 brackets are steel and are hard to find if you don't have the ones you need. My motor didn't have an AC bracket so the adapters to use the small block aluminum stuff (that was plentiful and looks great) was an easy fix.

I will look into it more, as I am still insure on the specifics of the motor. I am getting spics and videos if it soon and also a casting number to check. Of anything I will just end up getting the wheels/tires from him without the 454 and scrap the idea til I find a newer 454. Thanks for the no BS answer Dave. That's exactly what I was looking for.

No problem.

 

[AirmanSkee]

Think I am just going to buy just te tires and hold off til I find a Vortec 454 as you said. Thanks for the advise.

 

[Darkrider]

Pretty much. I used a set of aftermarket brackets that adapt the 90-95 aluminum accessory brackets to a big block. The 88-89 steel ones (that you have now) won't work with that setup. All the TBI 454 brackets are steel and are hard to find if you don't have the ones you need. My motor didn't have an AC bracket so the adapters to use the small block aluminum stuff (that was plentiful and looks great) was an easy fix.

I should clarify something here about my truck. It was originally a 454 but sometime along its life it had a 350 swapped into it and i believe its got the aluminum brackets on it. I will double check sometime this week though.

Heres a pic of the engine thats in the truck now...it looks like the bracket between the alt and power steering pump is aluminum

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sorry about the 'jack Skee

 

[88GMCtruck]

Yup you have the aluminum ones, just need the adapter brackets.

Sent from my TBI 454 powered android device.

 

[Darkrider]

Yup you have the aluminum ones, just need the adapter brackets.

Sent from my TBI 454 powered android device.

Awesome! So basically the only thing left to figure out is the oil pan situation. I should see if there are any 454 powered GMT400s in the yard here..though i think most are 350s...I know that on the early 6.2 Diesels that had the two piece main seal on them GM made a special oil pan to keep using those motors in the early GMT400 4wds ( i think they only used those for 88 and 89) so im wondering if there is a 4wd specific pan for the 87-90 mark IV engines.

 

[88GMCtruck]

There would be a IFS specific 88-90 4wd pan. And the 6.2L Diesels were in GMT400s up till 1993.

 

[Darkrider]

There would be a IFS specific 88-90 4wd pan. And the 6.2L Diesels were in GMT400s up till 1993.

Had a feeling you were going to say that. From what i was reading it was around '89 or 90 that GM switched from a 2 piece seal on the 6.2 to the same style 1 piece seal as used on the 6.5 when it came out.

 

[454ss]

ive never had to change oil pans on any bbc ive swapped into a gmt400. from 70s 402 to new 502.