Queston on my 1978 GMC

[jimi]

I am swapping out my 400small block for a 454 big block, and Im have a 1/2 ton. will the front and rear end hold up? 10 bolt front, and 12 bolt rear? Im am going to offroad this truck ( Diamond trales ). 37 or 39 tires. still need to put alot of work into it.

 

[max 02]

Welcome.

I foresee you spending more time posting on 3/4 ton swaps in your future.

Sure it will work...if you take it easy. But just when you start having fun Sh!t will start to break.

 

[82355]

That's a loaded question. I have had 454's that made less horsepower than some 350's. With that size of tire you are going to want to upgrade to 3/4 ton axles and probably a Dana 60 in the front eventually.

Martin

 

[454Sub]

If you nurse it, sure. If you step on it, not for long.

 

[diesel4me]

When I swapped a 400 SB into my '77 K2500 that formerly had a '74 454 from a Chevelle in it,I felt the 400 SB was more powerful and at least as torquey as the smog era 454 was...it was a bit lighter weight overall too,which didn't hurt any too...depending on the year and build of the 454 your using ,it could put the axles under more stress,but overall ,for daily driving uses,I doub't you'd have many problems with the axles...but doing burnouts with those big tires though,might be cause for regrets!..my truck had a 14 bolt SF in the rear and the usual 10 bolt Dana 44 up front,I plowed that truck to death for a good 10 years and never had any diff troubles...didn't baby the truck--but I didn't whale on it either,I used some common sense..