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73-87 Chevy _ GMC Trucks => Engine/Drivetrain => Topic started by: 85cehvy4x4 on January 20, 2009, 08:40:52 am

Title: 454/4speed swap
Post by: 85cehvy4x4 on January 20, 2009, 08:40:52 am

Hello, My buddy wants to trade me a 454 motor for an old peice of junk truck i have. My question is, it would be going into my 85 half ton that currently has a 350 with an SM465 4 speed? Will the big block drop right in with no modifactions? He told me that my bellhousing will bolt right up to it, but im not sure. He also said the motor mounts will work to. The motor only needs a carb and a set of headers to run, im just wondering about the interchangeability. Thanks for any info ya'll can provide. I tried the search button but couldnt find anything helpful.

Title: Re: 454/4speed swap
Post by: zieg85 on January 20, 2009, 08:48:22 am

The swap is pretty straight forward.  Yes the bell housing and motor mounts are the same.  The power steering bracket is going to be different.  Not sure if the flywheel from a 350 will go with the 454, some are externally balanced.

Title: Re: 454/4speed swap
Post by: ccz145a on January 20, 2009, 09:16:14 am

He is not leading you astray, all those things will bolt right up.

But, the following come to mind...

You will need brackets for all your accessories: alt, ps, a/c, etc...

The 454 is externally ballanced, so you will need a new flywheel.

The big block is about 200lbs heavier, if you want the same ride height you will need the big block front springs, if not then get your front end realigned and reaim your headlights

Might need to upgrade the radiator.

Title: Re: 454/4speed swap
Post by: zieg85 on January 20, 2009, 09:27:03 am

Thanks for the correction, it has been a while since I made the swap.

Title: Re: 454/4speed swap
Post by: Captkaos on January 20, 2009, 11:33:42 am

I used my SBC power steering setup on my BBC.

Title: Re: 454/4speed swap
Post by: 85cehvy4x4 on January 20, 2009, 05:32:56 pm

Brackets and pullies and stuff wouldnt be a problem becasue there all there. I'm wondering about the transmission. It came out of a 79 Jimmy 4x4 with a 4 speed, my truck is an 85 with a 4 speed, 4 wheel drive. My dad was wondering about the input shaft for the transmission. Will mine work? I'm not sure of the spline count, I've never had my tranny down before.

Title: Re: 454/4speed swap
Post by: Captkaos on January 20, 2009, 05:38:25 pm

If you are just getting the motor, that transmission doesn't matter, but the 79 4 speed and the 84 4 speed should have the same 10 spline input. The trans will bolt to any V8 Chevy.
Spline count is determined by the transmission, not the motor connected to it.  You order the spline count with (example) 11" clutch with 10 spline. 

Title: Re: 454/4speed swap
Post by: 85cehvy4x4 on January 21, 2009, 08:31:16 am

Alright cool, thanks for all your help.

Title: Re: 454/4speed swap
Post by: eventhorizon66 on January 27, 2009, 02:04:05 pm

As far as accessories go, I thought you might want to know about these (http://www.kwikperf.com/bbc_serp_kit.html).