402 to 454 swap - The 1947 - Present Chevrolet & GMC Truck Message Board Network

So.Cal.Super · 01-22-2011, 05:31 PM

Hey Everyone.
So the 72 has been acting up, after replacing sending units and tuning the carb I was still having problems with lack of power. I put a vacuum gauge on the engine and the needle bounces around more then my speedo when i'm running late. It seems my valve springs are worn out and I know the P/O only had seals and rings replaced in the engine when he owned it and no other work has been done but my upgardes in 20 years.

So rather then pull out the 402 and refesh and build it up I am thinking about going with a 454 the build will run me the same with more options availiable.

Here are my questions and thanks already to Nigel (Eightbanger) for already answering a bunch. I know the Motor mounts I have will line up and work, and the power steering and alternator will mount on the drivers side where they are now.

What about the A/C ? will the brackets I have on the 402 mount up to the 454 on the passenger side or is this going to be a problem?

Any more info from anyone that has done this swap or any tips or tricks are much appreceated.

Thanks!

sameyrasmea72 · 01-22-2011, 06:02 PM

As far as I know everything will be exactly the same. I think just looking at it you can't even tell the difference. The only exception would be the harmonic balancer. I am pretty sure a 454 has a different size one, but that will make no difference except for looks.

You have to use the 454 balancer on the 454.

LONGHAIR · 01-22-2011, 06:03 PM

Everything is the same with 2 huge exceptions.....The harmonic balancer and the flywheel/flexplate cannot be swapped. The 454 is externally balanced and these parts are counter-weighted to compensate for it.

So.Cal.Super · 01-23-2011, 12:38 PM

good info, thanks.

I just thought of a few things like, Will my headers I have now work? I know they are oval port Dougs headers and is it any Gen IV or do I need to avoid newer ones for some reason?

Thanks

Tx Firefighter · 01-23-2011, 02:53 PM

Like Longhair said, it will all change over. Just make sure and use a 454 specific harmonic balancer and flywheel. Your brackets, accessories, exhaust, mounts, distributor, all of that will swap right over.

**special-K** · 01-23-2011, 06:10 PM

All the same except the balancer/flywheel. I swapped an LS6 into a '70 big block truck and made it look like a stock 396/402,except for the Edelbrock intake I painted Chevy Orange.

So.Cal.Super · 01-23-2011, 08:01 PM

Thanks for all the good info. now its just planning and budgeting....Yay!!!

01-22-2011, 05:31 PM	#1
So.Cal.Super It'll Buff Out! Join Date: Apr 2007 Location: San Diego Posts: 603	402 to 454 swap Hey Everyone. So the 72 has been acting up, after replacing sending units and tuning the carb I was still having problems with lack of power. I put a vacuum gauge on the engine and the needle bounces around more then my speedo when i'm running late. It seems my valve springs are worn out and I know the P/O only had seals and rings replaced in the engine when he owned it and no other work has been done but my upgardes in 20 years. So rather then pull out the 402 and refesh and build it up I am thinking about going with a 454 the build will run me the same with more options availiable. Here are my questions and thanks already to Nigel (Eightbanger) for already answering a bunch. I know the Motor mounts I have will line up and work, and the power steering and alternator will mount on the drivers side where they are now. What about the A/C ? will the brackets I have on the 402 mount up to the 454 on the passenger side or is this going to be a problem? Any more info from anyone that has done this swap or any tips or tricks are much appreceated. Thanks! __________________ "Instructions are just another mans opinion" Become a Supporting Member http://67-72chevytrucks.com/vboard/payments.php Man Card Rules http://67-72chevytrucks.com/vboard/s...d.php?t=634550 72 Chevy Cheyenne Super 400 LWB

01-22-2011, 06:02 PM	#2
sameyrasmea72 Senior Member Join Date: Aug 2003 Location: Lubbock, Texas Posts: 2,443	Re: 402 to 454 swap As far as I know everything will be exactly the same. I think just looking at it you can't even tell the difference. The only exception would be the harmonic balancer. I am pretty sure a 454 has a different size one, but that will make no difference except for looks. You have to use the 454 balancer on the 454. __________________ 72 Cheyenne Super 80 Silverado Blazer 2wd Last edited by sameyrasmea72; 01-22-2011 at 06:16 PM.

01-23-2011, 12:38 PM	#4
So.Cal.Super It'll Buff Out! Join Date: Apr 2007 Location: San Diego Posts: 603	Re: 402 to 454 swap good info, thanks. I just thought of a few things like, Will my headers I have now work? I know they are oval port Dougs headers and is it any Gen IV or do I need to avoid newer ones for some reason? Thanks __________________ "Instructions are just another mans opinion" Become a Supporting Member http://67-72chevytrucks.com/vboard/payments.php Man Card Rules http://67-72chevytrucks.com/vboard/s...d.php?t=634550 72 Chevy Cheyenne Super 400 LWB

01-23-2011, 02:53 PM	#5
Tx Firefighter Watch out for your cornhole ! Join Date: Jun 2003 Location: Azle, Texas Posts: 14,162	Re: 402 to 454 swap Like Longhair said, it will all change over. Just make sure and use a 454 specific harmonic balancer and flywheel. Your brackets, accessories, exhaust, mounts, distributor, all of that will swap right over. __________________ I'm on the Instagram- @Gearhead_Kevin

01-23-2011, 06:10 PM	#6
special-K Special Order Join Date: Nov 2004 Location: Mt Airy, MD Posts: 85,851	Re: 402 to 454 swap All the same except the balancer/flywheel. I swapped an LS6 into a '70 big block truck and made it look like a stock 396/402,except for the Edelbrock intake I painted Chevy Orange. __________________ "BUILDING A BETTER WAY TO SERVE THE USA"......67/72......"The New Breed" GMC '67 C1500 Wideside Super Custom SWB: 327/M22/3.42 posi.........."The '67" (project) GMC '72 K2500 Wideside Sierra Custom Camper: 350/TH350/4.10 Power-Lok..."The '72" (rolling) Tim "Don't call me a redneck. I'm a rough cut country gentleman" R.I.P. ~ East Side Low Life ~ El Jay ~ 72BLUZ ~ Fasteddie69 ~ Ron586 ~ 67ChevyRedneck ~ Grumpy Old Man ~

01-23-2011, 08:01 PM	#7
So.Cal.Super It'll Buff Out! Join Date: Apr 2007 Location: San Diego Posts: 603	Re: 402 to 454 swap Thanks for all the good info. now its just planning and budgeting....Yay!!! __________________ "Instructions are just another mans opinion" Become a Supporting Member http://67-72chevytrucks.com/vboard/payments.php Man Card Rules http://67-72chevytrucks.com/vboard/s...d.php?t=634550 72 Chevy Cheyenne Super 400 LWB



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