1978 K20 454 Swap

[mattshea125]

Hey looking for someone who has experience with a 454 swap on a K20.

My truck currently has an 8 lug GM 10 Bolt front axle and stops great with the little 350 in it, but I am worried that the front brakes and ball joints aren't going to hold up and perform well with the additional weight of the big block engine.

Also I have driven some diesel trucks that just don't seem to stop for **** and I don't want to experience that with this swap.

Is a front Dana 60 king pin axle ( CUCV style ) worth the money for the increased capacity and how much will I gain in the way of brakes ? They are also getting hard to find. Any info on this would be much appreciated. Thanks

[Zoomad75]

Originally Posted by mattshea125

Hey looking for someone who has experience with a 454 swap on a K20.

My truck currently has an 8 lug GM 10 Bolt front axle and stops great with the little 350 in it, but I am worried that the front brakes and ball joints aren't going to hold up and perform well with the additional weight of the big block engine.

Also I have driven some diesel trucks that just don't seem to stop for **** and I don't want to experience that with this swap.

Is a front Dana 60 king pin axle ( CUCV style ) worth the money for the increased capacity and how much will I gain in the way of brakes ? They are also getting hard to find. Any info on this would be much appreciated. Thanks

The 10 bolt can handle it. If you want the brakes to feel better, swap out the vacuum booster for a hydro-boost setup. That will make the brakes work better and give more solid feel than the vacuum boost setup.

I'll be dropping a 8.1 big block in my K5 and have no plans to upgrade to a 60 unless one dropped in my lap for really cheap. And while it's not my truck I've been around another truck owned by a buddy that ran a big block in his K10 with a D44 for many years without issue. Search for his truck here by his name DirtyLarry. He has been all over Colorado and the Southwest in his truck and only the last few years were with a D60 up front, the rest were with a D44. Oh and when he put the 60 in, he took the D44 and stuffed it under the Big Block in his 89 Suburban. That one is still rolling along strong.

The key to survival is making sure the ball joints are in good shape to start with and the serviceable parts are maintained. Ball joints are not that hard to change out and could be done in your driveway. Going that far will have you inspecting, repacking or replacing your wheel bearings also.

Contrary to what you would read on most forums, a D60 is not an absolute requirement. Factor in tire size and how you plan on using it and you'll know if it's going to survive or not. If you aren't doing any serious rock crawling, locking the front diff or running tires larger than 35" 10 bolt and D44 front axles are just fine.

[b454rat]

I swapped a couple trucks to 454 and never had any braking issues. Couple of them were lifted with 35" tires. And with 10 bolts or Dana 44s. You will be fine...

['63GENIII]

My '63 started out (when I got it) with a 396 and a 6 lug D44 front / 12 bolt rear drum brake combo.

It now has a 7.4, winch bumper, winch sitting on a '73 Dana 44 with the 8 lug disc front axle. Lots of towing and hauling. It does just fine.

Hold onto the little angled zerks and keep the ball joints greased.

Like Zoomad said, if you want the brakes to firm up, get hydro boost but as far as durability the 10 bolt or 44 will hold up fine with a little restraint. Many successful wheelers out there run 'em with few problems.

Now, if your driving style is such that you're popping axles, stubs and U joints, it really won't make a difference if you're running a big block or an inline 6. You're gonna break stuff.

Years ago I demolished a dana 44 front axle in an old '64 f### with a 292. That old front axle made it 30+ years without an issue until it had a numbskull behind the wheel.

With prices for a kingpin at 1500 - 3000 around here, I'll temper my driving style a little and spend the scratch on something else that I really need..... like hydro boost!

[mattshea125]

Thanks for the input. I guess my biggest concern is towing, As I would like to be able to haul smaller equipment around for jobs occasionally. Or a small travel trailer and not stress the wheel bearings and ball joints out. I have a 11.5 GM14 bolt full floater for the rear which should be good. The truck will be running 265/75r16 tires and seeing very little if any off road use.

[allchevy58]

Before I bought my Duramax, I had a 83' Chevy K20 that I built a 454 stock with RV cam and headers, years later I put in a HO454 crate motor. I did put in a full floater rearend before I put the big block in it. I never had any issues. I towed my 26' travel trailer with my 21' daycruiser behind that. You'll be fine.

[El Dorado Jim]

Originally Posted by mattshea125

Thanks for the input. I guess my biggest concern is towing, As I would like to be able to haul smaller equipment around for jobs occasionally. Or a small travel trailer and not stress the wheel bearings and ball joints out. I have a 11.5 GM14 bolt full floater for the rear which should be good. The truck will be running 265/75r16 tires and seeing very little if any off road use.

I did this swap years ago on my 74 K20,never any problems with braking, you will like the extra power for towing, mine was a 4 spd transmission and I needed to get a flywheel for a 454, if you have an automatic, you will need a 454 flex plate,they are balanced differently than for a 350

[kwmech]

Most of the front winch bumpers weigh more than the difference between the 350 and the 454. Only about a 200# ish difference


ever see how small the 2wd bearings are compared to the 4wd? big or small engine

[ManNamedJed]

HAWK HPS brake pads will significantly increase your stopping power. I have them in my suburban and a jeep.

[mattshea125]

Any idea on what headers to go with on the 454 swap? Seems to be a lot of conflicting info on that topic as well. I will be running a TH400 with NP208 case

[allchevy58]

I used Doug Thorley headers when I did my swap. Fit perfect.

[b454rat]

I used chevelle headers. They fit but not with hydro clutch. Had to shim it out quite a bit. If it tucked em above the frame so nothing was hanging below....