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11-23-2019, 11:27 PM
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#1
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New Member
Springfield
, California
Join Date: Nov 2019
Posts: 1
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454 engine replacement options
Hello all,
I have a very mint excella that started smoking heavily and then knocking. Id like to replace the 454 with something different.
Has anyone put in a GM 6.0L or 5.3L?
Displacement wise both are much smaller but either make more power than a boat anchor 1980’s 454.
The 6.0L would have 360hp and 380ft-lbs of torque. Packaging wise it’s a lot smaller. These can be had from a wrecker for $800 with very low miles from a 1 ton GM truck.
Another option is the GM 350 vortec 5.7L which has 255hp and 330ft-lbs of torque. My wrecker has one of these with low miles for $440 from a 3/4 ton GM truck.
I’m looking to repower on a budget but I do not see any information on anyone ditching the 454 for something smaller, newer and more powerful.
Thanks
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11-23-2019, 11:41 PM
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#2
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Keen amature
1975 20' Argosy 20
Chestfield
, Kent
Join Date: Mar 2014
Posts: 3,535
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Quote:
Originally Posted by Air streamer
Hello all,
I have a very mint excella that started smoking heavily and then knocking. Id like to replace the 454 with something different.
Has anyone put in a GM 6.0L or 5.3L?
Displacement wise both are much smaller but either make more power than a boat anchor 1980’s 454.
The 6.0L would have 360hp and 380ft-lbs of torque. Packaging wise it’s a lot smaller. These can be had from a wrecker for $800 with very low miles from a 1 ton GM truck.
Another option is the GM 350 vortec 5.7L which has 255hp and 330ft-lbs of torque. My wrecker has one of these with low miles for $440 from a 3/4 ton GM truck.
I’m looking to repower on a budget but I do not see any information on anyone ditching the 454 for something smaller, newer and more powerful.
Thanks
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The early 20ft motorhomes came with a 350, and the 454 was an optional extra. Several people have swapped for a crate 350HO (which has over 3x the power) but they are still non-electronic/carburetor units. The hassle with using the modern equivalent will not be the engine but the electronics to support it.
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11-24-2019, 05:07 PM
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#3
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4 Rivet Member
1987 34.5' Airstream 345
Menomonee Falls
, Wisconsin
Join Date: Jul 2010
Posts: 424
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Hey,
As you probably know, a big block vs a small block motor differ in the performance they give you we need low end torque. You won't nessessarily get any better milage or performance from a small block. If she's starting to smoke, it could be as simple as new seals on the valves. They were known to get hard and crack. Maybe all you need is to freshen up the heads. That shouldn't t cost much more than 800 .oo. Do compression test, that lol tell the tale.
If you should decide to go with a small block , try putting a FiTech fuel injection system in. Super easy to install. Mine works great. Cost me I think 900.00 for the kit. You got to get a differant intake though, it looks like a ford manifold. All four holes are the same size. Or get an adapter plate. 20.00 bucks at any auto store. DJ
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11-24-2019, 06:20 PM
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#4
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4 Rivet Member
2021 16' Bambi
2021 22' Bambi
Currently Looking...
North Port
, Florida
Join Date: Mar 2007
Posts: 331
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IMO not enough low end grunt with the 6.0’s. When it’s time for me to replace my option would be the HT502 crate motor. Lots of low end torque and peak hp all below 3k. Rpm
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11-24-2019, 06:25 PM
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#5
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Rivet Master
1972 31' Sovereign
1975 31' Excella 500
Currently Looking...
Benton
, Arkansas
Join Date: Mar 2013
Posts: 5,868
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Quote:
Originally Posted by Air streamer
Hello all,
I have a very mint excella that started smoking heavily and then knocking. Id like to replace the 454 with something different.
Has anyone put in a GM 6.0L or 5.3L?
Displacement wise both are much smaller but either make more power than a boat anchor 1980’s 454.
The 6.0L would have 360hp and 380ft-lbs of torque. Packaging wise it’s a lot smaller. These can be had from a wrecker for $800 with very low miles from a 1 ton GM truck.
Another option is the GM 350 vortec 5.7L which has 255hp and 330ft-lbs of torque. My wrecker has one of these with low miles for $440 from a 3/4 ton GM truck.
I’m looking to repower on a budget but I do not see any information on anyone ditching the 454 for something smaller, newer and more powerful.
Thanks
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An LS motor would be an upgrade, particularly a 6.0 or 6.2 L.
One could be used without a computer with a crank triggered ignition and a new intake manifold to run a carburetor.
As mentioned above, computer kits to run the EFI are fairly inexpensive these days, and they can work very well.
__________________
The fact that I am opinionated does not presuppose that I am wrong......
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11-26-2019, 01:58 PM
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#6
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3 Rivet Member
2015 25' FB Flying Cloud
Sandy
, Utah
Join Date: May 2015
Posts: 229
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Quote:
Originally Posted by Air streamer
Hello all,
I have a very mint excella that started smoking heavily and then knocking. Id like to replace the 454 with something different.
Has anyone put in a GM 6.0L or 5.3L?
Displacement wise both are much smaller but either make more power than a boat anchor 1980’s 454.
The 6.0L would have 360hp and 380ft-lbs of torque. Packaging wise it’s a lot smaller. These can be had from a wrecker for $800 with very low miles from a 1 ton GM truck.
Another option is the GM 350 vortec 5.7L which has 255hp and 330ft-lbs of torque. My wrecker has one of these with low miles for $440 from a 3/4 ton GM truck.
I’m looking to repower on a budget but I do not see any information on anyone ditching the 454 for something smaller, newer and more powerful.
Thanks
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The 6.0 was a purpose built truck motor that would have more low end torque than the others that you have listed and would do a better job. The actual replacement for the 454 was the 8.1 L or 496 ci that is, in my opinion, one of the best motors GM ever made. The 8.2 L 502 ci is a spinoff of that motor and used throughout the boat and hotrod industries. GM sells them as crate motors.
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11-26-2019, 04:06 PM
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#7
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Rivet Master
Vintage Kin Owner
Lin
, Ne
Join Date: Dec 2009
Posts: 2,430
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A 8.1 with an allison sounds good.
__________________
The higher your expectations the fewer your options.
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11-26-2019, 07:13 PM
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#8
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3 Rivet Member
1971 27' Overlander
Kansas City
, Kansas
Join Date: Jul 2018
Posts: 235
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If you're going to go to the trouble to install a new engine then the extra effort for fuel injection will be well worth the while. Apart from increased gas mileage, you no longer have a carburettor washing down the cylinder walls everytime you drive down the road.
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05-04-2020, 06:26 PM
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#9
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3 Rivet Member
1985 34.5' Airstream 345
Bolton
, Massachusetts
Join Date: Jul 2003
Posts: 175
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need a new motor in my 85 345 also smokin and clunking
did you replace or have it rebuilt
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05-04-2020, 07:51 PM
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#10
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Rivet Master
2013 31' Classic
billings
, Montana
Join Date: Feb 2010
Posts: 3,577
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Quote:
Originally Posted by Air streamer
Hello all,
I have a very mint excella that started smoking heavily and then knocking. Id like to replace the 454 with something different.
Has anyone put in a GM 6.0L or 5.3L?
Displacement wise both are much smaller but either make more power than a boat anchor 1980’s 454.
The 6.0L would have 360hp and 380ft-lbs of torque. Packaging wise it’s a lot smaller. These can be had from a wrecker for $800 with very low miles from a 1 ton GM truck.
Another option is the GM 350 vortec 5.7L which has 255hp and 330ft-lbs of torque. My wrecker has one of these with low miles for $440 from a 3/4 ton GM truck.
I’m looking to repower on a budget but I do not see any information on anyone ditching the 454 for something smaller, newer and more powerful.
Thanks
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The 454 has more power than the 5.7...5.3...if you went with the 6 liter..you need all the computers and ecm.....stick with the 454...or go to a Chrysler 440...
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05-04-2020, 07:52 PM
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#11
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Rivet Master
2013 31' Classic
billings
, Montana
Join Date: Feb 2010
Posts: 3,577
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Quote:
Originally Posted by r carl
A 8.1 with an allison sounds good.
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That would be a good engine in a motorhome if you co7ld find one
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05-04-2020, 09:05 PM
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#12
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Rivet Master
1972 31' Sovereign
1975 31' Excella 500
Currently Looking...
Benton
, Arkansas
Join Date: Mar 2013
Posts: 5,868
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454 engine replacement options
deleted
__________________
The fact that I am opinionated does not presuppose that I am wrong......
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05-04-2020, 09:10 PM
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#13
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Rivet Master
1972 31' Sovereign
1975 31' Excella 500
Currently Looking...
Benton
, Arkansas
Join Date: Mar 2013
Posts: 5,868
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454 engine replacement options
Deleted
__________________
The fact that I am opinionated does not presuppose that I am wrong......
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05-04-2020, 09:31 PM
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#14
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Rivet Master
1972 31' Sovereign
1975 31' Excella 500
Currently Looking...
Benton
, Arkansas
Join Date: Mar 2013
Posts: 5,868
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Quote:
Originally Posted by Paul J Mauro
need a new motor in my 85 345 also smokin and clunking
did you replace or have it rebuilt
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If you're mechanically inclined and have the tools rebuilding the engine yourself would be the cheapest way out....
If not, buying a rebuilt engine is the cheapest and probably the best way out....
__________________
The fact that I am opinionated does not presuppose that I am wrong......
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05-05-2020, 05:12 AM
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#15
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3 Rivet Member
1985 34.5' Airstream 345
Bolton
, Massachusetts
Join Date: Jul 2003
Posts: 175
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Quote:
Originally Posted by J. Morgan
If you're mechanically inclined and have the tools rebuilding the engine yourself would be the cheapest way out....
If not, buying a rebuilt engine is the cheapest and probably the best way out....
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i agree leaning toward a rebuild .dont need to hassle with the new electronics
she ran great new about 150,000 miles ago
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05-05-2020, 06:41 AM
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#16
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"Cloudsplitter"
2003 25' Classic
Houstatlantavegas
, Malebolgia
Join Date: Jun 2007
Posts: 20,000
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Quote:
Originally Posted by Shermy1987
If you're going to go to the trouble to install a new engine then the extra effort for fuel injection will be well worth the while. Apart from increased gas mileage, you no longer have a carburettor washing down the cylinder walls everytime you drive down the road.
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X2
Re-manufacture or Crate engine w/ factory warrantee. 👍
Bob
🇺🇸
__________________
I’m done with ‘adulting’…Let’s go find Bigfoot.
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06-12-2020, 05:55 AM
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#17
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"Contact!"
1981 28' Airstream 280
Pierre
, South Dakota
Join Date: Nov 2003
Posts: 64
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+1 ht502
Quote:
Originally Posted by cliffcharb
IMO not enough low end grunt with the 6.0’s. When it’s time for me to replace my option would be the HT502 crate motor. Lots of low end torque and peak hp all below 3k. Rpm
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This is what we did. It’s an expensive experience, and proper support is imperative, either in your own shop or someone else’s. End result for us is a solid power plant that gives us confidence in a rig we plan to keep another 30 years.
The folks on this forum will be your biggest asset, either way.
Kevin
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06-12-2020, 06:48 AM
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#18
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Rivet Master
Commercial Member
2019 27' Tommy Bahama
London
, Ontario
Join Date: Aug 2007
Posts: 1,347
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About 7 years ago a customer with a 345 bought a totaled GMC pickup with a 6.0 and 6peed transmission. They took the engine transmission unit and all the electronics out of the truck and put it in the MH. He had the skills to do it. I drove it when he was done and it worked great, far more performance than the 454 and it was about half the noise level.
He was going to do a GM engine and transmission combination that came with all the electronics but the totaled truck was cheaper and gave him everything.
Andy
__________________
Andrew Thomson London, Ontario
"One test is worth a thousand expert opinions." Tex Johnston, Boeing 707 test pilot
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06-19-2020, 12:29 PM
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#19
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Rivet Master
1991 25' Airstream 250
Oxford
, Oxfordshire
Join Date: Jun 2007
Posts: 1,253
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I believe the Vortec 7400 L29 was the last 454 which married up to the standard P32 chassis. I might be wrong though. http://67-72chevytrucks.com/vboard/s...d.php?t=266963
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08-10-2020, 04:25 PM
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#20
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2 Rivet Member
Currently Looking...
Currently Looking...
Tucson
, Arizona
Join Date: Jul 2011
Posts: 43
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We recently dropped a NEW Chevy 454 into our Magic Bus and its been FANTASTIC... (1985 345)
Now... in addition, we also put in a 4L80E (4 speed trans with locking hub). When installing a new transmission... be sure the folks doing it install a transmission cooler... (sounds basic, but the first shop we went to didn't and its a LONG sad tale. My Personal believe is you need more then the 3 speed transmission for long drives at 65 or 70 mph or so.
We went with the carburetor config because I DIDN'T want to deal with all the computers etc... The 4L80E hooks right up to the 454, and while it DOES have a computer... its not a big deal.
With this configuration, we finished a 2 week trip through Colorado where we topped out at over 11,000 feet of elevation. Engine temps at 200, and Trans temps a 205. NO ISSUES at all.
My advice, TAKE YOUR TIME and ENSURE you have a SHOP that can handle the work... Our experience to get to where we are now took a few years and $5k more then it should have because we started in the wrong shop.
GOOD LUCK !
Todd
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