73 GMC crew

firedan · 01-06-2009, 11:48 AM

I have a 73 3/4 ton crew cab 2 wheel drive and want ti install pontiac 455 engine in to replace the 350 that need rebuilt. has anybody done this to help? I case you are wondering why a pontiac it is what i have that is newly rebuilt and tired of it sitting Thanks anyone for there help.

75K30 · 01-06-2009, 12:06 PM

Welcome to the site:

This is pretty interesting. You want to run the old tin indian powerplant in your truck?
This is a fairly easy and straight foward swap, but you will have to make up some engine mounts, and you will have to use the TH400 that has the pontiac, buick, olds bellhousing pattern. I am assuming that you are running an auto.
You will not find headers that will fit, though you can modify a set of Hookers (super comp) to clear the frame. Pontiac engines have a funny set of center exhaust ports and exhaust problems can arrise. Not difficult to fix, but dont expect to install anything 100% bolt on.
Thats about it. Does this engine have any sentiment to you? Other than just having the engine laying around, is there any reason that you do not build a 454 chevy? This would be a direct bolt in with far less modification?
Plenty of buyers for the pontiac.
Which year was this motor born? THere is a huge difference between a 70 and a 71 H.O., and the poor 76 version.
These engines can run well, but are often built on the conservative side. Just wondering what you have stashed over there. Some of these engines are very desireable, and if you have one, you can sell it for more than a 454 would cost to buy or build. Just a thought.

firedan · 01-06-2009, 04:32 PM

well the orig 350 in it is toast yes i would rather stick with chey motor as would be alot easier but have not found the right person wanting this 455 it is a 73 but nothing special just it has been 30 over and rebuilt. just trying to keep cost down on truck for now till i can afford to do the truck right simply put want a quick fix to put the truck back on the road. thanks for the reply. did not know how much would be involved.

silverhairdeere · 01-06-2009, 09:14 PM

ebay or craig list it make it pick up only then buy the motot you want also go on some pontaic form and try to sell it .

shd

gmctrucks · 01-07-2009, 04:35 PM

What is the head casting numbers that are on the 455 block check the passenger head it's right in the center by the exhaust ports? Also what part of the US are you from?
Thanks! GMC

firedan · 01-08-2009, 05:10 AM

I am in Pa near Gettysburg and i will have to check the number the motor is at my buddy shop to to put back together, I got the motor about 5 years ago and for some reason the guy took it all apart. it it was already running at the time as he just rebuilt it and had it in the a car. The engine is so clean you can tell it wasn't running long,so that is where i am on that. If i remember right when i did run the numbers it came out of a 73 parisienne. So nothing rare or special about other than being bored 30 over and looks like head work has been done.

75K30 · 01-08-2009, 08:28 AM

Thats a huge red flag.
Lets put some pieces together.
You have an engine that is 5 years old, it is in pieces, it was assembled at one time and then taken apart again? This assembled engine was run, and almost immediately taken apart again?

Only one reason that the engine came apart after it was assembled and run. Something was wrong. There would be no logical reason to take a complete engine apart, other than the thing was making noise, had no oil pressure, or was such a pile that it was abandonded.

What do you really know about this Pontiac? How did you acquire it?

gmctrucks · 01-08-2009, 08:05 PM

I would really like to know the head numbers this site can help you find the numbers.
www.wallaceracing.com I to was wondering about why it's apart it takes a lot to kill a PONCHO engine and it all leads to a major problem. Maybe.

436'd skylark · 01-08-2009, 10:27 PM

I think this is a cool idea. If done right the pontiac will make way more torque than a 454 will anyday of the week. Should make for a nice truck. but, a few hurdles are in the way. I'd run stock manifolds, either way you'll need some pipes bent to mate to the stock exhaust. You can get stock frame mounts from any v8 poncho powered car and weld/drill them to your frame. there are all sorts of tranny adapters that are cheap to take care of the bop mismatch.

I'd do it, if the 455 was worth anytthing.

firedan · 01-09-2009, 06:46 PM

again i have not a clue to why it was tore back down as in all the parts i have there is no evidence that anything went wrong. the only part that is not with is the cam shaft,and there is no evedence of any problem there either as i have had a machine shop go over the engine complete and with the same result as i have no ideal why it was took back apart. As for the history of the engine i am a third party owner and the gent that i did get the motor from now it was a screamer in a 78 trans am and the person who owned it claims he was getting more work done to it and ran out of funds . other than that i don't know any more about it other than it looks like a new engine that has never been installed. And when i get the # i will post as it is still at the engine shop waiting on what i want to do with it. Oh freind is how i acquire it

01-06-2009, 11:48 AM	#1
firedan Junior Member Join Date: Jan 2009 Posts: 7	73 GMC crew I have a 73 3/4 ton crew cab 2 wheel drive and want ti install pontiac 455 engine in to replace the 350 that need rebuilt. has anybody done this to help? I case you are wondering why a pontiac it is what i have that is newly rebuilt and tired of it sitting Thanks anyone for there help.

01-06-2009, 12:06 PM	#2
75K30 Senior Member Join Date: Jul 2006 Posts: 2,992	Welcome to the site: This is pretty interesting. You want to run the old tin indian powerplant in your truck? This is a fairly easy and straight foward swap, but you will have to make up some engine mounts, and you will have to use the TH400 that has the pontiac, buick, olds bellhousing pattern. I am assuming that you are running an auto. You will not find headers that will fit, though you can modify a set of Hookers (super comp) to clear the frame. Pontiac engines have a funny set of center exhaust ports and exhaust problems can arrise. Not difficult to fix, but dont expect to install anything 100% bolt on. Thats about it. Does this engine have any sentiment to you? Other than just having the engine laying around, is there any reason that you do not build a 454 chevy? This would be a direct bolt in with far less modification? Plenty of buyers for the pontiac. Which year was this motor born? THere is a huge difference between a 70 and a 71 H.O., and the poor 76 version. These engines can run well, but are often built on the conservative side. Just wondering what you have stashed over there. Some of these engines are very desireable, and if you have one, you can sell it for more than a 454 would cost to buy or build. Just a thought. Last edited by 75K30; 01-08-2009 at 12:36 AM.

01-08-2009, 10:27 PM	#9
436'd skylark Senior Member Join Date: Mar 2007 Location: Buffalo Ny Posts: 655	I think this is a cool idea. If done right the pontiac will make way more torque than a 454 will anyday of the week. Should make for a nice truck. but, a few hurdles are in the way. I'd run stock manifolds, either way you'll need some pipes bent to mate to the stock exhaust. You can get stock frame mounts from any v8 poncho powered car and weld/drill them to your frame. there are all sorts of tranny adapters that are cheap to take care of the bop mismatch. I'd do it, if the 455 was worth anytthing. __________________ Joe 89 K2500 Chevy, Wee-Oh-five 285K miles, completly rebuilt needs a motor, bad 1962 IHC Scout All Wheel Drive (Scout speak for locking axles) 152 ci, dana everything else

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01-06-2009, 04:32 PM	#3
firedan Junior Member Join Date: Jan 2009 Posts: 7	well the orig 350 in it is toast yes i would rather stick with chey motor as would be alot easier but have not found the right person wanting this 455 it is a 73 but nothing special just it has been 30 over and rebuilt. just trying to keep cost down on truck for now till i can afford to do the truck right simply put want a quick fix to put the truck back on the road. thanks for the reply. did not know how much would be involved.

01-06-2009, 09:14 PM	#4
silverhairdeere Senior Member Join Date: Feb 2008 Location: land between the lakes tn Posts: 1,118	ebay or craig list it make it pick up only then buy the motot you want also go on some pontaic form and try to sell it . shd

01-07-2009, 04:35 PM	#5
gmctrucks Senior Member Join Date: Nov 2006 Location: Houston,Texas Posts: 3,948	What is the head casting numbers that are on the 455 block check the passenger head it's right in the center by the exhaust ports? Also what part of the US are you from? Thanks! GMC

01-08-2009, 05:10 AM	#6
firedan Junior Member Join Date: Jan 2009 Posts: 7	I am in Pa near Gettysburg and i will have to check the number the motor is at my buddy shop to to put back together, I got the motor about 5 years ago and for some reason the guy took it all apart. it it was already running at the time as he just rebuilt it and had it in the a car. The engine is so clean you can tell it wasn't running long,so that is where i am on that. If i remember right when i did run the numbers it came out of a 73 parisienne. So nothing rare or special about other than being bored 30 over and looks like head work has been done.

01-08-2009, 08:28 AM	#7
75K30 Senior Member Join Date: Jul 2006 Posts: 2,992	Thats a huge red flag. Lets put some pieces together. You have an engine that is 5 years old, it is in pieces, it was assembled at one time and then taken apart again? This assembled engine was run, and almost immediately taken apart again? Only one reason that the engine came apart after it was assembled and run. Something was wrong. There would be no logical reason to take a complete engine apart, other than the thing was making noise, had no oil pressure, or was such a pile that it was abandonded. What do you really know about this Pontiac? How did you acquire it?

01-08-2009, 08:05 PM	#8
gmctrucks Senior Member Join Date: Nov 2006 Location: Houston,Texas Posts: 3,948	I would really like to know the head numbers this site can help you find the numbers. www.wallaceracing.com I to was wondering about why it's apart it takes a lot to kill a PONCHO engine and it all leads to a major problem. Maybe.

01-09-2009, 06:46 PM	#10
firedan Junior Member Join Date: Jan 2009 Posts: 7	again i have not a clue to why it was tore back down as in all the parts i have there is no evidence that anything went wrong. the only part that is not with is the cam shaft,and there is no evedence of any problem there either as i have had a machine shop go over the engine complete and with the same result as i have no ideal why it was took back apart. As for the history of the engine i am a third party owner and the gent that i did get the motor from now it was a screamer in a 78 trans am and the person who owned it claims he was getting more work done to it and ran out of funds . other than that i don't know any more about it other than it looks like a new engine that has never been installed. And when i get the # i will post as it is still at the engine shop waiting on what i want to do with it. Oh freind is how i acquire it