454 swap

Laura G · Veteran Member

454 swap

4SPEED427 · A Poncho Legend!

I assume the original engine was a blue 350? The US Pontiac 350?

If so, I suspect Clint ( seventy2plus2) will able to help you figure it out as soon as he sees this. He knows 70's pretty well.

67Poncho · Uber Guru

Carl Stevenson wrote:
If so, I suspect Clint ( seventy2plus2) will able to help you figure it out as soon as he sees this. He knows 70's pretty well.

(lol) Hey! Clint isn't the only one that had/has 10-12 '70's kicking around! BUT, I did put a smallblock in my '70 Cat in about '98... I bolted the frame mounts onto the engine and sat everything, including the transmission down in place.. (BB mounts will be the same) But I do believe I used the newer mounts of off the '78 Chev 1/2 ton the engine came out of... If you are not worried about the "original" look, as evidence of using the Chevy engine, I would suggest using the newer mounts as they sit nice and flat allowing easier positioning... I will go out later and snap a pic of my Catalina...

Fuel line will also have to be rerouted as it comes up the drivers side of the frame in the American Cat... easy though...

4SPEED427 · A Poncho Legend!

I'm sorry Vince, I always think of you with just Canadian Pontiacs, and not with 70's, just 67-68's.

67Poncho · Uber Guru

Carl Stevenson wrote:
I'm sorry Vince, I always think of you with just Canadian Pontiacs, and not with 70's, just 67-68's.

Easy big fellah! This isn't Johnnee you talking to... Be a little tougher!!! (hahaha) Actually, I have almost as many '70's as respect to my '67's.... The only one missing is a '65... and I own just one '69....

All good as they are all basically the same anyways.... exception being the Americans...

In my yard as of now....

2-dr/ht

2-wagons

4-2+2's

The Cat 4dr h/t

Parted 6 others...

-- Edited by 67Poncho on Saturday 19th of December 2015 12:23:53 PM

ARCADIAN · Poncho Master!

That 350 turbo may not fit if it's a BOP one. If it fits it may not last long, that 454 will have a lot more torque. You may want to consider a 400 turbo. Just my 2 cents.

-- Edited by ARCADIAN on Saturday 19th of December 2015 02:24:59 PM

seventy2plus2 · Canadian Poncho Superstar!

I can't offer any advice as the Catalina chassis is somewhat different than my 2+2, Laurentian & Parisienne chassis. As Vince mentioned, the fuel line on a Catalina comes up the drivers side frame rail, so that will need to move the the passenger side, and on a Catalina the battery is on the drivers side, and that will need to move to the passenger side due to changing starter positions. If going with a 454 motor, I wouldn't bother with a Turbo 350, step up to a Turbo 400 to handle the torque.

mad65 · Veteran Member

I stuck a 496 in my Acadian with a 350 behind it and I have not been nice to it and I can't get the tranny to blow up.

427carl · A Poncho Legend!

mad65 wrote:
I can't get the tranny to blow up.

Try this 1. Leave transmission in neutral 2. push gas pedal to floor 3. check for obstacles in front. 4. Pull transmission lever to drive 5. repeat as necessary

Laura G · Veteran Member

yes it was a pontiac 350

Laura G · Veteran Member

Thanks Carl. I bought the old style mounts thinking it would be easier, I have the motor, 350 turbo positioned in the car where I believe it should be. I am going to leave the factory tranny cross member in its original spot and I am going to weld a bracket to the front to mount up to shorter tranny mount.I will have to get a longer drive shaft, pictures would be greatly appreciated. Thanks

Laura G · Veteran Member

considered the 400 turbo but the motor is little more than factory not big power for now. A friend suggested running the 350 because it takes less horsepower to run and it will handle the torque that I have for now. End game 500 horse with muncie 4 speed rock crusher.

GrtDanes · Poncho Master!

That might be alittle too much juice for Tylers rat rod for now don't you think??

Laura G · Veteran Member

It might be Grt Danes!!!! I will post a pic of his rat rod peddle car he just made!

67Poncho · Uber Guru

'70 Cat Drivers Motor Mount.JPG

'70 Cat Passenger Motor Mount.JPG

From what I remember, I snipped the top inside of the mounts off... there was a bump on the frame and they wouldn't sit flat... Then I welded both halves of the mount back together... (I think!)

-- Edited by 67Poncho on Sunday 20th of December 2015 02:29:16 PM

73SC · A Poncho Legend!

ARCADIAN wrote:
That 350 turbo may not fit if it's a BOP one. If it fits it may not last long, that 454 will have a lot more torque. You may want to consider a 400 turbo. Just my 2 cents.

-- Edited by ARCADIAN on Saturday 19th of December 2015 02:24:59 PM

Little known fact is that GMC and Chevy one ton trucks of the early 80's on were factory equipped with 454 CID V8's and Turbo Hydramatic 350 transmissions. I've been running a 40 year old THM 350 behind my 454 for the last 4 years.

jmont64 · Canadian Poncho Superstar!

The key to testing these trannies too is how you are hooking up. If you are just peeling a strip good chance your tranny will be fine but if you have it so it hooks up you will be testing it.

Laura G · Veteran Member

thanks for the pics 67 poncho. thanks for the hummor great dane ty will have a good laugh. i had a very productive day today and every thing is were it belongs and centered. fabed up new tranny mount and measured every thing 30 times just to be sure so its ready to be permanent fixture . if anybody gcould give me a part number for the headers i need it would be appreciated 454 in full size pontiac

thanks Jon

4SPEED427 · A Poncho Legend!

73SC wrote:

Little known fact is that GMC and Chevy one ton trucks of the early 80's on were factory equipped with 454 CID V8's and Turbo Hydramatic 350 transmissions. .

Ray, I want to disagree with you here. Can you offer proof of this?

I've worked at a GM dealership since 1980 and have never seen or heard of a TH350 behind a 396, 427 or 454 in any production vehicle. I can't believe GM would open themselves up to warranty claims that would come from a one ton big block with a TH350.

And if you prove me wrong, I'll have to call you "Uncle" Ray!

73SC · A Poncho Legend!

Yes Carl excuse me, I made an error it was earlier, 73-76 that got the 454 THM 350 combo on 1/2 and 3/4 tons.

CLICK HERE

"The standard transmission matching the LE8 454 on 1973 to 1987 trucks was the four-speed Muncie manual. The Muncie four-speed manual with overdrive was available on 1982 to 1987 models. The 1973 to 1976 half- and three-quarter-ton trucks with the 454 received the TH350 three-speed automatic."

Read more : http://www.ehow.com/info_8213484_454-engines-were-chevy-onetons.html

-- Edited by 73SC on Sunday 20th of December 2015 09:15:15 PM

66 Grande guy · Canadian Poncho Superstar!

I know that my 66 396 in my Grande came with a Powerglide(which I still have) if that helps muddy the waters even more!

4SPEED427 · A Poncho Legend!

73SC wrote:

Yes Carl excuse me, I made an error it was earlier, 73-76 that got the 454 THM 350 combo on 1/2 and 3/4 tons.
CLICK HERE
"The standard transmission matching the LE8 454 on 1973 to 1987 trucks was the four-speed Muncie manual. The Muncie four-speed manual with overdrive was available on 1982 to 1987 models. The 1973 to 1976 half- and three-quarter-ton trucks with the 454 received the TH350 three-speed automatic."

Read more : http://www.ehow.com/info_8213484_454-engines-were-chevy-onetons.html

-- Edited by 73SC on Sunday 20th of December 2015 09:15:15 PM

I'm still not buying it!

I'm going to look for GM sales literature for those trucks. I know of two short box 2wd 454 pickups that were in Morris, bought brand new 73-74 and both those trucks had TH400's.

I'll keep looking!

Elroy · Poncho Master!

I had a 76 454 3/4 ton that our dealership sold new and I bought it with only 20,000 miles on it. TH400 2WD

You will probably have to find a long tailshaft tranny as that's what those cars came with. Also , the crossmember is different for a TH400 likely, but usually you can modify the original and also look for dual drilled holes on the frame sometimes you can move it.

goushdds · Addicted!

66 Grande guy wrote:
I know that my 66 396 in my Grande came with a Powerglide(which I still have) if that helps muddy the waters even more!

I thought we had renamed them to the "powerfulglide"

I much prefer that name as it gives my 64 some much needed power biggrin