# 1969 GTO 454 Big Block Swap



## 1stcarisagto (Oct 23, 2015)

I have a 400 in my gto already(not numbers matching) and I plan on leaving it as original as possible. With that being said I want to drop a 454 to mainly increase torque around 600lb-ft with the added benefit of horsepower. I've read alot about the difference between boring, stroking, having better cams/headers and all. What would be the best course of action and what other modification need to be made to handle the torque?


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## mother (Oct 18, 2015)

Couldn't you just build that motor and hit those kinds of numbers? I understand LS swaps, but I've never heard anyone complain about a lack of torque out of Pontiac motors.


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## oldskool (Apr 26, 2015)

*454 ?*

Welcome to the GTO forum ! 



"... I want to drop a 454..."


I certainly hope that is a typo, and you mean 455 Pontiac. I'm strictly old school Pontiac, and partial the the '69 Goats. I think it's a downright shame to put a Chevy engine of any kind into a '69 GTO ! ! !

You can make all the torque you want with a Pontiac engine. If you really want some low end torque, you can build a 4.5" stroker. Or, if you got the coins, you can go with a 535. 

There is absolutely no GOOD reason to put a Chevy engine into a '69 Pontiac GTO. :nonod: If you just gotta have a Chevy engine, put it into a Chevy body, or at least a later model Pontiac that came with a Chevy motor, and sell the GTO to a Pontiac guy. No personal offense meant. But I make no apology for my opinion.


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## oldskool (Apr 26, 2015)

"...What would be the best course of action and what other modification need to be made to handle the torque?"


The best course of action is to buy or build a stroker, using a good 400 Pontiac block, and a balanced stroker assembly from Butler or Ohio crank. Most recommend a forged crank. They are much stronger than the cast stroker cranks. And the H-beam rods are much stronger than the 5140 rods.

Butler Performance - Pontiac Engine & Rotating Assembly Combinations - Featuring Eagle Pontiac Kits

Butler Performance - Pontiac Engine & Rotating Assembly Combinations - Featuring Eagle Pontiac Kits

Pontiac Rotating Assemblies

http://lenwilliamsautomachine.com/455_Short_Block.html

http://www.sandovalperformance.com/#!product/prd12/2017678915/[email protected]

To handle this much torque, you need a well built TH400, with a 34 or 36 element intermediate sprag assembly.
And, you need at least a 12-bolt rear end. Or, if you got the coins, you can go with an aftermarket 9" Ford or Dana 60. A brand new, complete set-up will run between $2000 & $3000, or a bit more. But, if you build a motor that actually makes 600ft lbs of torque, a stock 12-bolt, with stock C-clip axles won't last long, if you ever put sticky tires on it. 

http://www.coanracing.com/Catalog.asp?ProductDetail=1608

http://www.jakesperformance.com/TH400.html

http://www.ebay.com/itm/9-Inch-Ford...le-/370267475163?_trksid=p2141725.m3641.l6368

http://www.summitracing.com/parts/msr-12bkbfcbbkxg/overview/

Probably wouldn't hurt to use a rear engine plate, to help avoid motor mount and tranny case problems. A JW Ultra Bell on the TH400 would also be a good idea. I tore up lots of parts with 500ft lbs. So, 600 will require some stronger stuff.

https://www.cachassisworks.com/p-137-pontiac-buick-olds-v8-midplate.aspx

http://tinindianperformance.com/Pontiac Engine Mid Motor Plates.htm

[ame]http://www.amazon.com/J-W-Performance-Transmissions-92451-Ultra-Bell/dp/B003PJOMEI[/ame]


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## geeteeohguy (Feb 2, 2008)

What Oldskool says.....and I'll add from experience, Chevy power is overrated, whereas Pontiac power is underrated. I know that today, there are a lot of bad a$$ motors out there, but back in the day, I raced against many a 454 BBC with a 389 or 400 Pontiac, and never lost to one. Not even once. If you build a stroker Pontiac for your GTO, you will_ not _be sorry.


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## 1stcarisagto (Oct 23, 2015)

Its not there that the 400 lacks torque, its that its cheaper and easier to just build off a 454 because there are so many. They're also both GM its not like im putting a ford in it. i'd rather leave my 400 alone if i want to go back to a more original setup. Since im not diving into a pool of coins i know i can get a cheap 454 and th400, 

thanks oldskool for the rear end help i knew something had to be done to handle the torque but what i wasnt sure.


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## ALKYGTO (Mar 29, 2010)

Oh boy, here we go again
...?


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## PontiacJim (Dec 29, 2012)

ALKYGTO said:


> Oh boy, here we go again
> ...?



Na, its like beating a dead horse. :banghead: Not goin' to go there. :thumbsup:


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## mother (Oct 18, 2015)

1stcarisagto said:


> Its not there that the 400 lacks torque, its that its cheaper and easier to just build off a 454 because there are so many. They're also both GM its not like im putting a ford in it. i'd rather leave my 400 alone if i want to go back to a more original setup. Since im not diving into a pool of coins i know i can get a cheap 454 and th400,
> 
> thanks oldskool for the rear end help i knew something had to be done to handle the torque but what i wasnt sure.


If you've got the $5k+ for a 600 foot pound BBC build/swap, I wouldn't expect it to be significantly more expensive to do it with your Pontiac.

Forged rotating assemblies are within a few hundred dollars of each other, yes you'll pay $300 for an intake manifold instead of $150, and the valve-train will be a bit more expensive, but is that significantly more than the cost of a new transmission plus new motor mounts, etc?

Like I said, I get the LS thing (unlike many around here) but I do not get a BBC swap for the power level you're talking about.

(PS It is pretty much exactly like you're putting a Ford in it- You can't even play the 'corporate motor' thing with a BBC, it's a Chevy. Anyone who actually cares about such things will be at least as upset as if you put a 460 in it, which might at least score you some grins for being quirky. You'll even piss off the Chevy guys doing this, they'll tell you that you should have built a Chevelle.)


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