Swapping Pontiac 350 to Pontiac 400 or 455?

[TJCOLD]

I'm new here and a novice so please go easy on me as I have a lot to learn . I have a 1972 Pontiac LeMans Lux that has the original Pontiac 350 in it. I'm concerning swapping in a 400 or 455. I have a couple of questions I hope you guys can possibly answer or help me understand. (My car is 20 years older than me)

1. I know that the 400 bolts up easily, but how about the 455?

2. Would you all recommend a turn key crate engine or a refurbished block that needs the pulleys and access?

3. How default would the swap be on a scale of 1 to LS nightmare?

4. Is there any glaring hurdles that I'm to too noob to have concerned?

 

[Kraig1957]

The engine swap is really easy if you get a Pontiac 400 or Pontiac 455 to replace the Pontiac 350. Different GM divisions put the starter on different sides of the engine. If you are using an automatic you may also want to go to a THM 400 automatic if only using a THM 350. The THM 400 is less sloppy and can handle more horsepower.

When my 350 transmission pump bit the dust, I had a THM 400 transmission installed as a replacement. That required a change in the propellor shaft. I got a Pontiac 400 V8 out of a 1971 GTO at a local wrecking yard and took it to a machine shop and had it rebuilt.

 

[TJCOLD]

The engine swap is really easy if you get a Pontiac 400 or Pontiac 455 to replace the Pontiac 350. Different GM divisions put the starter on different sides of the engine. If you are using an automatic you may also want to go to a THM 400 automatic if only using a THM 350. The THM 400 is less sloppy and can handle more horsepower.

When my 350 transmission pump bit the dust, I had a THM 400 transmission installed as a replacement. That required a change in the propellor shaft. I got a Pontiac 400 V8 out of a 1971 GTO at a local wrecking yard and took it to a machine shop and had it rebuilt.

Hey thanks so much for the information brother. I'm looking at getting a crate 455 from Butler or somewhere.

 

[Jono]

I built a 400 motor for my 68 LeMans worse part about it was getting the pistons took like 6 months for Keith Black to make them .. but runs great plenty of horsepower for going to show's

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[Jono]

Mine

 

[TJCOLD]

Mine

Beautiful

 

[Jono]

Beautiful

 

[Classics Fan]

I'm new here and a novice so please go easy on me as I have a lot to learn . I have a 1972 Pontiac LeMans Lux that has the original Pontiac 350 in it. I'm concerning swapping in a 400 or 455. I have a couple of questions I hope you guys can possibly answer or help me understand. (My car is 20 years older than me)

1. I know that the 400 bolts up easily, but how about the 455?

2. Would you all recommend a turn key crate engine or a refurbished block that needs the pulleys and access?

3. How default would the swap be on a scale of 1 to LS nightmare?

4. Is there any glaring hurdles that I'm to too noob to have concerned?

Looks like you have a nice car. What’s the health report on the 350? Personally, I’d look at the costs of doing whatever I’d need or want to do to wring performance from the car’s original engine before spending the money to replace it, even if that meant rebuilding it. Just my $.02.

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[TJCOLD]

Looks like you have a nice car. What’s the health report on the 350? Personally, I’d look at the costs of doing whatever I’d need or want to do to wring performance from the car’s original engine before spending the money to replace it, even if that meant rebuilding it. Just my $.02.

Hey bro, 2 cents always welcome. Thanks. The 350 is in pretty good condition. I just recently upgraded the carb and threw in a HEI distributor. It sounds amazing. I just know that there is only so much power I can ever get from a Pontiac 350. But it is hard contemplating taking out her original heart. That's way I settled on a Pontiac 455 over and LS. It's a middle ground for me.

 

[Classics Fan]

Yeah, very clean. Much like mine. It looks like you might have a leak coming from under the brake master cylinder lid (tighten by bending the retaining wire). I would also untie the spark plug wires and secure them with wire separators to avoid possible arcing. Good luck!

 

[TJCOLD]

Yeah, very clean. Much like mine. It looks like you might have a leak coming from under the brake master cylinder lid (tighten by bending the retaining wire). I would also untie the spark plug wires and secure them with wire separators to avoid possible arcing. Good luck!

Thanks, I'm pretty happy with it at the moment. I appreciate the tips, I hadn't noticed the master cylinder leak. Hope to talk with you again soon bro.