1981.pontiac lemans engine swap

[kingchris]

Just personal curiousity but why a Buick 455? Not knocking the motor as such but Pontiac had a 455 of its own back at the start of the 70's. Kind of pc-ish but those Poncho big blocks were torque monsters that also shared the same basic architecture as their smaller counterparts in that the basic block casting was the same from the 350 through to the 455; the block actually had enough internal meat to its bores that they could be punched out, plus there are some serious stroker kits available aftermarket. I actually have a TH400 sitting on the transmission cart right now that has a bellhousing drilled exclusively for the Pontiac. My former neighbor raced them and had blocks and parts in his garage for decades. The transmission sat outside in a lean to forever,almost, and when they knocked the leanto down and carted off the stuff still in it, I bought the unit off the salvager and drug it back to my place. It looks as nasty as a junkyard dog but the fluid inside is still up and clean with no burn smell to it. The front cover may need a new seal and the input shaft needs some serious cleaning but if nothing else it is a great core that is hard to find these days.

There u go hard to find. I couldn't find any . Buick is the only one I could find at a decent price. I looked and looked and looked it's tough to find those Pontiacs cause everyone sees the same

 

[kingchris]

Your car has an 8.5 already? After all the threads I’ve read here on them, I’m curious as to how much power they can really handle (stock). Even Quick Performances 9 inch is only good to 400+ before you buy they’re Yukon. According to them. Any of the GM big blocks woujd pulverize rear tires. All 3 Divisions of the 455s were used so briefly though, cost and availability of parts would be a big concern. I really like builds that are unique.

Yeah that's what I was doing getting all together everything needed before I was to actually purchase the block and transmission.

 

[kingchris]

Yeah that's what I was doing getting all together everything needed before I was to actually purchase the block and transmission.

Thought of going with the olds 455 but someone told me Buick would be better.

 

[565bbchevy]

A Pontiac 455 would have been nice to have in there but the issue with any BOP V8 is the lack of aftermarket support, the costs of parts and the dwindling number of shops that actually know how to build these and fix their weaknesses. IMO

 

[500/600]

Thought of going with the olds 455 but someone told me Buick would be better.

Don't let those 'someones' lead you down a bunch of rabbit holes. You need to make a plan and stick to it. That being said, this someone has built Olds, Buick, and Pontiac 455s. Buick is my favorite, but for no great reason. They are all good and they are all quirky in their own way. The Olds is the easiest of the three to find around here, the Buick second. The Olds likely has the best support from the common aftermarket of the three, the Pontiac second. The Olds is reasonably priced to find a good rebuildable engine. The Olds (not 455) came in these cars and the 455 is a proven bolt in.

I would personally look for a Pontiac 455 since you have a Pontiac. I would 'settle' for a 400 Pontiac as they are fairly common and have great potential without any glaring weak points.

 

[spidereyes455]

Of all the BOP 455's the buick is actually the most difficult one to install because there are no holes for it in the frame already. You will need a set of frame and motor mounts for a 64-72 a body and install the engine and trans where they should be with mounts bolted to the engine then mark the location of the mounts on the frame, remove engine and drill holes for the mounts, bolt them to the frame then reinstall the engine.

 

[spidereyes455]

The Olds and Pontiac 455's use the same respective mounts as their smaller displacement siblings and drop right in.

 

[pagrunt]

I'd say any Pontiac. Some of those "smaller" big inch motors are still out there, just waiting to be found. A 428, 421, 389, 400 can be found in the B body cars & earlier GP's. As with any non Chevy there is always that parts source & knowledgeable shop issue out there.

 

[500/600]

A 428 would make a nice but not impossible find (390hp stock I believe). A 400 should be easy enough to find.

 

[spidereyes455]

Even a 350 Pontiac can be a good performer not to mention cheap since most poncho guys look down their noses at them. Bolt on an early set of 72cc heads to get the compression up to 9.0 a 4bbl stab in an 068 cam with HO exhaust manifolds and stuff it in front of a 4 speed or an auto with about a 2500 converter.