In over my head

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pagrunt

Geezer
Sep 14, 2014
9,122
15,255
113
Elderton, Pa
A tip on a true dual set up is use the Jegs 2.5" kit (regular & stainless) when the time comes. Alot of us have bought one. Then with the crossmember them, Summit & G Force wil have a double hump for the TH400 (works with the TH200 4R).
 
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Paladin

Not-quite-so-new-guy
Jan 15, 2013
16
9
3
Little late to this conversation, but I'll relay my experience as I have done both swaps into my 81 GP. I swapped a nice 455 with a higher lift version of an 068 cam, RA aftermarket manifolds, Pypes 2.5" duals, modified Q-jet, and T400 with 2500 stall converter. At the time of the swap i hadn't changed the rear 7.5 with its abysmal gearing, but that was next on the list. Anyway, even with the crap gearing the 455 was awesome. To be clear, I have always hopped up Pontiacs and that's where my bias lies. At the same time I wanted to do an LS swap into a project. Then, along came someone looking for a 455 that was already done and was offering good money, so I made the call to sell him the 455/T400 package out of the 81 and that financed my 6.0L swap, to a degree anyway. As already noted, there is a cost difference between the two options, and once the financial dust had settled I had significantly more invested into the 6.0/4L60e than in the 455/T400. It's also more complicated on the electrical side so prepare to go through that learning curve if you keep the EFI. So the takeaway? The 455 was predictably torquey and wonderful. The nose of the car felt marginally heavier than the Chev 265 it replaced, but not to cause any weird handing by any means. In fact, the only reason I say that is because the car felt noticeably lighter in the front with the 6.0. The only mods to the 6.0 I put in were a GM Hot Cam, Holley cast exhaust manifolds, and a good tune. The 6.0 is possibly the "quickest" engine I have ever owned, but that's based solely on my butt dyno. It is VERY responsive and just keeps pulling and pulling. I am very happy with my LS and am glad I did the swap, but it came with lessons. I know people online are proclaiming to do these swaps for $1.49, but they are either extremely lucky, or perhaps a little loose with their details. Either engine will make you very happy and it's sounds more like a case of being spoiled for choice. From a bang-for-the-buck ROI, it sounds like, for you personally, that the 428 is the way to go, all things being equal. The LS is a great choice as well for many reasons, but will challenge you a bit more on install and in the pocket book. Sorry if all of that muddies the waters more than it helps! Best of luck with your choice. IMO, you win either way.
 
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el camino ss 84

Master Mechanic
Oct 23, 2016
377
223
43
Nw okc
I use to love the idea of swapping a ls style motor in a gbody when they first came out in the corvettes and camaros around 2000. But since there a common swap now a days like how 350 sbc use to be before the ls engines. I hate seeing them in everything now a days making all car's with them boring and not impressive. So I with my little rant over. I would say enjoy what you have and stay with the Pontiac motor get it running then make upgrade as you see needed down the road. If it's going to be driven a lot going with a overdrive transmission would benefit some or just stay with the th400 if it doesn't see much miles. Either way you have the final say.
 
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lilbowtie

Comic Book Super Hero
Jan 7, 2006
3,460
3,965
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Canton Mi
Like so many others, questions and or advice is asked and not to be heard from again.
 
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PBGBodyFan

G-Body Guru
Mar 3, 2009
792
1,220
93
Wisconsin
Another reason I like this forum, not all people are brainwashed into thinking an LS swap is the end all-be all and only correct way to go about it. I'm way late to this thread but also vote keep the Pontiac plant since you have it and it's literally in the car on top of it. Different, cool and should have plenty of power you seek.

That said I probably will LS swap my LeMans but will never join the a-hole contingent from that camp that seems to be all over Facebook, a Pontiac motor is the other alternative and I will have a year or two to think about it. Nice to see different things being done and many different ways to get there.
 
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Northernregal

Sloppy McRodbender
Oct 24, 2017
3,359
12,826
113
Red Deer, Northern Montana territory
Big poncho is a damn cool combo. I wouldn't LS swap that and I am fully embracing the LS coolaid.

Ram Air restoration manifolds, 6X-4 heads and an 068 or road paver roller cam from SD Performance and a Performer RPM. It'll make 450hp but 550ft/lbs. Tallish gears with the TH400 would be a super fun car.
 
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