LT1guy

There is a lot of information/misinformation about swapping Pontiac motors into third generation F-bodies, so I thought I'd share some ideas.
The common misconception is that this is an expensive swap. It can be if you so choose, but it doesn't have to be. I'm going to outline different options for the swap, and make suggestions for parts sources and parts numbers where I can.

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Altered State Customs
1987 Trans Am w/455 (in progress)
1985 Trans Am (getting 500ci Caddy)
1997 Camaro SS #359 383 LT1
Co-Builder of RAIF (As seen on TLC's RIDES!)

LT1guy

First step is finding a suitable engine. If you have Pull-A-Part/U-Pull It type salvage yards , that would be a good place to start. I purchcased a 73 455 shortblock and short tailshaft TH400 transmission from the local PAP for about $110...if I had wanted the heads and accessories, it would have been around $175 total. Since I planned to use Edelbrock heads, this was the best way to go for me.
While I can't speak for all areas, Pontiac 400 and 455s are very common in salvage yards here. 455s are typically found in early 70s Grand Prixs and some of the fullsize cars; 400s are much more common, and were available in pretty much all Pontiacs through the late 70s.
If you're not sure of the displacement, its typically cast into the side of the block, and its also evident under the valley pan. The lifter valley will have a two digit number cast in; "50" is 350, "00" is 400, "55" is 455.

LT1guy

Most swappers will choose an automatic transmission, and you have several choices here.
If you are concerned about fuel economy, or just want to be able to cruise at lower RPM, there are several choices available. The TH2004R is a direct bolt in; they were used in Buick Grand Nationals (these are the best ones, but good luck finding one) and most of the G-body cars throughout the mid-late 80s. I have found several in Olds wagons that have the dual bolt pattern, so they could be used with any BOP or Chevy engine.
As an alternative, any Chevy overdrive automatic (TH700R4, 4L60, 4L60E, 4L65E, 4L80E) could be used also, so if your car has a good transmission by all means use it. You will need an adapter plate such as TCI #23001.

LT1guy

If you aren't concerned about overdrive, use a TH350 or TH400. More than likely the engine you pull has one or the other behind it already; all but the fullsize cars will have the short shaft version, which is the one you want. If not, BOP transmissions are very inexpensive...most yards will practically give them away. If you already have a good Chevy TH350 or TH400, you can use the above mentioned adapter to make it work.

LT1guy

Manual transmissions will work also, but this is going to be a little more complicated .
If you have a Pontiac 4 speed setup (T10/Super T10/Muncie), it can be used, but the only snag is clutch linkage. The early Pontiac stuff is all mechanical, and most third gen stuff (83-newer) is hydraulic. While I have never seen one, I have been told that the 82-3 models with a 4 speed used mechanical linkage. Due to rarity, this probably shouldn't even be considered unless you happen to have an original 4 speed car or have all the linkage. The alternative would be to use a hydraulic throwout bearing from Mcleod, and either their master and slave cylinder, or stock third gen items.
Aftermarket transmissions, such as the Richmond 5 speed (non-overdrive) and 6 speed (overdrive) will work either with mechanical clutch linkage, or preferably, with the McLeod hydraulic setup. Any of the above transmissions will work with an aftermarket bellhousing, such as the Lakewood or McLeod.

Project: 85 2.8 bird

Chief Many Horses has motor mount conversion brackets for 326-455 in to 82-92 f-bodies, $89.95 LINK

and long tube D-port headers for this application for $529.95 LINK

more parts, p/n's, and prices as I find them.

LT1guy

If you have a T5 five speed, it is possible to use it, but it likely will not hold up. Lakewood makes a bellhousing for this combo (#LAK-15100, also works with 4 speeds), and it would allow the use of stock hydraulics.
This bellhousing could also be used with an aftermarket T56 if redrilled to fit the T56 pattern (the holes for the T5 are the same as the aftermarket T56s, but are at an angle like a stock T5 installation). McLeod also makes a modular bellhousing that can be adapted to nearly any transmission. I'll add more on this option later (McLeod's site is down). In my personal vehicle, I will be using this bellhousing with an aftermarket T56, McLeod's hydraulic throwout bearing, and either a Tilton or Wildwood master cylinder. Stock hydraulics could likely be adapted also.

LT1guy

Ok, these are the basic parts needed...how do you mount them in the car?
Nearly any stock Pontiac V8 frame mounts can be adapted to the F-body, either bolted in or welded. This will be the cheapest way to go, and will work fine as long as you have a stock K-member in the car. As an alternative, you can buy the above mentioned engine mount brackets from Indian Adventures. These have the advantage of working with any stock V8 frame mounts in the third gens, cutting out any modification and making this a true bolt in. They also serve to lower the engien slightly. This should also allow those of you with a tubular K-member to still bolt in the engine in a clean fashion, without any fabricating.
For transmission crossmembers, it will depend on what trans you are using. If you have adapted a Chevy transmission with a provison for a torque arm, you can use the stock crossmember and torque arm, though you might have to slot the crossmember bolt holes slightly to compensate for the adapter's thickness. For any other transmission, I would recommend a crossmember/torque arm from Spohn. They have them available for nearly any transmission you can think of.

LT1guy

Ok, what to do about the exhaust?
Most factory exhaust manifolds will fit, though slight trimming of the flanges or clearancing here and there might be necessary depending on which casting you are using. Its safe to say that all but the long branch style manifolds will clear the third gen chassis.
Indian Adventures makes headers for this swap, but there may be other, less expensive alternatives. I am still researching this, and plan to try several sets of off the shelf headers when my own project gets to that point. Several second gen headers work on BBC swaps into thirdgens with slight mods, and the Pontiac may be no different. I'll be building my own headers for this project though, since no one makes headers for a twin turbo setup .

LT1guy

Hood clearance can be an issue, so you will be limited to street style intakes with most hoods. A mild cowl or Ram Air style hood would probably be best on a car with a carbureted Pontiac engine, to allow for an adequate air cleaner. It may be possible to get one under a flat stock hood, but at this time I can't say for sure. Edelbrock's Performer and Performer RPM are the most popular choices. If you are going with a Victor series intake, plan on a 4" cowl. Specific clearance numbers for all the above intakes will be posted as they become available.

LT1guy

Wiring your new engine will require a little work, but nothing too difficult. I'd recommend following the instructions here on thirdgen.org for removing the computer controls and going to a traditional carb first, and make sure you have 12v going to the distributor. You can use a factory Pontiac HEI, or your favorite aftermarket brand. Most other hookups will be the same as stock (sending units, starter, etc), but due to different placement on the Pontiac V8 you will have to lengthen or shorten a good deal of the engine wiring. Considering the simplicity of a carb'd V8, this should be a very easy process.

LT1guy

Your existing throttle cable will likely be the wrong length for the new engine. It may be possible to find a suitable one from the salvage yard, or get a new universal type (cut to length) from Lokar. Also, if you are using a TH2004R or TH700R4, you'll need a cable and bracket for that as well. Lokar can help here as well if the factory parts can't be made to work.

LT1guy

More to come...

90firebird

cool thread.. got a friend who would love to do this swap in the future.. stickie maybe??

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swimster

Hood clearance won't be an issue unless youa re using carb spacers and tall air cleaners.. the aftermarket mounts will lower the engine to the same height as an SBC. Factory pontiac mounts will go onto SBC mounts, but they make the engine sit too high. I have a fairly tall torker intake and Q-jet carb. With the aftermarket mounts, it will clear with a ecent air cleaner. It already clears now but I can't put the air cleaner on.

The other item that needs to be found depending on the engine you have is an alrernator bracket. My 400 came from a 73 catalina with AC. This put the alternator VERY high above the Power steering pump. I've heard there is an alternator bracket for putting the alternator on the pass side of the engine down low. And then, if you want even more clearance, there is the oil filter relocation adapter. This lets you completely remove the oil filter housing from the block and just connect a small plate there with hoses to run to a remote filter.

I have found a few more links on another pontiac site with a bunch of pics of this swap.


http://forums.performanceyears.com/e...401#9361042401


You can also go to www.performanceyears.com and go to the "Tech Forums" link and do a search for "3rd gen 455" or "3rd gen swap", things like that.. there's even a link to someone putting a 460 ford into their 3rd gen... seriously.. lol... anyways.. Hope these pics help out and soneone finds some more useful information. I too will post my info as I go.

LT1guy.. Thanks for writting this thread. Nice work.

82FirebirdTA

I would kill to do this swap but since I live in The Peoples Republic of California it won't happen anytime soon...

One slight correction... '84 and newer are hydraulic... '82-'83 were mechanical.

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1983 Trans Am

Looking for GTA

454TA

Question: Will the original bellhousing from a 1972 Firebird 400 fit a T-5 from an 86? If not, can it be redrilled to? It housed an 11"" flywheel which I have for it.

swimster

You will need the adapter plate mentioned above. The T-5 has a chevy bell housing which will not directly bolt up to a pontiac motor. I just bought one of the TCI units and it's a very nice fit. but also.. the torque and power from possibly even a STOCK pontiac 400-455 will just murder a stock or even modified T-5 tranny. I would go with at least a t-56 or find an older stronger 4-spd.

LT1guy

The T-5 likely won't hold up, but if you want a 5 speed you could go with one of the Tremec 5 speeds from Keisler, Fortes, or a number of other sources. They even have a version that will bolt up to your early bellhousing and replace a traditional 4 -speed like a BW or Muncie.

http://www.keislerauto.com/gm/transm...maro_67-69.asp

454TA

My 400 has the 7J2 heads and is from 1972 so it's rated at 200 horsepower. It has more torque than the 305 but not much. I'm sure the transmission will hold up with a minimal amount of power. I don't want to buy another trans. I have the original 400 bellhousing with the original eleven inch flywheel. Will the original 400 bellhousing mate to the transmission? If not is there room to redrill the proper locating holes?

LT1guy

As is, the transmission won't bolt up to the Pontiac bellhousing. It might be possible to redrill the mounting holes, but keep in mind you would need to have it at the same angle as stock (18 deg?), so I'm not sure if there would be enough material there. I know the Lakewood bellhousing mentioned above would work as is, since its already drilled for the T5 and drilled at the proper angle.

swimster

Even with your engine setup, I would still not trust the T-5 behind all the torque of a pontiac engine. it's ALOT more low end torque than even those stock 350 TPI motors.. I have a 400 from a 73 catalina that was a smogger 2-barrel carb and a SINGLE 2.25" exhaust pipe.. now let me tell ya.. that 4800lb car would get up and GO from a dead stop.. It would burn thru a rear tire in a matter of seconds.(did it...) (twice...) but anyways.. I'd say if you had a WC t-5, it may survive a little while without mashing your foot in it alot.. I have a friend in Rochester who put a WC t-5 behind a mildly modified 350 and it's only lasted not even 2 seasons driven only in the summer... ( albiet pretty hard SCCA type driving)... But if you ahve the parts and you can make it work.. go for it. If you want a very good working pontiac automatic tranny, I have the th375 from the old catalina which worked excellent. just kind of grimy. changed the trans fluid all the time. no leaks that I could recall. Not a harsh shifting tranny, but it'd work fine none the less.. If you're anywhere near central NY, you can have it.. I have a tiny one car garage and I need all the space I can get. I also have a 97 Vortec 350 engine I bought by mistake. needs bearings and crank needs a slight polish.. has BRAND new (almost... 800 miles) Vortec heads. motor is all apart. was going to rebuild, but I need to spend more on that to get it going than i would to get the pontiac set up and installed. Besides.. already have 400 hp in the pontiac motor. heh.. what else do I have in the garage... got an 8.5" BPO posi unit i bought for the catalina.. never got around to installing it.

Anyways.. getting WAY of topic.

swimster

Here's another link to another 3rd gen with this swap...

http://webpages.charter.net/ta455/

swimster

Well.. my project is on hold for a little while.. gotta take my block to the machine shop. Need to get new cam bearings and possibly an overbore. that will require new pistons, etc, so.. need to save some money.. At least I have a backup engine for the time being. got a 4 blt main 97 vortec 350 engine I will have to get put back together.. Here's a shot of my tiny one car garage and all the crap I have going on in there. lol.




Also, here's the car I will be putting my 400 pontiac engine into.

18inchboyds

ok while things are being cleared up i wanna ask this . I have a400 or 455 , i have both , and a 4 speed and all the mechanmical linkage from a 4 speed 82 , so will it all fit and be the right length so make it all fit up and work . I really wanna have a poncho engine with a 4 speed. I have the engine in the garage and trans there too , i will have the linkage in a few days, So what else would i need, the poncho bellhousing , and clutch fork , and then driveshaft and then spohn 4 speed stuff. ????/I wanna do this so i need info .

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http://www.cardomain.com/id/ramairetransam

LT1guy

Sounds like everything you need, except for a clutch set. You could probably get the clutch fork from Year One.

18inchboyds

do you have pics you could send me of your setup. Also what did you do for hedders. my trans am is lowered and long tubs would be a nono so i would have to use some manifolds until i could get some money to have a custom set of hedders made or raise the car back up to fit schlong tubes.

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http://www.cardomain.com/id/ramairetransam

LT1guy

My setup is going to be a T56 with a McLeod bellhousing and theri hydraulic throwout bearing, so there won't be anything similar. I'm still in the planning/prep stages (getting ready to weld in the cage and SFCs), so nothing is together yet...just a lot of research over the last couple of years.
I'm building my own headers, since none of the mass produced ones will work for my specific application (twin turbo). I'll post pics as soon as I have them, but time has been very short lately!