I currently have the stock 305 in my 83' Trans Am, and I've been offered a 6.3L engine to put in my TA. I'm told it would fit, so I'm wondering what I'm going to need to do to get an engine like that in my car. Are there any good books I can grab from the library, or other resources for someone who's never done a motor swap before? What would you guys reccomend? I have the shop space and all the tools I need, and an experienced mechanic friend, but I'd like to have an idea of what I'm doing before I throw myself into this project. Thanks a lot!

Forgot to mention, stock 4 speed auto tranny (don't know the model number).

the 400 is the same exact size externaly as a 305 it is a direct bolt in you wont have any probs at all. it should bolt to ur tranny also but im not shur ehow much horse it will take befor eit pops because the 400 has a lot more torque then that 305 does.

I don't know what a 6.3 liter is. A 400 is 6.6.

What is this motor? Where did it come from?

lol i thought he was talkign about a 400.

6.3 should be a 383

What year is the motor, and does anyone know what year they switched the side the dipstick was on?

Ben

Sorry, just got the specifics today. It's a 6.6L engine from a 1971 trans am. It's a 2 bolt pontiac engine.

That will in no shape, way or form be a bolt in motor like the sbc motor would have been. It has been done but takes more fabricating.

Ben

Correct me if im wrong, but shouldn't a pontiac 400 bolt right into a pontiac TA just as easy as a chevy 400 would in a chevy camaro? just seems like the logical thing.

Ryan

Third gen T/As and firebirds never came with pontiac V8s, they came with chevy V8s.

They stopped putting 400 pontiacs into T/As in '79.

Yeah, i knew that they had quit using the 400, but i did not know that they used the chevy. not that it would make any difference, there pretty much the same. but i just thought that the mounts and every thing else that you would have trouble with would be the same going from a pontiac to a pontiac. but what your saying is that bolting in is the same for a third gen firebird and camaro? if so then you would want a 400 sbc to put in a firebird.

Thanks for the advise
ryan

p.s. im about to drop a 400 sbc in my 89 iroc, but im going all chevy so no porblem here. except money

Yep, thirdgens had chevy motors be it a firebird or camaro. You have to use a different trans and motor mounts, exhaust, and probably some other stuff to get a pontiac motor to fit.

Ben

Are you guys sure? It's out of a 71, so its the exact same block as the pontiac 350.

Um, no.... Being a former 78 T/A Owner I can tell you a 400 Big Block does *NOT* Drop right into a 3rd gen.

I would seriously consider putting a TH350 Trans behind the 400 if you drop it in your thirdgen. You'll have to have your driveshaft cut down a bit, but you can by an aftermarket trans crossmember and mounting kit for less than $100.00

I think a stock 400 with headers, good exhaust and a good intake setup would shell a 700R4 trans within a month.

Also, think of this. I've seen people drop 454's into 3rd gens, and they wind up only being good for one thing..... 1/4 Mile Drag Strip.

Yes that is true but your 1983 T/A had a Chevrolet engine stock from the factory (same as all 3rd & 4th gen Firebirds, except the TTA). So yes the 400 and 350 Pontiac are the same but the 400 pontiac and 305 Chevrolet (which you have in your car) are totally different, will not work unless you want to spend more money than it's worth to do. Just build a 400 Chevrolet.

Later, Garrett

Ok, so to put the 400 pontiac in this is what I need to do:

Cut down my driveshaft, buy the trans crossmemeber and mounting kit for $100, buy a th350 transmission, and buy the mounting brackets for a pontiac 400 at chiefmanyhorses.com?

How much would a th350 transmission cost? Is it a part I could find at a junk yard?

Edit: just read the post 2 above more thoroughly.. isn't this considered a small block engine?

Unless you have a 400 pontiac with crazy power to drop in the swap is not cost effective. If it's a stock 400 the best route is to get a Chevrolet 350 or 400 out of a Junkyard and put it in. The Pontiac 400 swap is a good amount of work and money.

And the Pontiac isn't a Big Block, but it's not a Small block either, it's a Pontiac block, which is totally different than a Chevrolet Block (Big or Small).

Later, Garrett

The motor has just been rebuilt, painted, it has a killer intake manifold on it, and really nice chrome GTO valve covers, so it's a really sexy engine. Plus I'm picking it up for dirt cheap (daughter's boyfriend discount! ). Anyway, so is what I outlined above all I need to do?

Edit: The Engine Mounts I Referred to

Ps, will I need to get new headers and a new distributor? I heard the distributor mounts in a different place.

I doubt it. You may have to go with a bigger radiator, but might be able to get away with the one thats in there. You will have to get accessories that will fit the pontiac motor. I dont know, but you could possibly have hood clearance issues and need a cowl hood. You will have to see if there are headers made that will fit the pontiac motor and fit in the car, and if not, have some custom made. You may need to do some minor stuff like some slight fuel line rerouting and crap like that also. It wouldnt suprise me if you ran into a few other things also.

Yes, Pontiac 400BB (yes it's a Big block! ) will require a low profile intake, and/or cowl hood.

You may want to sift through Car Craft back issues. They had an F-Body big block project that spanned several issues. (early 90's issues)

(I almost dropped a 454 in my 85 Several years ago, but decided to do some serious magic to the 2.8 SFI Engine instead )

So at minimum here's what you'll need, In my opinion:

Good Radiator
AC Delete (forget about having ac with that big of a motor in the car)
Good front springs and HD shocks
fuel line mods, maybe an aftermarket fuel pump
exhaust work and mods
SFC's
Tower brace
TH350 and modified driveshaft
high quality torque arm (400's and 454's are torque beasts)
low profile intake and carb

a whole lot of time, money for $5.00 odd and ends, and a few cases of liquid courage. repeat as needed.

If the 400 is a stock motor, I do agree with everyone else in suggesting you forget about it and find a good L98, hell even building up your 305 would be cheaper and easier.

(cam, headers, exhaust and heads do wonders for a 305)

if you plan to build up the 454, I'd still say to maybe try to "Trade" it for a 350 or something.

Then again my 78 had a balanced/blueprinted 400 and pulled high 10's with drag slicks. I'd hate to know what my motor would have done in a newer, lighter f-body (twist the frame, grenade the 700R4, etc...)

Oh.... by the way.... make sure the motor isn't an Oldsmobile 403.... Almost everytime I tried ordering parts the parts guys would say "Pontiac never made a 400, it's an olds 403"

*IF* that motor is a Pontiac 400, it's very rare and worth a good chunk of change. (only used in 77 and part of 78 if memory serves right) At some point in time Pontiac started using the olds 403 in place of their 400.

One last thing.... wanna pull your motor to change spark plugs? :-)

Actually, they used the pontiac 400 from 67 to 79. They used both the 403 and the 400 at some times. You could order either one. My brother has a 77 Trans Am with a 400 Pontiac motor. They are not considered big blocks or small blocks, but are bigger(definately wider) than a sbc. Also, it wouldnt suprise me if you had to pull the motor to change spark plugs but you may be able to get them from the bottom. Those motors just looking at them are wider and going to be more cramped for exhaust and plug access.

Ben

Ah, thanks for the tidbit on the Pontiac 400.

I had been told (even by the shop that built my motor) that technically it is a big block, probably due to the wider stance of the block.

I guess we agree on the "Olds 403" Myth. :-)

(borderline off topic) Interested in selling your old 350? :-) I'd be interested if it's an L98 in good shape.

As for the headers, I do know the car craft article showed some pretty nice tight clearance headers from one of the major vendors (hooker? Hedman?) that were designed specifically for BB motors in 3rd gens.

the turbo 350 you have to find will need to have the B-O-P bolt pattern. The SBC bolt pattern will not match up to the back of that pointiac block.

Ok well I gotta say, I've heard some pretty compelling arguements against buying this 400. Thanks a lot for all of your help guys

It cant just be for a big block. He would need to get pontiac headers. I am not saying that there is not enough room to put them, just that he will have to have ones that are specifically for a thirdgen with a pontiac motor.