Help please with a 78 pontiac firebird motor swap

Hi guys im Alexx

I own a 78 pontiac firebird and I love my car it is beautiful.  The paint is fresh and it is in cherry condition.  Its a firebird not the trans am but it is of course almost identical to the TA.  Sadly it is the v6 model 3.8L 231 with a pathetic 105 hp.  I feel like its time to make my car into the beast that it should be.

I am eyeing up a pontiac 350 5.7 v8.  The thing is, I know nothing of the engine bolt mounts, and no idea if it will bolt right up into my car or not.  Thats what I am trying to get an answer for.  Obviously its no small task and I will need a new tranny carb oil pump header exaust distributer alternator starter (fuel pump and radiator?) you know the whole nine yards, most of which is available at summit racing.  I have swapped a few engines in my short life so I feel confident but I am not so famillar with these GM motors.  It is the pontiac 350 and not the chevy one so hopefully it will bolt up as well as the transmission but fo course I need to be sure. speaking of transmissions does anyone know what kind of tranny would be ideal for my uses?

My car is my baby and it is beautiful but I always felt like its lacking with the wimpy 6 and im sure you all agree on that too.  I would never sell this car and I know what they CAN be with some work so hopefully mine will turn out good.  This is the last step before I am content with my pretty canary yellow girl!!

Any and all info will be greatly appreciated.  

Not a terribly hard swap if you get all the parts with the new motor- carb,intake and exhaust manifolds, motor mounts and front accessories. First off, you will have to change the frame mounts to the ones for a TA with a 400, the side brackets from the 350 should work as long as it's a 70 or newer block, if it's older you need the newer block brackets and one of the adapter kits from Year One or Performance Years. The rad, fan shroud and hoses will have to come from a TA 400 as well. The accesories and brackets- alternator,power steering pump, A/C compressor will have to come from a Pontiac V8. The trans should bolt up as the Buick and Pontiacs use the same bolt pattern,the torque converter will bolt up to the 350 flexplate. The exhaust crossover pipe is different (use the 400 part) but the rest of the system will work, or switch to duals. Front springs may need to be replaced, check ride height after the swap. The only other thing that comes to mind is the fuel line and wioring, the V6 has the fuel pump and the starter on the right, the V8 will be on the left(driver's )side and you will have to extend the line and reroute the wiring and move the battery to the driver's side like the V8 cars. That might mean changing the rad overflow bottle too, I can't recall what the V6 setup looks like. Hope this helps.  
A little help... 'cause we don't all have to learn the hard way!

Ok thank you a ton first off this helps me immensely.  I have done a lot of research on the subject and have got a pretty solid game plan.  Im going to buy a remaned Pontiac 350 short block all stock cams rods and pistons.  Drop some heads from a 400, a new 4bbl carb and intake manifold, new radiator, distributer, alternator, harmonic balancer, oil pump, starter, oil pan, mounting brackets, water pump, (fuel pump?), power steering pump A/C compressor.  I also think now would be the perfect opportunity to convert the R12 A/C with a conversion kit.

I will have to head to the junkyard and see if I can find me a fan shroud for a v8.  My car has the base model hood Im worried there may be clearence issues with a high rise manifold, hopefully it will fit under my hood though.
Do I need a new wiring harness as well?

Hm that is interesting that the battery is on the other side, cuz yeah mine is on the passanger side currently I will have to think about this.

I was going to use the stock pontiac 400 headers since I have heard they perform pretty well and I see a lot of them in decent condition at the junk yards so that should be easy.  
I guess I will just have the exaust done at the muffler shop and im pretty sure if I get dual exaust its going to need 2 cats to pass smog..the emissions laws really suck where I live haha.

Thank you very much for your detailed response!  

Alexx, your welcome, glad I could help. Be careful what heads you get, you don't want the compression to be too low. Maybe try to get a complete long block instead. The late smog 400 heads have 101cc chambers while the 350's use about 95cc to get 7.6:1 compression ratio, if you use the larger heads, the motor will be a stone! I think most hi-rise dual plane intakes will fit your hood, the real problem comes when you try to use a TA shaker hood, it gives you less clearance. You're right about the cats and the A/C conversion, good time to do it. Have fun!  
A little help... 'cause we don't all have to learn the hard way!

Ha Barney you are again 100% correct.  Using 400 heads would murder my compression ratio I wasnt thinking about that!  The 350 heads seem to be around 93cc or so?  I gotta find me either a set of 6x-4 pontiac heads or like you said a full long block.  Ha there I go again trying to cheap out im glad I didnt jump into that too hastily!

Sounds good on the intake clearance that is very refreshing to hear that it will (most likely) fit.
Are the exuast and intake planes the same from a 350 to a 400?  I noticed that these motors look pretty much identical from the outside, but sometimes looks are decieving.

Now Barney maybe you can answer me one more question if it is not too much trouble.  What kind of performance can I expect from this mostly stock 350?  Obviosly I am not going to the drag strip as this is just a daily driver street car, im just hoping I can burn the tires a little and have a pretty mean sounding car!  Just looking for a cool street car with a little power, but nothing serious, just as long as it outperformes my little 6 banger I will be pretty happy.

Thank you a ton! I really appreciate it!  

Alexx, if you are still looking for a 350 to build, look for a 69-73 motor as they have smaller chamber heads and are rated between 8:1 and 9:1 cr. They will have smaller 1.92" intake valves but that won't hurt a 350 too much. Another option is to use any 350 short block and use early 400 heads for big valves and higher compression. Use a cam in the 200-215 degrees duration at .050" lift, the Pontiac 068 cam is a good choice and is available from most resto companies and cam companies. Use a factory 4bbl intake or Edelbrock Performer (not RPM) and 2.25" dual exhaust with turbo mufflers and stock manifolds ( I don't think headers will be worth the hassle on this level of performance).
With a gear ratio of 3.08-3.42 and a mild 2000-2200rpm converter, you should be capable of low 15- mid 14 second 1/4 mile times at around 90 mph if everything is in good shape and tuned well, depending on the gear you choose of course. That will put you in the running with the every popular standard- the 5L Mustang. This is basically how my Formula (see Reader's rides) will be setup next summer, right now the 2.73 gears are holding it back big time, as well as a gas tank full of sludge from sitting for 15 years that keeps plugging up the fuel system!  
A little help... 'cause we don't all have to learn the hard way!

Well yes Barney I have not purchased anything for this build yet im still doing research and trying to make some good choices.  I was going to hopefully get the motor built by summer so I can work on it without having to drive it at all and with warm weather.  The only thing about using a 69-73 motor is that I will have to take it to get inspected and in Nevada in order to have a street legal swap the vin numbers must be from the same year car or newer, which is devastating I know, and at the moment im a 20yr old kid with no other transportation which puts me between a rock and a hard place.  Your build with the older 400 heads and the .050 lift and 200-215 dur with an 068 cam sounds great though, maybe if I can just get a 78 or newer block then that will eliminate my inspection worries.  Its a shame because my car is registered as a classic rod which means if I drive it less than 2500miles a year I can be exempt from smog inspections completely, but of course I average around 10k a year..darn it! Of course I would need another vehicle then, but then I could just run straight pipes with any motor I want! oh well though.
WOW 15 second quarter mile??? My friends would crap themselves!! Ha im getting really excited about this now I had no idea the 350's were so capable!
On the exhaust would it work if I got a dual exhaust kit for a camaro because I have had a hard time finding a kit for my bird specifically and at a good price.
I took a look at your formula and thats a very beautiful car you got!  Is that the original paint?  That car is a really great find in that condition how much did it set you back?

Barney would you like me to take some picture of my cars v6 so you can get an idea of how its setup?  Maybe this will make it easier to make sure im not missing anything.  

Alright, well im thinking maybe the best route to go would be like you said build up an older v8 myself or maybe just buy a crate motor if I can find one with similar specs to your build at a decent price.

My budget as of now (will grow more over the monthes) is around 1500-2500 to give you a price range, which should be enough to complete this, and if not I can always save more.

As always Barney your help is priceless to me.  I went to summit racing to ask some questions, and all these idiots could tell me to do was to build a chevy 350 and spend nearly my whole budget on some alumminum heads!  They didnt understand why I was so mad when I told them you need Poncho power in your Pontiac!  haha anyway Thank you Barney and I wish the best for you an your pretty formula and happy holidays!!

P.S.  One more question, do you know of any kind of  manual or something that would help me with setting up the timing for the cam and crank and other tedious things like this?  I helped my friend build up his pontiac 400 a few years back and I remember this was the most difficult thing to do and we were lucky we had a guy who knew all this stuff helping us, sadly I no longer have contact with them.  Also things like tourque specs and clearance and such would be helpful a booklet or manual with this info would be really helpful, dont want detonation on my first fire up!  

Alexx, since you have not yet purchased anything and you are on a budget with restrictions for inspection, my best advice to you would be to find a wrecked or rotten (harder in Nevada than here in Canada I'm sure!) 78 TA with a 400 (try to find a 4-speed car if you can!) and swap in the entire drivetrain. You will double your torque without any engine mods (over the V6). It should be easy enough to find a donor car, then you will have everything you need and stay within your budget, then upgrade later as money allows.
Jim Hand's book is great for all the info you want.
http://www.pontiacstreetperformance.com/ This site has his book available though you can probably order it through any book store.
My Formula was painted once in '88 or '89 before the original owner blew up the 301 and parked it. Other than a couple of dings and scratches it got when parked in his garage for 15 years and two big scratches that the guys who cobbled up the 454 left in the hood, the paint is really nice. It is the original paint scheme and I plan to touch up and color sand and buff the whole car this spring.
I paid $4000 for the car last year and made back $1150 of it when I sold the 454 and Chevy pattern th400 trans. But I'm back up to about $5500 invested. Here in Canada (Ontario) these cars are getting hard to find in wrecking yards because they get so rusty from the winter road salt, then they get crushed. Luckily a friend of mine has a wrecking yard that doesn't crush anything older than about '85. Still I had to pick through 7 or 8 cars to get all the stuff to put my car back to Pontiac power.
Gotta go, it's Christmas morning and the kids are getting up! Merry Xmas and I'll talk to you later.  
A little help... 'cause we don't all have to learn the hard way!

Merry Christmas Barney!!!

Ok that sounds great and believe it or not I already own Jim Hand's "How to Build High Performance Pontiac v8's" so that is one thing covered.  Thats actually not a bad idea, I just gotta find me a 78 trans am now which shouldnt be too hard as I have seen a few for sale in my area before and I can maybe be able to scrap the exhaust too.  Even a 79 would do just fine for me I will keep my eye out.

My dad loves your car and he is an old muscle car fanatic he actually used to own one in highschool, or so he says haha it seems like he used to own every type of car once in his life.  He owns a 69 Firebird that he wont let me drive so he appreciated these 2nd gen birds very well.

Love it and good luck, and a merry Christmas to you Barn hopefully I got a new repair manual for my firebird for Christmas.

-Alexx  

Alexx,

I have a set of 6X heads from a 1975 400 with a three angle valve job and new springs. If you are interested let me know.

Jose  

Hey Alex, i'm in the same boat as you, almost.  I'm 19 and have a tight budget too.  I have a 1970 Pontiac Firebird project car that i'm currently working on.  The car has a 70 350 block and is completely stock except for a hi-po cam and 4 barrel intake and carb.  I can tell ya if you get the 350, a stock 4 barrel intake w/ a carb besides a rochester will not clear your stock hood (mine didn't with an edlebrock carb but I also got the ram air, same hood just mine has gaping nostrils lol).  The engine runs a compression ratio of 8:1 which maybe ideal to everyday driving, but for me, I want something that will beat LT-1's and LS-1's as mine is only a weekend driver.  I think I will take barney's advice and just get early 400 heads along with some hi-po headers.  Good luck with your car alex, this article helped me alot! Thank you. So i'm guessing 400 heads will bolt up to a 350?  

Yes, the early 400 heads (67-70) should bolt-up no problem and you can check combustion chamber sizes and figure out the compression ratio at the Wallace Racing website, lots of great info there.  
A little help... 'cause we don't all have to learn the hard way!

Well ok I made an ass load of progress.

I purchased a Pontiac 350 5.7l V8, 4 bolt main, ATK reman short block, mostly stock I ordered it online for a total of $1950, came with everything short of intake manifold, carb, exaust manifolds, and heads.  

I scored a pair of nice 6x-4 heads with correct die markings!  I havent bolted them on yet but they just got back from the machine shop, they are looking freaking beautiful, got a valve job, new valves, springs and rockers.  Just painted them up today, still need a gasket set too, oh yeah and bolts.

Everything is looking good so far, I still need to figure out what i'm gonna do with the exaust.  I need some mounts, a radiator, alternator, ignition, wires, a carb, intake manifold, fan shroud, starter.  Then I need to pray everything goes right for me, so far i been lucky but replacing the rear leafs proved to be a week long task for me so who knows how this will go.

I figure i'm about $1000 away from finishing the motor and then probably a month to swap it out and get it running, but man am I going to be a happy son of a gun.  I think im gonna replace heater blower, and the entire power steering setup, and possibly rebuild the front end suspension, set it up with some new springs shocks and bushings.

Hey Jose do you still have those heads?  I have a buddy who is looking for some as well so e-mail me at sk8er0270@yahoo.com if you still got em.

Thanks  

Alexx, glad to hear you're making progress, remember when you install the intake that you have to tighten the bolt that goes thru the tming cover and water pump before you tighten the manifold bolts or you will break it. Don't worry about how long things take, I took my gastank and springs out in January, they're still on the floor!
Later, Steve  
A little help... 'cause we don't all have to learn the hard way!