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Pontiac

3K views 13 replies 7 participants last post by  xxx(madmax )xxx 
#1 ·
I have a 1977 Pontiac Firebird Formula 350 it has the 350 Pontiac engine.....not a chevy.....I was looking at a chevy engine to drop in ....my question is ... how hard would it be to drop that chevy engine into my car. Would i need to change the engine mounts and electrical system ...I do know that in 1978 the pontiac firebirds were changed to chevy 350s and the 1977 firebirds and 1978 firebirds are almost identical up to my knowledge.
I want to change because there is alot more aftermarket items I can get for the chevy then the pontiac....I have been looking it is hard to find high rise intakes ...specific cams ...blowers and superchargers...and just the ussual products which are very easy to get for a chevy..
If someone else has a better opinion please tell me because I really would love to keep a pontiac engine in a pontiac...
 
#2 ·
I have a '77 Trans Am with the same engine. Swapping the two is pretty simple, new motor mounts are needed, new tranny too unless you get an adapter from Jegs or summit. '77-'78 are exactly the same other than seats and the headlight bezles. '77 had the honeycomb bezles '78 had the hatch bezles. I'd stay with the pontiac 350, they are underrated. With some headwork to increase the compression you can double the HP. (stock HP is 170). The highrise intakes are out there, I'm building my own for a low RPM application, but the highrise high RPM intakes are out there. The parts may be more exspensive, but I've learned its worth it in the long run. If you need anymore help with the body or interior or any info on the swapable parts let me know, happy to help, just PM or e-mail me.

HK

[ December 03, 2002: Message edited by: Halloweenking ]</p>
 
#3 ·
Yeah, be different. I am building a 71 oldsmobile cutlass with a 400 pontiac motor. Just because that is what it has in it. I prefer not to follow the rest of the sheep out there. This is not to say the chevy is a bad motor, just that it is so common and boring. If I were to swap motors, I wouldn't go to a checy, I would either go with a bigger pontiac or perhaps put in a 500 caddy. The caddy would weigh close to the SBC with an aluminum intake.
 
#4 ·
They didn't change to a factory installed Chevy block until about 80 or 81. Pontiac used Pontiacs into 79 then changed over to Olds and Chevy. Most 79-80 Trans Ams came with the Olds 403.

As HK said the 350 is underrated. A good cam, can be purchased with lifters from Summit Racing in a set for $87. Part # 2801 or 2802 I think. Anyway there are lots of places to get parts for these old Ponchos. For street use you really don't want a "highrise" intake anyway.....loss of low end torque which these motors were built for. I recently saw an article on a 597HP Pontiac 350. Depending on the heads on the heads you may be able to bump up compression. Upping the compression, cleaning up the intake ports some, 3 angle valve job, good cam and an Edelbrock Performer RPM intake and you'll be looking at a very streetable 300+ hp motor.
 
#5 ·
Yes, the article was in car craft and the builder was Bruce Fulper. You can see his website at Pontiac Power.com. I agree, the Pontiac 350 is under rated. Get the compression up in the low to mid 9's, some port work, a cam, an edelbrock performer RPM intake, headers, and you'll have a good running street motor on 92 octane. Jim Butler Performance also has alot of parts and very reasonable pricing. He will also talk you through the buildup - he's a great source for info. Be original and keep the pontiac motor in the car, the right parts will put a smile on your face.
 
#6 ·
thanks for all your replies also I was wondering since I have the same block as a 400 and a 455 would it be possible to bore my 350 out to a 400 or even 455... and just buy new heads.I am just curious because I love big power and big bore....so if i were to do all this work on it if it were a 455 i could have I am guessing up to 400hp....I have already put headers on what a ***** those things are to put on ....and a full dual exhaust coming out the sides it is a 3 in to a 2 1/2 because I could not get the glasspacks on with three in but soon i may just get rid of the 2 1/2 and put three in full....I am a back yard mechanic and it was well worth it in the end ...with all the problem i have reached with doing this I really do want to keep my motor...
 
#7 ·
You CANNOT bore a 350 out to 455 specs. I just recently covered this in another thread. The blocks are the same outside dimensions and all heads are interchangable as the water holes and bolt holes are all in the same locations, BUT the internals are different. I believe the most you could ever go over on the cylinder wall of a 350 would be .120-.125, but it depends on the block. Sonic testing is required. You would have to go .276 over to get to the 4.151 bore of the 455. The water passages between the cylinders are NOT identical between blocks......AND the machining expense would be too great. If you want to throw money around buy an already built 400 or 455. To machine a 350 block to even .125 overbore will be expensive. In addition the 455 crank has 3" main journals where the 350 and 400 cranks only have 2.75" mains. You would have to have the Mains align bored and honed .25" whish would not be cheap, if even possible. I guess you could get a 455 crank turned down to 2.75 on the mains and stroke the 350, but you would never get it to be 455 cubic inches.
 
#8 ·
thanks for the advise it deffinately would be alot cheaper to just buy a 455 already assempled then do all that machining which would cost big bucks like you are saying .......also has anyone heard of any blowers for a 350 pontiac motor. The only blowers I have seen where for chevy, ford and hemis. I am so interested in this motor now and very curious of what I can get for it other then looking every day in summit for pontiac stuff which they dont have much of.I am also going to be looking at a chevy 400 motor that a friend of mine has and can get me a good deal for it ..I am new at the buying engines part so please be easy on me...he wants 400 dollars and he said it was bored 30 over,it is a 2 bolt main, it has vortec heads and it is fuel injecting he also said that it is pumping around 500 horses which I dont see possible I think I am rightesspecially since it has a 2 bolt main...but anyway he said it needs a cam, timing gears, a timing cover gaskets and rockers as I can remember...should I get it ....I am going to check it out also for cracks and stuff... but like i said I am new at looking at how good an engine is to buy ...thanks again for your time and in helping me out with my stupid problems.....
 
#10 ·
to answer your question I have a 2 1/2 in exhaust at the monment I wanted three mostly becuse I wanted to run the exhaust with out any reducers personal opinion bacically the headers them selves are three inch anyways so I always personally thought the faster the exhaust comes out the faster it can suck a new air/gas mixture in ....I am not just saying this but I have tried it a couple of time so it basicly like i said is personal choice...but keep me informed of some hints please.thanks

[ December 05, 2002: Message edited by: xxx(madmax )xxx ]</p>
 
#11 ·
I say Toss that Poncho 350 (right into the bed of my pick-up truck!!!) If you are planning on going "ALL OUT" blowers/high-rise etc.. Nothin beats a BigBlock Chevy. Nothing!!!!

The Best Bang for your Buck I ever got was slappin some older higher compression (72CC) ON A stock 400 (410 lift cam). Ran a 12.62 in a 75 firechicken. To go faster, that would have cost$$$$$$. I know what $ some of my budies have in there chevy's. Small Blocks Cost $$$$$ if you want them to rev.

Who needs a High reving small block on the street anyway? Its low Rpm Torque grunt thats going to win any street battles!!
(Race at your race track, not in our streets)
 
#12 ·
I did not really ever say I race on the street it is a street car yes but it will be raced at a local track ....when talking about all these mods I don't think i will make it from gas station to gas station hahahaha.I have a daily driver. I have always wanted a pro street car which I mean is a drag car that can drive on the road not race on them.I really am against street racing. There is no feeling then the feeling of being on the track. street racing is just not worth it. to many risks. :) and I forgot to add that I was thinking about a 454 bbc but they are very expensive and I dont know how well that would bolt up into my firebird.

[ December 05, 2002: Message edited by: xxx(madmax )xxx ]</p>
 
#13 ·
Oh ya, There are blowers out there for just about every single motor, Pontiacs alike. Contact the blower company you are interested in, they will tell you were to turn. Remember, the only diference between Chevy blower and a Pontiac is the intake manifold.
A buddy of mine welded up his own intake for a BBC Blower using an aftermarket intake as a base, worked great.
 
#14 ·
thanks I will look into that too this bulletin board I think I have learned more about certain things then hanging around some of the local mechanics. well I am still looking foward to at least do some things to my 350 pontiac and untill i get some more money I will go from here I think...next problem i think i will have will be the trans but that will be some other time because I think the stock th350 will be fine for now.
 
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