naminator

Hello folks. I am the recent owner of a 1978 Pontiac Grand Prix that received an Oldsmobile 307 swap. Here are the picks of the engine bay https://imgur.com/a/17SAjsZ (these are before, I am in process of heavily cleaning the engine bay and replacing missing stuff).

Currently I know a few things are wrong. First off, it is spraying/leaking oil from somewhere, likely the valve cover gaskets, so those will be replaced. The AC compressor is fully missing, so I am scouring junk yards for those, which I have found on some other cars, but I am unsure if they are the right models. The trans pan is leaking and the car is not happy running. According to the previous owner, all the plugs/wires are brand new, which when I pulled the driver side confirmed they had not been run, however after I sorted the now run condition and the car was idled for about 5-10 minutes total over a few tests, the drivers came out incredibly fouled, 4 and 2 looked very clean, 6 was a bit fouled and oily, 8 has corrosion on the exterior and looked very fouled and oily (maybe it wasn't replace as it is a pain in the ***). I am sure it has a vacuum leak, so I picked up a Haynes manual to try and get some direction, which actually has helped with a few things. The previous owner had replaced the plugs with new NGK ones and the wires, but I am going to pull the plugs and replace them with some ACDelco's, make sure the wires are properly run etc. The distributor is an ACDelco but the contacts inside the cap look a bit chewed(?) up if that makes sense. That is on the ever growing list. The fuel lines are knocking on deaths door, between dry rot and being swollen, so those are going to be replaced with temporary rubber lines.

Anyways, Saturday I had checked the plugs, cleaned them off a bit, then did a test. She fires right up every time with no fight and idles a bit rough. Without the air cleaner she does better (another thing on the list) but when I put the cleaner back on she continued to idle ok. The difference was revving the engine. I gave it some gas from inside, she protested when revving up and then when I let off she bogged and died. When I cranked it again, for the first time since she was properly starting, she took a bit longer cranking and really fought me. I figure the cleaner is choking off the fuel supply by resting on an already bad line or it is not letting air through. Since my distributor has vacuum advance and it probably hasn't had proper timing set in some time, I was planning on doing a bunch of things, but the vacuum system is where I am stumped. The Haynes manual I have is pretty generic, so it helps, but I feel like I need a service manual for a 78 Grand Prix SJ, one for whatever this motor came out of and 1 for the edelbrock carb to try and piece them all together. Any help or direction or suggestions on what to look for would be amazing.

I know the kick down isn't hooked up, and it is also really badly frayed so that needs to be replace, the air cleaner was flattening the fuel line into the Edelbrock carb, which was heavily corroded and gummed up (marvel miracle oil and carb cleaner freed that up a bit) the gas in the tank is over a year old, but I did toss a new filter onto it, the old filter wasn't terrible and I haven't seen any chunky bits in the filter so far. I will completely drain the tank and add some fresh stuff when I get a chance, but at half a tank in it, that is a pain.

Oh and in the pictures, my finger is on the "1" position for the rotor/wire for this installation on the distributor.

oddball

Well, the 307 isn't exactly an inspiring engine, and there's lots of hacking to mash things together. Honestly, it's probably best to keep an eye out for a better engine.
Your biggest challenge will be figuring out part numbers for the parts store guys. Someone on here can probably tell you roughly what year the engine is, then you can pick some random Olds from those years that came with a 307.
The location of #1 on the distributor doesn't really matter, as long as the wires are in sequence and you know what's going on.
Those 90 degree boots on the plug wires aren't helping. Straight boots are best with Olds iron heads. It's hard to get the 90's on, and if they are all the way on then they'll just melt against the manifolds.
I'd recommend going ahead and getting a new cap and rotor. HEI caps and rotors are pretty universal, so you can reuse them later.
NGK plugs are good, no particular need to go with AC Delco. Get whatever is convenient. I used AC Delco for the longest time just because I had the part number memorized.
The carb probably needs cleaning and a rebuild kit. That's a pretty recent Edelbrock so it should be easy to get a kit.

Is that fitting on the intake manifold, right in front of the distributor, plugged? A little hard to tell from the pictures. That's normally the port used for the brake booster, instead of running a long line over to the front of the carb. It would certainly be a huge leak if it's open.

Depending on where you live you may be able to get rid of some of the emissions equipment, like the smog pump.

Probably go ahead and get a new air filter.

IMO, when dealing with a mashup like this, start by removing *every* vacuum line and plugging everything. Get it running well, then start slowly adding things back on. You can make your own setup with whatever parts and systems you actually want.

edzolz

Is this 5A block even a 307? My 85 442 I purchased new had a 307 that had 5.0 casting numbers on the shelf behind the water pump. I do not know what casting the 403's were.

naminator

Yeah I know it isn't a great motor. Unfortunately I have no garage, no real drive way and limited space. That means I am 100% not able to do an engine swap, and even if I was, my wife let me buy one weird old BOP car, 2 would probably end poorly. If I had a nice 2 car garage and extra parking? I would 100% go down the 455 big block route, gut the interior, do tons of body work, paint it a white color, new rims/tires and really create what I think is an amazing looking car. But like I said, no room, limited tools and this is all rather new to me.

I know the location of #1 wire doesn't matter and yes, the firing order is correct. The 90 degree boots are indeed a massive pain, and while I wasn't planning on swapping them, I was planning on re-installing all the wires properly. Some straight boots will go on the list. As for the distributor, the cap is rough and I didn't look at the points/rotor closely, so that should probably be switch. The only reason I was planning on swapping plugs is the previous owner said they where brand new, and the drivers side did look new, but the passenger bank like I said, did not. He could have easily neglected to change 2 plugs or more, so better safe than sorry in my opinion.

I have already found the re-build kit online, but hadn't grabbed it yet. It definitely needs it though. That fitting in front of the distributor? I have no idea. I had yet to check it and will if I start it tonight. As for emissions, there is no smog testing here, so I can rip ALL that stuff out and not worry. The safety inspections are fairly lax here thankfully and I am hoping that I can get the GP limping along to an inspection facility. This is more of a rescue project that I will work on, but I need that inspection, since if it is safety inspected or close to it, I can then list the car for sale and work on it while increasing the price. My goal is really to fix it then flip it, then pickup the next restoration project/fun thing.

That air filter is trash, I knew it was trash and I am going to replace it. However I don't know which model/setup to get, since it is pressing on the fuel line into the carb and I have heard the choke will rub on them. I need to take the time to sit down and figure that piece out.

As for the vacuum lines, I appreciate that suggestion regarding removing/plugging and testing. I have been chasing little things all over the engine bay (and cleaning) but my struggle is to know what is mandatory to leave one, what can come off, where to plug things etc. Maybe you can see it, but there is just loose random crap everywhere on this engine. It is like someone put some serious work into this, got 75% done, ran out of money/time and just finished it there and then moved it down the line. Supposedly I am the 4th owner since the Engine swap happened, previous owner had it since 2019, the guy before that, I have no idea. Ideally, I could get the engine sorted and running well, brakes, AC, heating and cruise control. If I could get it to "semi reliable running cruiser" and it retains its current mean sounding noises, I would be over the moon.


Yes it is a 5A block. The casting on the shelf behind the water pump is 3161-5A, which sets it as an 81+ 307. With the limited knowledge I have been gathering, I still have yet to determine if it is a Vin Y or Vin 9 block. Honestly, the previous owner had painfully little information to give. However the mystery keeps getting deeper and deeper. Between the "performance" carb, the straight piped then un straight piped dual exhaust, the hacked together remains of a very expensive custom sound systems and what is a custom paint job, the plot thickens daily. Recently I was fighting an ant colony in my driveway behind to car to try and photograph the diff and it appears to be an 8.5" rear end, although some said it was likely a 7.5 (except according to the identification pics it is an 8.5"). If it was, it continues to push the idea that someone at some point bought a 78 GP SJ and put a 307 Vin 9 motor, trans and diff in it for reasons. The engine has been apart several times it appears, which could mean at some point it had a bunch of work done to make it more powerful, or maybe it is just a boat anchor. This weekend I am planning on changing some fluids and hopefully fix a blown brake line in the front to try and get this thing moving at least down the block, then I can work on more identification.

oddball

You can always do simple things for the time being, like get a cheap-o chrome air cleaner from the parts store. Might need a flat base, if there's enough room under the hood. Most of the drop base air cleaners have two big notches to make room for fuel fittings like that.

When I've had problems like that - car runs just fine, shut it off for a bit then fire back up and it's junk - it's been something in the carb sticking because it's gunked up or bent. Something may work fine when cold, then once there's some heat everything moves and it doesn't work. Pay close attention to the throttle blades and make sure they're returning all the way closed when you let off the throttle.

And that's a manual choke. So you're opening the choke once it's warm, right? just checking...

As far as what's necessary?
radiator hoses (you can cap off the ports on the engine heading to/from the heater)
fuel line
IGN power to the distributor
choke and throttle cables
brake booster vacuum line
starter wires

Check and double check that the ignition timing is correct and you get a good, reliable spark. A good timing light really helps. One very correct statement is "90% of all carb problems are ignition problems". That's an HEI, so no points. But, there are batches of bad modules that cause intermittent spark.

From there, you'll probably want to add the vacuum advance back to the distributor - that can be ported or manifold, depending on what the engine likes. Adding a PCV would probably be a good idea if it's a driver.

Getting A/C to work well can be very, very difficult. First problem will be figuring out what compressor those brackets support. I *assume* it's an R4, but I'm not familiar enough with that generation of stuff. I used junkyard parts for mockup - figuring out what fits and whatnot - then bought new replacements. There's a lot of equipment and whatnot involved in A/C, so might need to hand it to a shop once you have the compressor figured out, installed and wired.

The 307 is the black sheep of the Olds family (in today's environment). It's really hard to get good output from one of those. But, it can also be a fairly efficient and reliable driver. There should be giant "307" letters cast into each side of the block.

naminator

The air cleaner on it is a drop base cheap-o chrome model. It has the cutouts, but they aren't enough clearance. I was looking at spacers and/or a different cleaner. I uh... Definitely didn't open the manual choke when it warmed up, which may explain things. The blades in the carb, especially the choke, where pretty stiff when I got the car and the bowls where bone try and everything had this white crusty powder on it. I assume it is oxidizing zync from crap ethanol blended fuel sitting in it for a while. I have avoided running the car for any real length of time as the gas is not the best in the tank, the oil is pretty much shot and has gas in it (no water or glitter) and the coolant it probably old. A full coolant flush will be happening asap, along with oil and trans fluid, maybe the diff oil. This is stuff I am fairly comfortable doing myself.

The ignition timing is likely off. I have been putting off picking up a timing light, but I guess it is time. Hopefully I can make that all work properly. The Distributor has the Vacuum advance hooked up. As for the AC, everything is "there" the only missing thing is the compressor and some of the hoses/fittings look to have been twisted or busted. I have found a couple donner junkyard compressors, just gotta figure out which one will fit. If the compressor is hooked up and does even a little bit, I know the basics of how it works and how to diagnose using fluorescent dye to track leaks etc.

As for the 307 being a dog? Yeah I know. But that is pretty much any small block from 78-88. I love the look of them, I love how throaty it sounds idling and even if my 8 year old FWD Taurus would blow the doors off it, something about the G-Body tickles the lizard parts of my brain in a way a modern car doesn't. If I had the money the project would be very different, I am just doing this cheap to get the experience and gain some knowledge. For $1000 to have it on my drive way with surprisingly solid frame/metal and a poorly running 307? I could part it out today then junk the rest and make everything I have into the car, parts and probably all the tools I keep picking up and then some extra for a cold beer and a steak dinner.

Unfortunately it went from living next to hells exhaust port with the heat/smoke to cold and raining. If the weather holds tonight, I will probably start it up and spray some brake clean around the base of the carb and see if there is a leak there or in other spots, if it heats up I may change the oil/filter, see if I can find a better air cleaner, maybe hook up my new fuel lines and potentially I will change the plugs/wires, if I get to the part store.

oddball

I'll admit, the manual choke is an odd choice. I guess whoever bought the carb just wanted to save $20? Should be a cable poking out under the dash somewhere.

Yeah, gotta give the carb a thorough cleaning. Get a bucket of Chem Dip at the parts store and soak everything. Wear very good and thick gloves! That stuff burns. The carb body won't fit in the can (I keep 3 gallons on hand and use a 5 gallon bucket for carbs....), but you can set the carb on top of the can and use a brush or cup and keep wiping/soaking the carb body.
That stuff is seriously caustic, so use caution. Rinse with water.

A/C is a real beast. Using a junkyard compressor is very risky. The internals of the A/C system must be pristine. Any contamination will cause the compressor to fail, then it will send shrapnel through the system which will then kill any future compressor. Junkyard compressors are almost always exposed to the elements, so the internals are all messed up.
The condensor, expansion tank and evaporator need to be flushed since it's been sitting open and uncapped. The lines probably need to be replaced. Local A/C shops can replace the rubber, usually ~$40-$60 per line.
The A/C system has to be evacuated to a near perfect vacuum before filling with refrigerant. There are "vacuum pumps" that are just a venturi that runs off a compressed air source. They kinda-sorta work, but make a ton of noise and the compressor has to be quite large. Those don't draw nearly as much vacuum as a real vacuum pump.
You really need to use a manifold gauge set to charge the system. It's very tough to get the weight correct if using the little cans.

I'd recommend siphoning out what you can from the tank, then dumping in some fresh gas with some sta-bil or something. Go full Roadkill and put two or three fuel filters in-line.

naminator

Yup there is a choke cable, which barely moves, taped to the bottom of the dash.... I wonder if I can get a conversion kit for this thing to have an electric choke. I plan on cleaning the carb after I start it up and check for vacuum leaks, I also picked up a vacuum black of cap kit thing, some 10w30, a wix 51258 and some new, AC Delco R45TS whatever plugs for it, since I don't trust all the NGK's plugs where replaced at the same time. I am going to pull off the existing plug wires, leave the current plugs in and use them to stop and cleaning agents since it is just caked thick with oil around those holes.

So on the list right now, clean, clean some more, clean even more, replace plugs, wires, fuel lines, change the oil/filter, block off any vacuum leaks and test. Then I will fix the vacuum issues, work on timing and once I am confident it is running smooth, I am going to rebuild the carb. Thanks for the tip on the Chem Dip, I was seeing so many different options for cleaning the carb. I will probably order brake and fuel line online, along with a tube bender and a flaring tool, to at least fix the brakes and potentially re-route the driver side fuel lines to the passenger side where the fuel pump actually is.

As for the AC, that really is disappointing news. I will have to look into what options I have for that, since I would like to have AC, but it is a comfort to me, much like the stereo, so I am not too torn up about that. Lots of other little things to do first.

oddball

You can definitely convert to an electric choke. Then just run an IGN wire to that terminal. Just note that the choke coil can pull quite a bit of current, so don't necessarily want to use the same wire as the one that's feeding the distributor. There's usually a spare terminal on the fuse block on the inside you can use. Looks like Edelbrock part #1478. They want a pretty penny for it....

It's probably best to clean the carb *first*. A gunked up carb will not clean itself, and might just get chunks of corrosion wedged even deeper into the carb. Sticking parts will cause it to run poorly, even at idle. Soak stuff in Chem Dip, then use several cans of Carb Cleaner to finish the job. Wear eye protection!!! The carb cleaner and brake cleaner at Walmart is extremely cheap and just as good as the other stuff. They run out a lot because **some people** (like me) buy entire trays at a time.

Yeah, cleaning is fun.... If possible, get a pressure washer to help. The only thing you need to be particularly careful of is the alternator and distributor. Cover then with a plastic bag or something. And, of course, cover the carb.
Use lots of compressed air to get all the water and leftover gunk out of the spark plug wells before removing the plugs!!

You probably do not need to replace the brake lines. Just a good flush with fresh fluid should be enough. You can rent a flare tool from the parts store. It's a piece of junk, but all of them are junk until you spend over $100. Just make sure to get soft tubes - e.g. nicopp, definitely not stainless - and those cheap tools work just fine.

For the fuel line or anything else that's lower pressure where you're going from metal to rubber, you can use the first operation of a dual flare to create a bubble on the end of the tube. That gives the rubber hose a good lip to grab. Never just slip rubber onto the end of a smooth tube. It *will* come off, sooner or later, no matter how tight the clamp is.

naminator

I have to say I really appreciate the tips and suggestions, it is giving me a ton of help. I spoke with Edelbrock yesterday and they said they don't recommend switching the 1905 to electric choke with the #1478 kit, since it requires swapping secondary's or something. Honestly for that price, I could buy an AVS2 1906 "parts" core from ebay anyways, so manual choke it is I guess. I did find the rebuild, tune up, banjo fitting and all the other little extras thanks to edelbrock, so that was a nice surprise. I will be absolutely cleaning the carb out with chem dip/Canadian equivalent and carb cleaner, then, depending on condition, doing a rebuild and a tune up on it.

For the brake line, on line is blown right through and the other ones are looking a bit rough, so I am going with better safe than sorry and replacing anything I don't fully trust, much like the fuel line. With cleaning out the engine bay, I was using Spray Nine and my decidedly whimpy electric pressure washer, covering the carb with bags. The distributer and alternator I left uncovered, because they where also filthy, but I used a much more gently weed sprayer to attempt to clean those parts even a little bit.

oddball

OK, The brushes on the alternator, the slip ring, and the bearings can get goobered up from washing but it's easy to tell. It'll either not work and/or squeal like a pig. Parts store replacements aren't that expensive and tend to work just fine.
For the distributor, take off the cap and rotor and make sure everything is clean and dry. Some rust on the reluctor is OK, but the module's contacts - 2 on each side - need to be good.

That's a bummer on the lines. I like nicopp because it's super soft so it's easy to bend and flare. Those lines are copper colored. You can also get coated steel, which normally looks green, at the parts store. I'm not sure which would hold up better to that Up North environment. Nicopp gets pretty expensive, too. Stainless lasts forever but it's a nightmare to work with - even the "perfect fit" replacements.