Olds 307 to Olds 403 engine swap info please?

Just had a HOT (96-degrees here today) but happy drive in my Cutlass! IT IS ALIVE again....only took....well...a year....

Pics below....please understand I've not so much as wiped off the air cleaner yet. Will be cleaning and detailing under the hood this weekend...but after a year, figured it was time for pics!

So here we go. Neil gave me a good walk-through of what he did. ECM and wiring are in a pile in the trunk. You can SEE the engine under the hood now!
It runs, idles and drives GREAT. Much more power than the 307. Still not a monster, but the single exhaust and rear gearing suck. Will fix those soon!
He showed me the old distributor...and it was shot. Weights stuck. My fault, tried to go with used parts. New distritutor is in. Timing is set at 12 and advances to around 28. No ping, no hesitation. Starts easy, even hot.

Cruise control arm modded and and mounted to new carb. Wiring modded to work without the computer. Works like new. Set cruise at 70mph....holds fine!


Check engine light is out FOREVER!

A/C wiring fixed, and blower works again. Had a short in the blower switch, that's fixed too. Compressor is cycling...needs a charge, still R12. Will charge shortly. Does cool, but not COLD like it needs to be. Wiring done, and I can do the rest!
He also re-gapped the spark plugs. I put new 71 Olds 350 plugs in, gapped to the '71 specs I found, and he said they needed a bigger gap with the electronic ignition.
Lastly he tightened up the thermostat housing....I didn't have it tight and it was seeping, and replaced the lower radiator hose, which had a pinhole in it. I missed that as well.

Only a couple of outstanding issues (beyond how dirty the engine bay still is). I still have to order a lockup kit for the 200R4 transmission, so driving home I had to keep it in 3rd gear, and the other issue is it ran a bit hot going down the road. Averaged 220-240, and I know I have a 195 thermostat in it, and it has a new water pump. With the 307 it never went up to even halfway on the gauge. Was too hot to check the coolant when I got home. I hope it's just not topped off. Will check tonight.

Here's some pics!

On the road again!




Nasty old 307


Plan A. 350 installed....trying to keep the 307's carburetor, ECM computer, wiring, hoses and smog stuff. Ran like garbage, could not see the engine for all the hoses and crap. FAIL!!! Yanked it all off.


Plan B. 1971 Rocket 350 installed, NO computer/hose mess anymore, new Edelbrock carb and vaccum distributor. You can now SEE the new engine!



Old '88 307 at idle, in gear. No oil pressure


New 71 350, Oil pressure at idle in gear


Old 88 307 oil pressure while driving


New 71 350, Oil pressure while driving


Next pics will be after underhood cleanup and detailing.

-Mike

 

You need to keep that mechanic. Seems like a real good one.

 

I just got back from the friday night fireworks at the Dell Diamond ballpark. Dad showed up, and we took my 3yr old. Took the t-tops off the Cutlass and parked way at the back of the parking lot, right on the edge of the field where they shoot them. Got a great show through the t-tops!! Man I missed this car!

That said, the idle is still a little low...feels almost like it's going to stall when stopped in traffic waiting to get out after the show. Never did stall, but felt close. Also, I checked the coolant and it wasn't low. Tonight it never got up above about 210 on the gauge....but it is nighttime.

Dad was impressed with it. I got on it just a bit coming back and it sure has more power than it did. It still has the stock 307 single exhaust....only mod was 403 manifolds. It's so quiet you almost can't hear it running. I also think the cat converter may be a little plugged. Will fix that soon.

Still have some tweaking to do but I'm tickled it's back on the road!

-Mike

 

What temp sending unit is being used? Perhaps the one from the 307 is different than the 403?

Glad you are happy. Bump the idle up a notch and have a great weekend with the car and family.

 

I used the temp sensor from the 307. Just moved it over to the new 350. Maybe there is still some air in the system...?

 

I don't know about the air in the system. I've not had that problem. Do you have an extra temp gauge laying around you could hook up under the hood just to see if the gauge in the car is reading accurate?

 

No, but that's not a bad idea. It never got close to overheating today, but seeing it over the halfway mark on the gauge was new. It never got that high with the 307....but I guess the 350 may run hotter.

We'll see. This was the first day back on the road after a year of fiddling with this swap. Still sorting it out.

 

Glad you got it back and are enjoying it. I've been enjoying reading the saga as it has been unfolding.

 

Mike must be out enjoying that Cutlass?? Wonder if'n he got it to run a little cooler?

 

That 350 will run hotter than the 307 and if it was a 455 it would run even hotter.

 

That's prolly true if he's still got the original 307 rad in there. Maybe some water wetter might be in order for a little extra cooling power in the Texas summer heat?

 

Took the car to the Cedar Park cruise-in tonight (pics in the Events section) and the gauge never got hot, stayed around 180-205.....good deal! Guess it just has some air in the system that had to work itself out. Will check the level tomorrow.

Car is running GREAT! I can't believe Olds never offered the 350 in these....307's were junk....this has SO much more power and since you don't have to floor it to make it go, I bet the mileage is ok too! We'll see!

-Mike

 

Cool beans Mike, glad its working out good.

 

SO I sold Misty's Grand Prix, but we've not bought her a new car yet. She's driving my Ram, and I'm actually commuting to work in my Cutlass. Never planned on that. Had to strap the kid seat in the back so I can drop off at daycare...looks funny in that car.

I re-charged the a/c Monday....man R12 is EXPENSIVE now, but it's blowing cold. I also got a big piece of cardboard and made me some t-top shades. Painted them silver on one side to reflect the heat and flat black on the bottom, which is what you see in the car. I need to get some REAL ones made out of headliner material, but for now, this works.

You’d be amazed what a difference the t-top shades made in the Cutlass! It's dark in there! It can now actually be used in the summertime in Texas...like a real car! Ha! Before it was like sitting under sunglasses, you just baked, and the a/c had no hope of keeping up in the afternoon. I ran errends after work in it yesterday, and after running it just a bit, it cooled down nicely inside. Wild!

The vents by the gauge cluster blow pretty strong….enough so that you can feel the a/c on your face. The long passenger side vent above the glove box though has almost no pressure. I opened the glove box door and dropped it down, and there is a bad seal or something in the ductwork in there. The INSIDE of the dashboard is getting all the a/c on that side...I could chill Cokes inside the glove box. Will see if I can sort that out this weekend.

In other news, the car is going to Taylor Muffler on Monday. Sadly, the new hippy tree-hugger law here requires a catalytic converter on vehicles 1983 and newer, even though after 25 years they no longer do the smog test itself. SO I’m getting a free-flow cat installed, than a Y-pipe to dual turbo mufflers, and dual pipes with chrome tips exiting behind the rear wheels, 80’s 442/Grand National style. Even though it will not be true duals, I bet it’ll sound a lot better.

Also, I changed the oil to Exxon high-mileage 10W30...which I'm told has more zinc in it for flat-tappet engines. Seems to run fine but plan to keep the oil changed often.

Coming along!

-Mike

 

Nice, Mike!

I love moonroofs. T-tops, not so much. Had them only in the wife's '85 Nissan 300ZX, as those cars pretty much came stock with them (look around - it's rare to see a 300ZX with a plain roof). Around southern California, they were OK when the weather was cloudy or rainy, but as you found out, you really need those shade panels on sunny days. As I recall, we only had them completely off for a drive just once. Lots of wind buffeting - not pleasant. Our next vehicle has a moonroof.