mother$hip89

I have been using an old school hei distributor and quadrajet on my olds 350. However, I have the computer controlled qjet that came with the car's old 307, the ECU is still in, and I could get a computer controlled distributor from a wrecking yard. What system would I be better off going with.

olds 307 and 403

What year 350? What year car? The later computer carb timing curves were very aggressive and calibrated lean. On a low compression late 70's 350, it should work OK but may be too lean. Many have adapted the CCC to larger engines but many of those are richer calibrated Hurst/Olds and 442 set ups.

mother$hip89

The car's an 89 Cadillac and the engine's a 74 350. I figured it'd want to run lean being meant for a 307.

joe_padavano

The ECU from a 1980s 307 is pretty dumb and only has a very limited range of control. It controls the primary side mixture on the Qjet (secondaries are still fully mechanical mixture control), timing, EFE valve, vacuum break, and emissions related functions like EGR valve, evap canister purge, and idle speed kicker for A/C. It also controls converter lockup.

You won't see a difference with the primary mixture control. The timing advance curve cannot be changed unless you burn a new PROM, and it is set for emissions, not power. This is the biggest reason not to use the ECU on non-stock applications.

Joe King

I am doing the same swap on the same year Brougham but I am keeping the ccc. Hope to start yanking the motor Sunday and start marrying the 350 with the 200r4 early next week. I want my lock up tcc,. Ac and cruise control so I will be keeping the ccc.

I will let you know how it turns out if your interested.

If you don't mind me asking, what are you running for manifold/headers?

olds 307 and 403

With a 74 350, being 7.9 to 1 and tiny cam, it can tolerate the 60 degrees of timing that is programmed in. Just get the CK or CV secondary rods and a G hanger or it will be too lean on the secondary side. I believe the 89 should have a knock sensor in the side of the block. It needs to be torqued to 11 ft/lbs or it will read incorrectly.

mother$hip89

I'm running the 14 and 17 exhaust manifolds. Just remember whatever you use you want to keep the O2 sensor. I actually ran the car for a while with the stock computer carburetor but non computer hei and th350. It seemed to run ok but ran rich and mpg was terrible.

Joe King

weird, I finally pulled the motor out of my 89 and have the same manifold. My search for these as a pre-86 manifold.. I dunno what that's all about. I keep hearing about the post 85 307 having really bad flowing exhaust manifold and not sure if these are the. Either way I'm not worried anymore- I have a set of headers I am throwing on the new motor.

olds 307 and 403

If they are stainless steel tubular manifolds, they are junk. If they are cast iron, they are slightly less awful.

Joe King

I guess I have some slightly less awful manifold going in the scrap pile
All this time I was thinking they were the POOPOO manifold but really they were just the poo ones. I haven't read anything about them being used past 1985 so I guess that is what I wasnt expecting

olds 307 and 403

I also thought only the 442 had cast iron exhaust manifolds past 85. It is possible the original motor blew, more of the swirl port motors seem to die earlier than the pre 85 307. It probably because people wanted them to die. Did both have 7A heads 307's? It could be Olds was using whatever manifolds were left by 89.

Joe King

My Cadillac has 7A heads on it, maybe it was a Cadillac think to use the iron manifold.