Amarion58

I got a 84 Delta 88 with a 307 it running good so far but I want a little more power from my so I want to swap to an olds 350 but don't know where to start beside getting a 350. I need advice on what to do to get it in and started up.

Amarion58

I got a 84 Delta 88 with a 307 it running good so far but I want a little more power from my so I want to swap to an olds 350 but don't know where to start beside getting a 350. I need advice on what to do to get it in and started up.

joe_padavano

Welcome. I merged your identical threads.

The Olds 350 is externally identical to the 307, and was even factory installed in these cars for the 1977-1980 model years. Simply remove the 307, transfer everything to the 350 (brackets, mounts, etc) and bolt the 350 in. Note that you need to be sure use the 307 water pump on the 350 to match the 350 accessory brackets.

I assume you plan to delete the computer controlled carb with this swap. If so, you'll obviously need a non-computerized carb and distributor (be sure the distributor has a vacuum advance canister). Note that if you do delete the computer, you'll lose the converter lockup function for the transmission, so you may want to install an alternate system (or a toggle switch).

BillK

Should be a very simple swap but personally I would keep the electronic Q-jet and everything else from the 307 but that's just me. I prefer to keep everything working as intended. Also if you have emissions testing where you live there is a better chance of it passing.

olds 307 and 403

Joe's advice is bang on as usual. You can keep the carb and distributor if you stay mild. If you don't have emissions or under hood inspections, dump the air pump and plug where it goes into the cat. In fact install dual exhaust and eliminate the cross over, there is a manifold cap available. The 73 to 80, 77-80 especially is only a small upgrade for your non swirl port 307. An early low compression core, around 9 to 1 that is in decent shape may be tough to find being 50 years old. If you can find one, a mild cam and timing set would be a starting point. I still find good 73-76 engines around here, remove the number 8 heads and find 3 through 7a 330 and early 350 heads with .028" Rocket racing head gaskets will give 9 to 1 compression with 64 cc chambers, most will require milling to reach that cc, may as well do a valve job, guides etc as well. Add either something like a Lunati high efficiency series 207/207 .461/.461 112 LSA or something custom that is computer friendly. All depends what you are looking for.

Oldcoyote

I swapped a 403 for my computer-controlled 307 and kept the computer. Cam was a mild 206/206 at .050. Could not get it to run well.

Changed distributor to Performance Distributors HEI and a non-computer quadrajet. Problems solved.

Used a non-lockup torque converter.

Later, changed to a "better" cam 216/226 at .050 on a 110. Also used a "Stage 2" Qjet. This passed Georgia emissions (with cats) for many years. Required temporary tweaking of carb and distributor and "heating up" engine.

You could probably get the computer to work on a bigger engine if this was your purpose in life.

joe_padavano

The CCC system only controls metering on the primary side. People have successfully used it on 455s. You do need to burn a new PROM to change the advance curve, and obviously you need to change the secondary metering rods to match the engine. Frankly not worth it unless your local emissions testing conducts a visual inspection and they know enough to look for this.

olds 307 and 403

If he dropped a 73-80 Olds 350 with the stock prom it would probably run fine with minor tweaks. It helps not having the swirl port timing curve, which is a lot. The earlier motors ran 10 degrees less I believe. I think more guys have success using the Hurst/Olds or 442 having a richer calibration. If you find a complete 350, use the carb and distributor off it, if don't want the hassle. I am sure glad most of our 80's cars didn't have the CCC but we gained the sbc in in our Olds G bodies from the factory.