early engine in an 85

[celticsam]

I am looking at a 70 350 rocket engine to replace the very tired 307 in my 85 Salon. The dilemma is whether to try and keep the computer and swap out the secondary rods and hanger on the carb, or to eliminate the computer all together. Bearing in mind that I want to keep the stock gauges and AC functioning, I'm not sure of the best way to proceed. The AC goes through the computer as far as I know...not sure on the gauges...but I don't think the CCC can accommodate the 350... at least not properly. Asking those with the know-how...

Neil
Littlestown, PA

 

[BuickOldsPontiac]

The CCC and ECM can accommodate the 350 (and 403 if you'd like). I don't have the link handy on this computer (I'll look this evening), but it has been done successfully before. You would tune the secondaries on the carb just like any other. On the other hand you can keep the A/C, original gauges, and transmission lock-up and eliminate the computer as well.

I would general favor keeping it, but that depends on what you are planning for the car...

 

[celticsam]

I was leaning towards keeping it, but eliminating the AIR pump and injectors (using the 70 Cutlass manifolds currently on the engine). Plan was to paint the engine black rather than it's current gold. The engine was rebuilt 15Kish ago...stock rebuild, so no worries about it... I was just worried that the primary circuit on the carb would tend to run lean with the larger engine...or that the computer would not be able to adjust to the larger displacement...

Neil

 

[BuickOldsPontiac]

Here are the links:

http://www.robertpowersmotorsports.com/CCC.html
http://www.robertpowersmotorsports.com/G-bodyV6-V8.html

The first car listed is running an Olds 350 on the computer...
http://www.robertpowersmotorsports.com/OtherCars.html

 

[celticsam]

Both sites saved into favorites. From what I read, keeping the computer will not only work, but be cheaper (with the lock-up torque converter and all...)...and the AIR injection can be deleted with no hassles. All good news! Looks like I'm doing an engine swap come April...

Neil

 

[DoubleV]

Something to consider about running on the computer with your 350, the carbs for the later swirl port head 307's were calibrated very lean. They can be modded though. If you can find an earler pre 85 CCC carb in good shape, this may be a cheap easy alternative. Also the computers on those later 307's had really funky timing curves. It'll still work, but the 350 won't run to it's fullest potential. You can always just swap in an older computer that would work better and won't cost you hardley a thing.

 

[gearhedjon]

If your keeping your quadrajet which sounds like you are, only the primary side is computer controlled. When the secondaries are called into play, the computer is not in control any more. It is just like a ccc 2 barrel. The secondaries can be modified any way you want. You may want to look for an earlier carb due to a to lean condition under load. By the way do you know you do not have to run a single exhaust with the left side pipe going under the pan to the right side?

 

[celticsam]

Do NOT have to or DO have to (run dual exhaust)? I was planning on bringing the pipes together where the Y pipe meets (ala X-pipe) and going dual from there back. The O2 sensor would connect into the front of the X-pipe, giving it the full reading of both cylinder banks. I was also going to run dual cats (because I am somewhat environmentally friendly) back to a pair of flowmaster 40's. I thought the "lean" carbs started in 86. If they started in 85, I'll need an earlier carb and distributor...say from an 81-84...but wouldn't I also need the ECM as well...and would it be compatible with the 85 harness? Crystal clear is becoming clear as mud...

 

[celticsam]

One more thing. Keeping the quadrojet because of the small primaries. Decent fuel economy (comparatively) with normal driving....and 750 cfm at WOT (after opening up the quadrojet's secondary)... My other option was to KO the computer and run a Performer intake and carb, but then the AC wouldn't work (glad to hear the gauges are on a separate harness...). Swapping an engine I can do. Wiring is a nightmare for me!

 

[BuickOldsPontiac]

Do NOT have to or DO have to (run dual exhaust)? I was planning on bringing the pipes together where the Y pipe meets (ala X-pipe) and going dual from there back. The O2 sensor would connect into the front of the X-pipe, giving it the full reading of both cylinder banks. I was also going to run dual cats (because I am somewhat environmentally friendly) back to a pair of flowmaster 40's. I thought the "lean" carbs started in 86. If they started in 85, I'll need an earlier carb and distributor...say from an 81-84...but wouldn't I also need the ECM as well...and would it be compatible with the 85 harness? Crystal clear is becoming clear as mud...

Exhaust shouldn't matter, you can do whatever as long as the ECM has an O2 sensor. If you are going with cats go with some hi flows.

The distributor wouldn't change regardless of the carb. The intakes on the late 307s are restrictive, but I don't think you where using it anyway.

As far as the lean carbs, I am not sure. Since the ECM is controlling the fuel delivered via the primaries, it means during closed loop operation the amount of fuel is a function of the 02 readings therefore it shouldn't be to lean or rich. Or another way to say it, if the ECM doesn't see the right amount of fuel it will add or remove it as necessary.