87 engine in 86 Car

[Reim]

Hi everyone-

I am finally back to getting the 86 Monte back on the road. I bought the car for my son 4 years ago and drove it for 6 months and the engine started breaking rockers and turned out to be too many unknown mods to be reliable. Yeah got a little smoked on the engine, but body and interior is great.

We are just trying to get the car back on the road so we bought a good running 87 SS motor with stock heads, intake and an Edlebrock carb. The harness and ECM is out of the car, but I have it.

Thoughts on putting the 87 engine in along with the harness and ECM? We would like the AC, trans lock up and cruise to work. I understand the CC Quadrajet…any other roadblocks here? My son says it is impossible to put the ECM in…I think it can be done? I know everyone is taking this stuff off not on.

Thanks,

 

[PBGBodyFan]

You can simply swap the ECM harness for the 87/88 style but that is really only specific to the distributor/coil setup or mostly, if I recall. You could put in the 87'SS motor and keep your wiring and computer, just use(or re-use) a large cap distributor/coil setup. On my 86"SS I put in a different (newer) engine in but kept my distributor, also went to the 87/88 ECM to use the ZZ4 PROM but you can use the 87/88 ECM with the 86' harness. I did this almost 20 years ago so I could be forgetting some details but it was fairly straight forward and you have many different ways to go about it, depending on what parts you want to use.

 

[Reim]

Hi PBG Body- I appreciate the reply and information. Ok great news. I have the harness/ECM for the 86 engine and it sounds like they are compatible. Most of the parts are available so we can sort those things out. I am sure there will be more to come.

We will get the engine and trans in and get it to run with the Edlebrock. Once we confirm the engine’s performance we will install the accessories. I’ll post up the results.

Years ago I helped my Dad swapping a 78 Cutlass 3.8 V6 engine with a 79 model. There were some changes year over year. I do recall this and prompted this post.

I appreciate the input. Thank you.

Reim

 

[Clone TIE Pilot]

If the 87 engine has a complete, uncut wiring harness, it will be quite easy to reinstall the CCC system. You jist run the harness through the firewall in the lower passenger side corner under the HVAC box, one connector to the body wire harness, the other two to the ECM. Installing an 87 ECM is a bonus as it will allow you to use a hot ZZ4 PROM chip. Another good upgrade for the CCC system is converting to a 3 wire heated O2 sensor.

When you reinstall the CCC system you will need to retune the engine again. Edelbrock carbs are squarebore carbs that use a different intake manifold than spreadbore Qjets, so you will need either an intake swap or a carb adoptor plate which cause airflow issues. It would probably be better to the engine up for CCC now rather than setup and tune the same engine twice.

87/88 Chevy CCC systems have a few differences from the pre 87 Chevy systems. As PBG already stated, 87/88's used a small cap, remote coil HEI distributor and a different type of ECM. The 87/88's also control the EVAP purge through a computer controlled solenoid. The pre 87's just used a vacuum controlled purge valve with a TVS.

 

[Reim]

If the 87 engine has a complete, uncut wiring harness, it will be quite easy to reinstall the CCC system. You jist run the harness through the firewall in the lower passenger side corner under the HVAC box, one connector to the body wire harness, the other two to the ECM. Installing an 87 ECM is a bonus as it will allow you to use a hot ZZ4 PROM chip. Another good upgrade for the CCC system is converting to a 3 wire heated O2 sensor.

When you reinstall the CCC system you will need to retune the engine again. Edelbrock carbs are squarebore carbs that use a different intake manifold than spreadbore Qjets, so you will need either an intake swap or a carb adoptor plate which cause airflow issues. It would probably be better to the engine up for CCC now rather than setup and tune the same engine twice.

87/88 Chevy CCC systems have a few differences from the pre 87 Chevy systems. As PBG already stated, 87/88's used a small cap, remote coil HEI distributor and a different type of ECM. The 87/88's also control the EVAP purge through a computer controlled solenoid. The pre 87's just used a vacuum controlled purge valve with a TVS.

 

[Reim]

Hi Clone- Unfortunately, I have an 86 harness and ECM. I can look for a used 87 harness and ECM. The Edlebrock is already installed on the 87 engine with the square bore adapter. I do have a non ccc Quadrajet as well. It is good to know about the ECM change and the Chip. The 87 engine did not come with a distributor…I was kind of upset about that. We can buy the small cap distributor.

Once we put the engine in, can we can use the big cap and get the car running? That will be a huge improvement. Once we get it running. I can get a correct ccc Quadrajet and do those 87 changes. Then get the AC and cruise etc. going to make the car useable. Probably get the trans lock up kit to get by.

I am looking forward to getting the car back on the road so he can enjoy it. The body is great rust free and we already put new ball joints, shocks and did all the brakes. Besides the engine everything else has been sorted out. The tach reads incorrectly and the new trans should have the speedometer gear. We should be good to smoke the tires.

Great insight and I really appreciate it.

Reim

 

[Clone TIE Pilot]

You can use an 87 ECM with the 86 harness and carb Just use the pre 87 EVAP setup.. With all years of the CCC system use HEI distributor with computer controlled advance, no vacuum advance. Pre CCC engines use a vacuum advance HEI distributor.So to run the Edelbrock you need to run a vacuum advance distributor, time it, and curve the advance. Then when you reinstall CCC you will need to swap in a computer controlled distributor and retime it. Those carb adaptor plates mess up airflow and interfer with carb tuning.

 

[Reim]

You can use an 87 ECM with the 86 harness and carb Just use the pre 87 EVAP setup.. With all years of the CCC system use HEI distributor with computer controlled advance, no vacuum advance. Pre CCC engines use a vacuum advance HEI distributor.So to run the Edelbrock you need to run a vacuum advance distributor, time it, and curve the advance. Then when you reinstall CCC you will need to swap in a computer controlled distributor and retime it. Those carb adaptor plates mess up airflow and interfer with carb tuning.

Ok great. I have a 87 IROC so it should be the same distributor. The 87 ECM’s are available and some have the chip. Good deal. We’ll see how the Edlebrock runs. It sounded good in the donor car. I have a rebuilt non ccc quadrajet I can put on there as well.

We are cleaning up the new engine a little since it has grime on it. We will drop that one in there. Cannot wait to see how it runs. We put a new true dual exhaust on the car with x pipe so it should sound decent and have a little more power. If it runs and drives that will be a huge improvement.

I’ll post up when we get that done. Hopefully in the next 30 days or so.

Thanks,