Bad Combo?

[350runner]

Just splice the black and green wires together.

Sent from the dust in front of you!

 

[MadOgre]

Not sure about the TBI dizzy either, but diddo on everything else.

 

[RangRayy]

There is also a way to use the TBI dizzy if it's similar to the ESC dizzy. There will be a couple of wires you snip and twist together. Once you do this, then it operates just like a standard 1974 HEI ingition where the ICM doesn't do any timing adjustments. So you'd then set your initial timing and that's what you got other then centrifical or vacuum advance.

And someone may want to confirm for me that can be done with a TBI dizzy too. I know it can ESC, but not 100% positive on TBI. I'm forgetting to much. Getting rusty.

Now switching over to a reg non computer controlled dizzy and carb do I just un plug the ECM so everything else will work with out it? That way when I go to fire it up it doesn't go apeshit on me and freak out?

I want to do what MadOgre suggested and get the carb and intake on with the new dizzy and dial in my timing before I put the cam in. That way the carb is all set up and no issues when I try and fire it up with the new cam.

 

[Joe383]

Say what you want rich but your wrong. Get on line and look up the instructions for your self on the holley web page. I trust them more than you on this subject. This is how I have always hooked up my dizy un less I had it locked out. Why would they put the port for your distributor on the carb and have you use a different port? My current hot rod runs just fine like this.

On the torque converter subject... I am running a pretty large roller for a stock converter and have torque as soon as I touch the gas. It has more torque right off the bat than the old motor did. You can feel if I step on it the first 500 RPM are not as strong as the rest and I should be running a 2,000-2,500 RPM stall if I was drag racing or something but either way I still have more power off idle than the stock motor. I am running 214*/224* with .474/.474 lift and the cams your looking at are a lot smaller than this so I would not worry about not having torque off idle at all. As long as you pick matching parts you will have more power than you did before. Just make sure to match your intake and carb and don't over size either. You can axially over size your carb and not notice much if its a vacuum sec carb but too large intake can kill low end. I had a 725 road demon on a mild 350 with an RV cam and loved it but if it would have been a double pumper the truck would have not drove well.

 

[rich weyand]

You're right in that the Holley instructions say that. Funny they should get that wrong.

The forums administrator on the Holley site clarifies that ported/timed vacuum is only for emissions-controlled engines here, however:
http://forums.holley.com/showthread.php?8494-Constant-vacuum-on-ported-port

 

[MadOgre]

Say what you want rich but your wrong. Get on line and look up the instructions for your self on the holley web page. I trust them more than you on this subject. This is how I have always hooked up my dizy un less I had it locked out. Why would they put the port for your distributor on the carb and have you use a different port? My current hot rod runs just fine like this.

On the torque converter subject... I am running a pretty large roller for a stock converter and have torque as soon as I touch the gas. It has more torque right off the bat than the old motor did. You can feel if I step on it the first 500 RPM are not as strong as the rest and I should be running a 2,000-2,500 RPM stall if I was drag racing or something but either way I still have more power off idle than the stock motor. I am running 214*/224* with .474/.474 lift and the cams your looking at are a lot smaller than this so I would not worry about not having torque off idle at all. As long as you pick matching parts you will have more power than you did before. Just make sure to match your intake and carb and don't over size either. You can axially over size your carb and not notice much if its a vacuum sec carb but too large intake can kill low end. I had a 725 road demon on a mild 350 with an RV cam and loved it but if it would have been a double pumper the truck would have not drove well.

Your truck will run with out the vacuum advance hooked up at all Joe383. The point is though, what is the proper setup for good performance on a non smog engine. As you are aware that when you disconnect smog components that the engine is ultimately plumbed a lot different and for various reasons.

I think Rich summed it up well already when he described how the advance was set up on smog vehicles to work in conjunction with the A.I.R system.

At first glance it would seem as though ported would be correct. Its only when you understand all the secondary processes and facts that the non ported becomes the clear choice. I too used to think that ported was correct. What I have found is that even Edelbrock says ported but that is for legal purposes as they cant be advertising to scrap all your emissions compliant components. A non smog engine is considered a race engine that does not need to be emissions compliant, in the eyes of most corporate companies, other wise you would be running smog compliant engines right? LOL

Anyways there has already been a discussion about the ported vs non ported vacuum advance in many, many threads!

I thought there was a thread but I cant find it so tell you what. You start a thread about ported vs non ported and we will get it made into a sticky for future reference and everyone can have it out in that thread about why or why not. Instead of hijacking this thread.

 

[MadOgre]

Now switching over to a reg non computer controlled dizzy and carb do I just un plug the ECM so everything else will work with out it? That way when I go to fire it up it doesn't go apeshit on me and freak out?

I want to do what MadOgre suggested and get the carb and intake on with the new dizzy and dial in my timing before I put the cam in. That way the carb is all set up and no issues when I try and fire it up with the new cam.

My only concern was that the ECM may run some of the gauges. That sounds unlikely though. So unless you specifically need the ECM for something, which I can not think of any, just disconnect it completely and don't use it. The regular HEI does not need any ECM functions and does not have any provisions for the ECM.

If it were my truck I would simply remove the entire ECM from the vehicle, but you may want to retain it for later use? I dunno?

Did you find out if your block has roller lifters? If so, did you call Comp Cams?

 

[Joe383]

My 670 street avenger was not designed for an emission motor. Double pumpers are the same way. Why would they put emission compliant or compatible parts on a non emission/performance part? Ya I know you don't have to have the vacuum hooked up. My 454 has the advance locked out. The distributor came out of a wind machine. It kills the fuel mileage. When I rebuild the 454 it will still not have vacuum advance as I will be probably be running a 3,500 RPM stall. Hook up your advance at the intake or bottom of your carb, drive for a week and monitor performance and keep track of your fuel mileage. Put it were it goes and do the same. You will figure out were it is suppose to go.

 

[RangRayy]

My only concern was that the ECM may run some of the gauges. That sounds unlikely though. So unless you specifically need the ECM for something, which I can not think of any, just disconnect it completely and don't use it. The regular HEI does not need any ECM functions and does not have any provisions for the ECM.

If it were my truck I would simply remove the entire ECM from the vehicle, but you may want to retain it for later use? I dunno?

Did you find out if your block has roller lifters? If so, did you call Comp Cams?

I cannot think of a reason that's why I was asking haha. I had planned on removing everything from wiring harness down the the box. If it will bring some money I might sell but otherwise I'll keep it in the garage for a just in case moment.

No I haven't checked yet nor have I got the motor pulled. It was way too hot this last weekend to be out there. It looks like we will have some mid 70s this weekend as long as the rain holds off.

 

[RangRayy]

There are a few items that just dawned on me....

1. The new HEI distributor will need power
2. The electric choke on the carb will need power
Both of which probably need to be tied in with the ignition somehow.
3. The in tank fuel pump will need power or a signal to turn on since I believe it's supplied from the ECM and if I've read right that goes through the oil press switch.

Where on earth could I tie in the dizzy and choke? Not together obviously

 

[RangRayy]

Most don't even bother with the cover. But I have a few times I thought "Oh it has a cover it must have the provision" only to find out that it does not and for some reason it had a cover on.

I finally got the motor out and on the stand. Which it is non roller from the factory. But with it on the stand I was curious and I pulled the cover where the fuel pump would be.... And to my surprise there was a gasket and oil on the backside of that plate. Looked up in there and boom the hole is there for a pushrod and a oil journal into the oil pan.

Should I still stay away from a mechanical fuel pump and just run the in tank electric ones?(I have the 2 tank truck but only the left tank works currently)

Also would the 12-300-4 have the lobe for a fuel pump?

 

[MadOgre]

I finally got the motor out and on the stand. Which it is non roller from the factory. But with it on the stand I was curious and I pulled the cover where the fuel pump would be.... And to my surprise there was a gasket and oil on the backside of that plate. Looked up in there and boom the hole is there for a pushrod and a oil journal into the oil pan.

Should I still stay away from a mechanical fuel pump and just run the in tank electric ones?(I have the 2 tank truck but only the left tank works currently)

Also would the 12-300-4 have the lobe for a fuel pump?

Yes the 12-300-4 has a mechanical fuel pump provision. I was pretty sure that the in tank pumps were not operated by the ECM? You know I have never owned an 87' but I would bet money that there is a larger 12 gauge red wire used for something to do with ignition on the 87 TBI. Most likely the lead to the coil. You are just switching it to a different location. Just use that wire for your power to the dizzy. The electric choke should be wired through the oil sending switch. If the in tank pumps work I would just get a regulator and install that instead of trying to suck through the in tank pumps with a mechanical fuel pump.

 

[RangRayy]

Yes the 12-300-4 has a mechanical fuel pump provision. I was pretty sure that the in tank pumps were not operated by the ECM? You know I have never owned an 87' but I would bet money that there is a larger 12 gauge red wire used for something to do with ignition on the 87 TBI. Most likely the lead to the coil. You are just switching it to a different location. Just use that wire for your power to the dizzy. The electric choke should be wired through the oil sending switch. If the in tank pumps work I would just get a regulator and install that instead of trying to suck through the in tank pumps with a mechanical fuel pump.

I had figured the fuel pump would be powered by the ignition somehow or through the oil press switch. I thought that on tbi motors if no oil press it would shut down the fuel in attempts to save the motor from damage.

Which wire would you suggest lol?

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This was before I tore things apart.


Also I have a couple big wires going down the drivers side not sure what they are for.

 

[MadOgre]

Hmmmm Im not sure. Maybe @chengny or @circuitguy could help

 

[85c10owner]

I didnt read all 10 pages but in my research for doing a TBI swap into my 85 with a little extra power I found a page that suggested these heads.

http://www.summitracing.com/parts/sum-162109

Actually there is another part number if you want center bolt valve covers but they do have a CARB number if you need to smog. They would be a grea upgrade over the swirl port heads.