So... I got this motor, and am trying to figure out how to hook everything up to it so I can run the car again (FINALLY)...

Now, I'm thinking that the thing that's capped off in this picture is the EGR. I'm sure I can hook this up again fairly easily.

Someone please correct me if I'm wrong though

 

I have NO idea what this coily spring thing is though... any ideas anyone?

I feel like such a noob asking this... but hey, better to sound stupid now, and get it right later than to not know WTF I'm doing and end up buying a new motor later heh.

 

The number on the intake is 3919803 ... I cant figure out on gmpartsdirect.com how to find out what intake that is so I can figure out what kinda setup this guy had the engine running.

 

Looks like a hot air choke...the crappy non-electric kind. Leave it blocked off.

 

I think that is one of those old fashoned automatic choke thingies. Operates like a thermostat coil or thermometer. I don't see an EGR port anywhere.

 

So the first picture is a hot air choke that I should leave blocked off (even though I'm using my Q-Jet?)

and the 2nd one is some weird thermometer that I'm still confused on the use of (hah) and is useless to me too?

 

That is the same thing I was looking at. Just called it something else. I think hot air choke is the right term.

 

first pic
is a manifold vacuum port hook the trans modulator hose there

second pic is for choke block this off

 

allrighty. So both stay blocked/inactive... super.

Would my LG4 intake be better? I believe it to be an iron intake.

The intake on it right now is a 3919803 casting number (which I cant find any info on)

 

The item in the first photo is the TVS (temperature/vacuum switch) for the EVAP canister, air injection, or vacuum advance for the distributor.

 

pictures are worth a thousand words!

When I saved that picture it said it was for the Canadian models... so I cant help but wonder if the TVS is only for vacuum operated carbs and dizzy then?

 

A million thankyous for that! That matches my car which I was unable to locate a decent diagram. Where did you get that?

 

Vader, could you post that diagram in this thread/sticky? https://www.thirdgen.org/techbb2/sho...hreadid=277272

Think it would be handy for many folks.

 

I'd say ditch the manifold for something not stock, then there are no strange things on it to connect up!

 

There is nothing "strange" about any of that stuff at all. Looks pretty ordinary to me.

The intake is a pre-71 one. Looks like a 69 or 70 model.

The water outlet is off of a later model vehicle, with some sort of broken-off temp sensor screwd into it. I'd guess the water outlet came off of a mid-70s vehicle, and that the temp sensor used to be the thermal vacuum switch that was used in the EGR system back then.

The intake doesn't have EGR at all. Aside from the necropsy on the temp sensor, it does not enter the picture at all. Delete all other references to EGR from your consideration.

The 2 vacuum ports on the fitting behind the carb are for transmission vacuum (to a Turbo 350 vacuum modulator), and the feed to the cabin for HVAC. Nothing to do with EGR.

That intake lacks the port on the front for the EFE valve, if you're putting it on a L69 or LG4 and intend to keep the emissions stuff operational. It also lacks the accessory bolt on the front next to the water outlet, for the later style alternator bracket (about 78-up). And of course that water outlet lacks the port for the CTS, which is critical if you want to run the ECM controls. You can buy a cast-iron water outlet and fix that easily enough though.

The coily thingy is the choke thermostat. It's for the choke system known as "divorced". It works very well, better than any other type of choke except electric, IMO; problem is, the carb has to be equipped accordingly. Odds are yours will not be so equipped. So I'd suggest taking it off and putting it in your box of goodies to save, and using a carb with electric choke instead.

That type of intake puts exhaust gas RIGHT IMMEDIATELY UNDERNEATH the front of the carb, in that narrow passage. There is a specific gasket setup that you MUST use. If you use ANY OTHER gasket setup, you WILL have an exhaust leak, and or you will DESTROY the carb. The gasket system can be looked up as the one for a 69 Chevelle 350. That application will get you the right thing. It will be a thin paper sort of gasket, and a stainless steel sheet. The gasket goes against the intake and the stainless piece goes on top of that, and the carb goes on top of that. DO NOT attempt to use any other style of gaskets, above all not the late-model thick gasket with the phenolic insert around the carb bolts; or disaster will surely follow.

The correct alt bracket would also be the one for the 69 Chevelle 350.

You can use your LG4 manifold if you want, then none of this matters. This is probably a somewhat better intake than the LG4 one as far as flow, but it's iron instead of aluminum, so it's ALOT heavier as I'm sure you've noticed. Personally I wouldn't use either one, I'd go to ebay or somewhere, and get a ZZ4 one. Oh wait.... I can't do that, because I already did.

 

Thanks so much RB

I ended up putting the LG4's manifold back on. The gasket thing scared me (lol), and I'm cheap since this motor is supposed to get me to where I need until I get the other one built so I'm not gunna get a ZZ4 one for it (yet).

The final step in deciding whether or not I should put the LG4 one back on was the lack of EGR (I want to keep all emissions systems), and the lack of bolt for alternator bracket.

My friend and I sat around for about half an hour trying to figure out how to put the alternator on last night when we finally realized that it was missing a hole. I'll post pics after I get home from work today.


Thanks again for all the priceless info

 

Sounds like the heads are original to the intake if there are no accessory holes!

 

The heads have the accessory bolt holes; you can see the boss in the pics.

The intake is however missing the alt bracket hole. Here's a ZZ4 intake, showing the hole in question.

The earlier model bracket system had the alt bracket on a stud that holds the water outlet on. The pass side bolt is replaced with the stud. That bracket was used from 69 to about 72. In fact, that looks like what the PO had; the stud is still in the water outlet in the pic.

 

Maybe I'm blind, but I see no picture showing the front of the heads

 

It's moot now because the LG4 intake is going on, but that old manifold requires an old q-jet, too. The exhaust passage goes beyond the "later" q-jet foot-print. The bolts match up, but a little piece of exhaust passage will remain uncovered.

Ask how I know...

(I was also wondering if the pictures have been switched. What I see doesn't match the verbage.)

 

The very first pic, if you look at the rear of the driver's side head (top left of the pic), you can clearly see that it has the "boss", such as it is, for the accy bolt holes. That surface of the head would slope in toward the valve cover more if it was early model heads.

five7 is exactly right about the exhaust leak: at one ond of that little "trough" passage, the other styles of gasket won't cover it up, and it will spew exhaust up from there. Although, it's the gasket setup, not the carb, that needs to match up. Plus of course, if you put a carb on that style of manifold without the right stainless steel sheet piece, there will be exhaust right directly on the base of the carb. Not a good thing.

 

The old q-jet throttle plate had a little nub there that the later ones don't have. The gasket isn't enough.

I did find, however, a multi-level gasket/shim sandwich heat insulator that had the nub. The carb base still didn't cover it, but the shims had enough stiffness to do the job.

I think I see what you mean about the head accessory bolts (the "boss"). However, there isn't anything "capped off" in the first pic as the originator indicated.

(I'll have to admit, seeing the divorced choke thermostat mistaken for an EGR valve/passage did give me a chuckle. But, then, I didn't know much about 1930's-era Chevys when I was in high school, either...)

 

But that's the back of the motor...

 

The rear of the driver's side head, the part we can see, is identical (one hopes) to the front of the pass side head.... which is of course where the alt goes. There's bolt holes in both ends of the heads, or not in either end, as the case may be.

 

They are 434 casting heads ('75 305 heads IIRC). The back of the passenger side head has 3 holes for accessories, and the front of it has 1. And vice-versa for the driver's side head.

At first I was worried about there being enough holes for the accessories, so I put the accessories on there (way harder than it sounds when you dont have anything but the parts to figure out how they went lol).

Here's a picture of the motor when I plopped it in before the intake swap and put all the rest of the garbage on there. You can see the bolt holes fairly well. If I had some webspace I would host the rest of the pictures so y'all can take a gander at 'em lol.

BTW, what DOES the EGR look like? I have looked around a little but couldnt find any pictures lol.

 

17,000+ posts can't be wrong. Whata font of knowledge.

 

The picture RB posted shows the EGR boss to the rear of the carb mount, with the "hot air choke" boss in front of it (which is open to the exhaust cross-over passage, and on that particular manifold, would have to be blocked off).

Here's a picture of an EGR valve.

 

Thanks Five7 I always thought it was some sort of vacuum pump or something

 

Vacuum servo...