Hot Rods AD_NAPCO's 39 GMC Rocket 324 Build

Here's a view from the other side. You can see where the afj. bracket attaches down on the timing cover. Hope it helps.

 

1950 303 with a 1955 324 top end on it. The 4 bbl did/does have an insulator under it.
The drilled holes in the 324 intake were for a power steering pump and somewhere on th HAMB I have seen a pic of a power steering pump bracket used for an alternator. The bolt holes in the intake are not parallel with the crankshaft pulley. The power steering bracket is shaped to allow for this. I used the base from a 1950 generator bracket, a part that I got with the alternator and the standard aftermarket Chevy top bracket cut down and redrilled. I had to space up the base bracket to clear one of the intake to head bolts. Pics attached.

 

I went out to look at some of my spare motors, two have the generator mount on top, the rest have them on the side, at least one of the 303 4bbl intakes has no bolts for generator or power steering, at least one that has the generator on the side does look like it uses the same stamped bracket that the two on top versions use, the others use a cast bracket, either bolted to the exhaust manifold 303/324 or the head 371/394. the late 394 has a neat alternator bracket that bolts to the front of the head but because of the block being longer than the early motors it won't work on them.

 

F&J, thanks so much! I'll let you know when it gets here.

550Coupe, that's a great couple of pics, just exactly what I needed and I think that's the way I'm gonna try and go. As it stands now, when I put the generator back on top where it was when I got the truck ,the pulley does not line up. It seems to line up when it's on the side however. The hole on teh water pump is drilled and tapped for an adustment bracket there, it was just full of crud. The local auto parts store has an alternator bracket in stock like the one you show, 550, so I'm gonna go snag that and see about fabbing up a base bracket from a piece of plate steel I have here.

Bobert, that looks like a pretty slick setup, but as of now I'm going with a generator. I just like the look of the old tech... BTW, what is that air cleaner from? That is wild! I need an aircleaner for mine and the stock style is just too massive...

In other news, in the process of fiddling with the generator I decided to pull the top radiator hose off the thermostat housing and holy shit it's full of what looks like ashes!
Never seen anything like this before... Vacuumed what I could out, and went to take the bolts loose and of course, they both snap off at the head... Luckily not any lower. Left me just enough to work with. Thermostat housing was aluminum and the neck is eaten to nothing... Gonna need a new one.

Also couple questions about the carb I just picked up. It's a #7007221 and It's missing a vacuum port on the choke coil housing that I notice is present on Bobert's rig, as well as a few other's. I have the vacuum line coming from the manifold and it was hooked up on the AFB that was there before.

Shop manual is on the way. Hopefully it doesn't take too long...

 

They must have change to an aluminum thermostat housing in '56. The '55 is cast iron.

The air cleaner is a "no name" (somewhere I heard that it was a "Century" produced in New York) that I have on permanent loan from my brother-in-law. I remember him using it on an early 50's Caddy in 1958. I've not seen another like it that fits the early 4bbl. The elements are just wound up window screen for which I need to really get some black prefilter material to put around.

I changed to the alternator when going from 6 to 12 volts but understand why you want the generator. they do look better. I didn't have enough room on the right side of the engine to hang anything off the '55 exhaust manifold generator mount without modifying the inner fenderwell. the car is a '50 Olds. Left the mount casting on the exhaust manifold for "future generations".

There isn't a vacuum line on the choke housing. What you see on the choke housing goes to the exhaust hot spot under the carb. The carb is a 1955 and didn't have the linkage dash pot as on the 1956. The vacuum line low on the carb goes to the distributor.

 

I don't think my thermostat housing was stock. It didn't mate up properly to the intake anyway. I'm going to need a proper cast iron part to replace this POS.

I'm in the middle of making a bracket right now and I'm feeling the pain of my tiny compressor and going back and forth beween a hack saw and a cutoff tool to get the plate steel cut. pain in the ass! I need a proper shop size compressor.

I'm still confused on the carb to intake vacuum line (I'm assuming it's a vacuum line) issue... So I attached an image to clarify.

 

I feel you pain making that bracket. I made mine out of stainless. Ask me how many drill bits I tore up? LOL Then I had to polish it! The aluminum t-stat housing came on the later 371" engines. I've got a couple that are crapped up like yours. Good luck.

 

That line is getting it's vacuum from inside the round choke cover. It draws hot air up to the choke bi-metallic spring inside the black cover, then the spring heats up and opens the choke.

 

F&J... That's exactly what I thought, which is why I'm confused as to why my carb doesn't seem to have that vacuum port... If you go back to an earlier post you'll see where I'm asking if I need that port or not. I got the carb number to look for form "CarbKing" John of the Carburetor Shop in Missouri, and he said either 7007000, or 7007221 would do the trick. I got a 7007221 and I'm wondering now if it was built correctly.

Oh, and I finally said screw the cut off wheel and broke out the cutting torch. Now I just gotta eat up compressor time to make the edges clean enough to use. Not gonna worry about pretty right now. I just need it to work.

 

I just looked at pic #6 in post 34. I can't see much of the choke. I think I recall from decades ago, some GM carbs had the pre-heat pipe going to the center of the black cover. Do you have a threaded nipple on the center of the cover?

...or put up pics of the choke side.. The choke needs to get heat from someplace, either hot air, or electrical terminal if it was converted to electric type.

 

F&J... Looks like I get to have a chat with the carb rebuilder... Unless I'm totally missing something, there's no heat to the choke spring.

Also... First stage of caveman generator base plate done! Gotta locate the generator bracket on it so that the pulleys line up and cinch it all down.

Ugly as shit but it'll work, right?

 

you have the wrong cover on your choke housing,
that housing is meant to have a nipple at the center of the cover where the screw driver slot is

 

Yeah... I just sent the carb rebuilder an email asking for a replacement part. We'll see how that goes.

 

Jon probably has books to look up that exact number and tell you if the choke housing is wrong or if the cover is wrong.

I don't trust my long ago memory ...did any GM makes have a 4 barrel with a cover with the heat pipe going into the center? I think I see it in my memory..

 

The carb I have is the '55 7007000.

 

Well, the rebuilder already responded and said he'd send me the right cover, but I'm skeptical because I've seen several pictures of carbs with the housing with the port at the bottom of housing and none with a pipe to the center of the cover... I'll see if Jon will set us straight before I accept the cover... Should I assume the functionality would be the same? Heat to a bi-metal spring is all we are looking for, right?

EDIT: Google is your friend... Just checked google images and I looked for 7007221 and all the pictures of the core carbs show the threaded nipple at the center of the cover. So, that must be one difference between the 7000, and 7221.

 

my '56 shop manual shows the heat riser connection at the center of the housing cover.

also as per the three bolts on the top of the manifold for bracket mounting,
apparently these were not for mounting a generator or power steering

they were for mounting a supercharger

 

^ more parts I have never seen; the blower and those valve covers.

The older guy I just went to see, still had some Olds goodies from when he was a kid, and put them on his 303 37 chev coupe. He has Edelbrock finned covers, and right under the curved Edelbrock name, are the same sized numbers "57". I thought the numbers were glued on, but it looks like they were casted that way. Very strange. He said he bought a J2 powered 40 chevy back then, and those covers were on it. Like 50 years ago.

 

Holy crap... That setup is awesome!

Cool, well, I'm glad we got the choke cover thing sorted, thanks for that.

I'm going to hunt around more for numbers and see if this engine is a frankenstein of different year parts or something.

Anyone got an extra stock cast iron thermostat housing laying around? If so, PM me with details of what you want for it... Otherwise I'll put up a want ad.

 

Spent a couple days with the fiance and didn't get much accomplished with the 39, but this morning I did get the caveman generator bracket mocked up. At first glance, not bad, but at second... The generator pulley lines up only front to back. If you look from the side, it's at a totally different pitch than the rest of the pulleys. I'd expect there to be a special cast bracket or something for the top mount generators to tilt them to the correct angle end for end... I would have to put a lot of shim/wedge on this bracket to get the generator in line.

Any ideas?

 

Take a look back at my original post. Show the front of the alternator wedged up to tak care of that. As explained the power steering bracket that was intended to go there took care of the problem with the bracket shape.

 

Still have my measurements from when I made my bracket. The front hole from the bottom of the bracket ( where it rests on the plate ) to center of hole is 1 5/8". The back hole from the bottom of the bracket to center of hole is 1". See how that works out.

 

Still have my measurements from when I made my bracket. The front hole from the bottom of the bracket ( where it rests on the plate ) to center of hole is 1 5/8". The back hole from the bottom of the bracket to center of hole is 1". See how that works out.

 

I think 49 to 51s had the generator mounted to the intake so there are brackets out there so you dont have to make them.

 

I sawed down one mounting boss on my aluminum intake to get it level. I'd rather have it lower, than higher, so that's why I cut it.

 

That sounds like a good idea... I ended up just shimming up with a stack of grade 8 washers for now. Seems plenty stable. Short term solution until I can get a proper wedge made, or adjust the intake mounting bosses and go the other way...

Also, F&J, thank you so much for sending me a rocker stand to replace my broken one. It arrived today and I got it installed. I really appreciate it!

Now I'm waiting on a new choke cover, a shop manual so I can figure out where my plug wires go, and so I can replace all the ignition tune up parts,
and a thermostat housing.

I think once I get all that sorted I'm ready to see if I can get her to fire!

 

Correct. That bracket is what I used and redrilled for my base.

 

So, I'm gonna change gears here, and get your guys input on a rear end.

I've decided I'm going to get a complete rear end... Drum to drum. I found a couple rear ends within about 3.5 hours drive.

A 54 Olds rear end, with an estimated 3.07 ratio, and a 59 Olds rear end with an estimated 3.42 ratio. I've been told I can have either one for $350.

This truck is going to be a driver, not racer, so my first instinct is to go with the higher ratio, that said, I'm also intrigued by a higher spline count, stronger rear end, and the possibility of finding a posi to fit the later rear end.

I'm tempted to offer the guy $600 for both and see if he'll bite so I can make my mind up later.

Anyone know how involved moving spring perches is on these axles? The perches are looking to be about 42" center to center on my truck right now. Anyone have a stock 54ish or 59ish rear end they can pull a measurement on the spring perches for? I was waiting on a measurement from the seller but never heard back.

Opinions on the rear end? Which way you'd go? I'm thinking in terms of having no OD and driving down the freeway... Same time, maybe the best way to go is to snag the 59 rear end, drive it with the 3.42 and keep an eye out for something taller to swap out at some point?

 

350 sounds a little steep to me but how times have changed,the 53 Olds I had years ago with the 59 motor and trans had 3.24 gears and had out of the hole performance with plenty of top end too. Back in 84 I payed 150 for a decent 53 2 door body and 50 dollars for a almost running 59 parts car and had it drivable for less then 500.

 

You said a mouth full there...

$350 is by far the best price I've gotten so far and this in California, within driving distance... I've been getting prices from $450 to $550 plus the freight, or yeah, you can have it for $350 but we won't be at that yard for another two months, and we don't know what the ratio is but you'll need to send us a payment for us to go pull it for you because we don't allow the public in the yard and then it'll take about two weeks for us to get it back to you.... Lotta bullshit...

Times have changed for sure... oh, and it turns out the Olds are a popular rear end, and the whole supply/demand thing has driven prices up since '84!