Hot Rods AD_NAPCO's 39 GMC Rocket 324 Build

Well, my goal is to have a running, driving, stopping, presentable truck for my wedding date on July 28th next year. The budget is as lean as I can make it without doing anything half-assed...

I have to work budget consciously but not cheap out if it's going to be a detriment in the long run.

Oh, and one other thing, while perusing the local craigslist looking for olds parts I found a guy that has a 55 Super 88 Holiday 4 Door hard top here in town that his wife's parents bought brand new. He's looking to sell but the car hasn't run in about four years. His ad was soliciting to help him market and sell it for a commission, as well as doing the tune up to get it running again... So I went and looked at the car and it's not as nice as he described. I'm going to have him bring it over here and I'll spend some time getting it running. Seeing as this car is still factory and everything is where it's supposed to be I think the normal tune up items should work fine. I don't anticipate near the headaches that I've had with my 56 motor. We'll see.
It'll be nice to have a totally virgin rocket to look at and reference. Mine is missing so much in terms of linkages fittings... At least when I need a part I'll be able to post a pic and say without a doubt I need this or that specifically!

I may also ask you guys opinion on what this car could conceivably be worth, or at least a fair place to start the negotiations. Truth be told if I had the cash and the extra room I'd try to buy it from him. More on that later.

 

Quick update... Still no real progress. I've been sidetracked on a couple other projects. I had a parts truck that is donating sheet metal etc. to this truck that was taking up space in my driveway. The past couple days have been about tearing that truck apart and selling off the carcass. Keeping the cab, which I pulled off of it today, and tomorrow will be about building a dolly for it to roll around on. With that out of the way, I should be free to finally move forward with the rocket motor, if I don't start a new gig on Monday.

Now, I have a question... I'm wondering if you guys think it'd be better to pull the motor and tranny as a unit, or to separate them before pulling the motor? I pulled a 305/TH350 this weekend as a unit. My guess is that the Rocket/H-M is a heavier combo... Whatcha think?

 

In my limited experience playing around with two 324s with hydros, I think you should have no problem pulling the motor and transmission as a unit. It is a heavier setup, I've heard a couple of guys suggest the 700-800 pound range, but I had no problem lifting and moving them around with my cherry picker. Moved one with just one chain from the front on one side to the rear on the other, and the second I pulled with four chains and a leveler...

In my opinion, it's also easier to separate the hydro when it's sitting on the floor. There's 30 bolts that need to be pulled to separate the torus from the flywheel.

Good luck!

 

Take them out as a unit. It's a pain to try and separate them before they're out because of having to remove the torus from the flywheel. Drain the torus (fluid coupling) in addition to the trans before removal. Saves a messy surprise later. As said, they are heavy. I took some stuff off the engine before removal.

 

Thanks for the replies guys... I'll definitely do it that way. It looks like the H-M is shorter by a bit than the TH350, so it should be easier to balance.

Been fighting a nasty cold the past few days so I didn't get up and rolling til late in the day. Barely got the metal cut up and tacked together for the dolly. Still gotta get angle braces and finish weld tomorrow before I can mount the cab on it and move on to the next phase!

 

When you get to the HM rebuild you might contact Gene at:
http://www.restorationhydramatics.com/

.

 

Thanks for the tip on the H-M shop. Salinas is four and a half hours drive for me one way... I'll have to give him a call and see what he has to say.

 

Well, I feel like crap, but I think I'm sweating it out of my system. I managed to get the engine and trans pulled today. It wasn't that bad. It was a lot worse unhooking all the shit to free it up. Even so, I'm feeling whipped after doing that with a bad cold! Next adventure will be separating the trans.

 

Very easy and quick since it is not a stuck motor. I assume you already have the lower half bell off to have drained the torus.... so then it's just a bunch of torus bolts, and a few bell bolts..and that's it.




I somehow managed to do it to 2 57's back in the early 60s when I was 13.

 

Actually, I drained the torus through the inspection hole in the flywheel cover. The plug was just about dead center of the hole so I didn't bother pulling the cover or starter. Good to know it's not a big deal!

 

What the hell.. pick up the phone.. I would have drug Campbell and my hoist out there... What ya doing pulling the motor anyways.. need to reupholster that seat first...

Sorry to here of the break-in.. still have space here if you need it...

 

Thanks Dave, but I picked up a brand spanky new 2 ton commie hoist off craigslist for a little less than half price about a week ago and a stand for $20 bucks so I had that covered... I called ya tonight. What the hell? Why don't YOU pick up the phone?

 

Don't remind me of the hassle I went through separating the stuck Olds I have... *shudder*

 

Well, I got the trans separated, and the engine up on the stand. Got the first head pulled and put a dial caliper on the bores and it appears it's already been bored out to 4" with a pretty good ridge at the top of the bore... I'm not real enthusiastic right now.

 

Find out if it really is a 56 324 first. Look at the stamped letters/number at the block deck near the 1 and 3 exhaust manifold area, right at the edge.


My 56 block had a large "10" on both sides of the block below the heads, and a 10 at the rear extension of the block.

 

Well, Frank, I found an older thread where you posted some of DON_WOW's numbers.
My block is V1039451 which appears to be a 54 block. The heads are #10's though.

I had dad come out and look at the block, and he did the fingernail check and he said he thinks it'll clean up with a ridge reamer so maybe I panicked a little early...

Do you guys have any idea what the rubber plug is to the left of and above the #2 cylinder? Looks like a water passage blocked off and certainly doesn't want to come out, not that I've tried to force it. The close up pic is of the plug I'm referring to.

 

Now that I know I have a 54 block, and 56 heads, it got me thinking about the H-M and what vintage it might be... My suspicion is 53, based the serial number in the attached pic... I'm wondering though if the first three digits are "ZERO FIVE THREE" or "OH FIVE THREE"

If it were "FIVE THREE - OH" that would signify 53 Oldsmobile according to my copy of the United Motors Service Division On-The-Car Adjustment Service Manual for 1946-1955 Hydra-Matics...


Anyone have any insight into this serial number?

Oh... One other thing. I have possibly a chance to pick up an old Borg-Warner R10 overdrive real cheap. Anyone ever thought about running one behind a Hydra-Matic or is that even doable? I know that manually shifted gear splitters can be run with them but I'm not sure about the R10's.

 

Quote: "Well, Frank, I found an older thread where you posted some of DON_WOW's numbers."


Could you post a link to that thread. I'm trying to figure out some block #'s too.

That plug is supposed to be in the deck by #2 cyl to force water to the back of the engine. All the ones I've seen are a little metal plug not rubber.

 

http://www.jalopyjournal.com/forum/showthread.php?t=629882&highlight=don_wow+numbers



Here is one thread. Further down the thread, I mentioned that some "V" codes were used in 56. DON showed just the "A" series in 56. My V came from a base model 88 which was the only 56 model that still used the "old" Hydramatic, instead of the new Jetaway. Maybe that's why it was a V, I don't know. My V code 56 had a sequence number higher than DON's 55 V spread.


My 56 Hydramatic tag starts with a 55.


I don't know about adding a chunk of that OD trans to a Hydramatic... I can't see it working well, as I think those OD's are freewheeling? ...even if you could handle making adapters, shafts, etc.

 

Okay, that's interesting, looking closer, all of DON_WOW's V codes have 6 numeral digits. Mine has 7 digits so maybe mine is a 56 block afterall. I did not see any "10" cast into the sides of my block or the extension. I did see "9" cast on both the extension and the sides toward the rear.

 

F&J, Thanks for the link.

 

Like was said on maybe that thread; don't put too much value in the casted block numbers. Use just the stamped number on the deck.

56 block will have the larger sized cam journals, compared to older motors.


Geez, I've seen a "9" before...but where? maybe my 55 motor, or maybe on a hamb engine pic..

 

From what I understand, both 54 and 55 were "8" heads. Though that doesn't really mean much, as it seems things got changed around.

Trying to remember, but I think my '55 is stamped with an 8.

 

SHIT. Was prepping the heads to take to the machine shop. Pulling studs. All of them came out easy except the two at the passenger side front exhaust port. Both of them snapped off just below the face of the head with almost no pressure applied... Are those typical problem studs on these heads because of the generator hanging out there on that manifold?

More fun.

 

Managed to dig both studs out without fucking up the threads in the head. Sure am glad my dad's around to help with this kind of stuff. He's about to be 76, and he's dug hundreds of broken studs out of heads, blocks, manifolds, castings of all sorts over the years at his shops. I have only done a few dozen maybe, but those were lots of years ago when I was working full time for him... It feels good to have conquered it but damn am I glad that it doesn't happen that often!

 

Well, I just dropped off the short block, heads, and various cast pieces for tanking and magnafluxing. The machinist I took it to is very experienced with older engines. His dad was Ron Williams of the Williams Brothers. Search the HAMB and you'll see pics of their 29 Ford roadster that broke records at Bonneville in the 50's. In any case he doesn't think it'll just clean up. He thinks it's going to need to be bored if it checks out crack free... He said it'd be about a week before he could get back to me with any information...

Fingers crossed!

 

So, I'm sitting here recovering from some elective surgery which will put me out of commission for working on the truck for probably a couple weeks and I'm thinking about it of course.

I picked up a set of the repop hurst style motor mounts for the 324 off ebay and they look pretty damn good especially for the money. Can anyone recommend a well made prefab frame-side mount for the rubber biscuits that would work (with necessary mods of course) in the frame rail of the 39 GMC pickup?

I spoke with the machine shop yesterday and they had just started cleaning my parts so no work yet on the condition of the block and heads.

 

Most guys would grab a small piece of 2x4 or 2x3 rect tubing at the recycler, then angle slice it. You'd end up with a 3 sided wedge shape. Then weld the big end to the frame.

..or if no welder: You could cut a flat plate wider than the base of the wedge, drill mounting holes, and bring the pieces to a weld shop. Then it would bolt into the rails.


EDIT; When you go to put those Hurst brackets on the motor, go to my 40 Ford build thread to see where you need to grind off a tiny sharp corner near the timing cover bolt. It's not a defect in the mount bracket, it's just something quick that needs doing. There is a good pic there.

 

Yeah, I know it wouldn't be hard to fab up some cave man style mounts... I was just thinking that the mounts I already bought looked pretty nice, I may as well see if someone sold any nice USA made frame mounts that looked just as clean.

I am following your 40 build, Frank, which is what convinced me to pull the trigger on the ebay hurst type mounts.

Thanks!

 

Well, I finally got some news back on my motor. Machinist says the crank magged fine and is actually a 303 crank and "it's within half a thousandth of being round, and still standard" so he doesn't see any need to turn it. The block was pretty full of sludge. He's getting ready to send it through the tank for the 4th time. It did mag fine though. He said the bores measure 3.998 with .006 taper, so he's saying we'll probably need to go .020 more, since the taper isn't uniform, which would put this block at .145 over with 4" .020 pistons... Next step is sonic checking. Number 6 cylinder wall is "water stained." Said it shouldn't affect the motor much but it won't clean out.

So that's it... Now I just wait to hear back on the sonic testing. I'll get in touch with GOATROPER02 and relay the results of the sonic test and see what he thinks as far as wall thicknesses go and if this block is gonna be usable. Fingers crossed!