Hot Rods AD_NAPCO's 39 GMC Rocket 324 Build

He has not started on the block and is going to take a closer look at the pits and see if he thinks they will clean sufficiently for a 4" bore...

 

I like this thread,and of course your truck.
I really like that you are tenacious about this.
A 350/350 swap would be done by now.
But that isn't the right thing to do for this truck.
The right thing isn't always easy,and the easy thing isn't always right.
Keep at it.

I am sending you a PM requesting some info please.

 

Yeah, never was into the whole 350/350 thing.... It's boring.

Yesterday I got the cab off the frame and out of the way. Today I got the frame pretty much stripped of all extra parts. A few random clips still need to come off but I was beat and out of acetylene and didn't feel like twisting wrenches anymore.

the cross the bellhousing crossmember is unbolted in these pics and I'm missing a crossmember that goes between the running board brackets just aft of the battery box. I'm not sure why they'd have cut that out completely... Seems like it would have made sense to tunnel through it and keep the support in the frame...

Here's a buddy's frame:



and here's mine as of today. Like I said, I removed the crossmember that the bellhousing was bolted to.



You can see here the plate that was welded to the side of the frame to mount the new crossmember to.



Here's the added center motor mount perch that I'm planning on ditching for hurst style mounts off the sides of the block out to the frame rails.



and the nasty cuts that the PO did to clear the 324 head pipes... Gotta make that better.




So, lots to do while I'm waiting on the motor.

 

If you can locate a new rubber front mount, I would stay with the center mount.

 

Why's that Frank? I figured the side mounts would be a more stable, sturdier setup.

 

A truck chassis is designed to twist, so a 3 point is better. Then you are not racking the mounts when it flexes. If it was a car frame with a sturdy center X and boxed, 4 is not a problem.

That mount looks pretty well built, maybe fill the 2 big holes near it if you don't need those holes. But see if you can get a new rubber mount first, I never asked around for one. I would have used the center mount if I could have because simple works best.

 

I gotcha, Frank. Well, I may be adding some additional members to the frame to stiffen it up once I get to that point, but I suppose in the interest of keeping this thing simple, I don't need to reinvent the wheel. It looks like Kanter has the motor mounts, although they have a terrible website and I'm not sure they are the right ones.

I'll look and see if there are any other sources.

 

Well, it looks like I got anothe thin block. Machinist sonic checked it and if he were to cut it .125 over, it'd only leave me with .140 walls at the major thrust surfaces. Ross at Ross racing told me .170 was minimum for a driver. I have three bores that need sleeves. So, the decision is made. I'm gonna go ahead and sleeve it and go .060 over on the block. Not sure if I'll ever be able to rebuild it again, but maybe in the years between now and then I'll find a better block, or maybe a 371 or 394...

 

You must be young.. .. I don't need to worry about such things, like, do I need 20 year or 30 year house roof shingles.

 

I can hear it now,
"if I knew I was going to live this long I would have bought longer lasting shingles for the roof"

 

How thick on the minor side?

Sometimes I move the bores around a little
You say you'd have .140 on the major
But if the minor was say .195-200 you could move it over .025 and squeak by
You don't need valve reliefs in this motor so it won't matter
And the gasket bore is big

Remember what I said about sleeving
Pick the lesser of the 2 evils

Tony

 

Ah, hah...I knew that was done before. I sold my 60k mile 56 block to a restorer. It lost a rod at one point and had a divot in the rear side of the #1 bore which I measured to be .013 at least. The buyer was hoping to use a new set of 30 overs he already had, and I told him a rough measurement of 13 is cutting it too close, unless the machinist is clever. The buyer later did say it went fine with the 30s, so I am convinced they moved the bore back towards #3.

 

I'll ask him what he thinks about doing that tomorrow. See if he thinks it's something he could do.

What's the furthest it'd be advisable to to move a bore?

 

Any update on the motor?
I'll be tearing into a 324 here shortly.
This was a great read. Thanks everybody for the advise given.

 

Well, no update on the motor, but that's mostly my fault. I need to get over to the machine shop. Unfortunately though, I just got a call from the transmission guy, and he says my Hydra-Matic is trashed. So, I'm on the hunt for a new H-M core... Whoever had this truck sure had a lot of fun!

 

The truck is begging for a stick tranny

 

Ya know, Tony, I'm leaning that way. The main reason for keeping it a slip n slide was because it was there, and because my soon-to-be wife doesn't know how to shift a manual trans... She might just have to learn.

 

Hope it all comes together soon for you.
I am missing this build progress.

 

Ad Napco if you are considering a stick, Dale Shore has just pulled apart a stick set up on a Cad engine that appears to be in great shape. He has a short shaft tranny, 50 Olds bell and a flywheel from the Cad available in Temecula, CA. I purchased the Hurst shifter and clutch set from him but they can be found easily. I do not believe that this set up was ever run. My clutch still has the stickers on it from the manufacturer. I do not know if the Cad flywheel will interchange but Paul or Frank most likely would know as well as others who have followed this thread. Good luck with the tranny choice.

 

I left a message for Dale to call me back on that manual trans. I'm going to start a different thread and see if I can scare up some information and possibly sources for other parts...

 

Well it's official... It begged for it and that's what it's getting. I have to wait for it to get boxed up and shipped to me, but I got a 37 Buick top shift 3 speed with 51 olds internals all set up to work with my 56 olds, complete turn key package. Came from a running driving car so supposedly its a bolt up and go situation.

 

Sweet!
Can't wait for some pics.

 

So, the 37 Buick trans mentioned above is crated and on its way. Hopefully it'll show soon. Got my complete rebuild kit ordered from Ross last week. Hopefully all that stuff shows up in good shape! I've been doing metal work on my cab the past few days. Today I'm replacing metal in the floor pan under the gas tank. Amazing how many sins media blasting reveals.

 

Good, you're back!
I enjoyed this thread.

 

Any updates or pics on that Buick set up???????????????

 

Hey guys! Sorry for another long silence. My fiance and I left for an Idaho vacation the day that the Buick trans stuff was due to arrive from the UPS man, and I had just enough time to drag the crates into the garage before we rushed out to catch our flight.

We were gone about eight days into our two weeks up there and got a call that her grandmother had a massive stroke. Had to catch the next available flight back down here to SoCal, and spent a little over a week with her family during grandma's passing and funeral. Had a few days to recuperate and catch up on things before the bachelor party weekend whitewater rafting in Nor Cal, and after two days recovering from that adventure, I finally got to drag the crates out of the garage and unpack them!

I think everything is here. Only things I see that are issues are one broken ear on the top cover of the trans, and I don't have any clue how the pedal linkage setup is supposed to work. I'll probably try to adapt the stock GMC pedal assembly to work with this setup. Anyone know what the proper bolt size on this setup is to hold the clutch and pressure plate on to the flywheel? I may have a tap that I can use to figure it out.

 

a few more

 

Looks great. Nice package with what appears to be everything you will need to plug and play! That crossmember is from an Olds but you probably already new that. The close up shot of the internals seems to show a snapring that is in the wrong place. Never had a 51+ tranny apart but I have had a 50 apart and I don't remember that snap ring being there. Perhaps F&J will jump in here as he has the identical set up and can speak from his experience with the gears etc.

 

Yeah, I'm hoping it all cleans up good and will work fine. I need to find a manual for the 37 Buick so I can figure out what the shift pattern is supposed to be. I think that crossmember is identical to the one I already had in the truck. I don't have a tap that will fit the bolt holes that attache the clutch/pressure plate. I might just take it too the machinist and see if has one. I need to get those two parts and the damper to him so he can balance the motor properly. Anyone know if there is anything special about the bolts that hold the flywheel to the crank? Will the Hydra-Matic bolts work? If not I need to come up with a set.

 

Should have a std "H" shift pattern like any floor shift. Tony would know what size those bolts are.