Finally Starting My Engine Swap

[BrentBTK]

Here we go. After a few months of planning and waiting, I started the motor swap on my '71 GMC yesterday. I ordered a Blueprint Crate Engines 350 with a complete accessory setup installed from Summit Racing. Advertised as 365/401 HP/TQ, it dyno'd at 385/409. I also ordered a new flexplate, torque converter, motor mounts, mini starter, and a "direct fit" aluminum radiator with electric fans. We shall see about the direct fit part, lol. Yesterday, I got the old motor out. All in all, it went pretty smooth. All the required bolts were easy to access and remove. It was a tight squeeze getting the motor out with everything still installed on the front, but she eventually slid out. Today will be spent cleaning up the engine bay and getting everything prepped. Tomorrow I hope to get the new motor ready to go in, and I hope to install it Sunday. I did have one mishap when trying to move the hoist and old motor over uneven ground in the driveway. I had the motor too high and was trying to swing it around and down she went. Thankfully nothing was damaged except my ego. This is the kind of stuff that happens when you insist on doing everything by yourself. Lesson learned. I have a friend coming Sunday to provide a strong back and weak mind, hehe. I DO NOT want that to happen with the brand new motor swinging around! Pics below. I'll be posting here along the way, and I'm sure things are going to come up that get me stumped, so stay tuned...

[yuccales]

Originally Posted by BrentBTK

This is the kind of stuff that happens when you insist on doing everything by yourself. Lesson learned.

Been there, done that. Glad you're ok. I HATE having to ask for help, but sometimes it's the right thing to do! That engine should make your truck scoot right along. Will be watching your progress.

[72c20customcamper]

Ive found its much easier to remove the front clip when doing motor work . Specially working in less than ideal conditions

[BrentBTK]

Originally Posted by 72c20customcamper

Ive found its much easier to remove the front clip when doing motor work . Specially working in less than ideal conditions

I'm looking at that now. I need to replace the core support mounts while I'm at it and that is not going well. The truck has a roll pan on the front, and it is welded to a bar that is welded to the frame. I've remove the core support bolts that go into the frame, and I can pick the whole front of the truck up by the core support. I'm stuck. I managed to get one mount out but the drivers side is squeezed in tight. Complication number 1 found.

[Accelo]

The dreaded "Project creep" is settling in.

[BrentBTK]

Originally Posted by Accelo

The dreaded "Project creep" is settling in.

Ha. Yeah. I'm on a timeline though. This is dumb. I'm guessing in order to remove the front clip, I'm going to have to cut these welds. There is a bar welded along the underside of the rollpan and to both frame ends. I don't know if I want to dive into that and still hope to have the truck back on the road by Monday. There is absolutely no way to replace the driver side core support bushing unless I do though. Decision time...

[HO455]

Sometimes you just have to draw a line and say this will have to be fixed another day.
Get the new mill installed and the truck back on the road. Then you can make a plan for the core support. Maybe fabricate a new bar that bolts in? (A piece of 1" square tubing with tabs on the end. Then drill and tap it so the roll pan bolts to it?) Then you could cut the old one out and not be concerned with saving it.

Another thing to consider instead of moving the engine hoist around try moving the truck instead. Less chance of tipping the truck over.

[BrentBTK]

That's exactly what I've done. I said screw it. The motor is the task at hand, I can't afford any rabbit holes right now. The new one is just gonna go in over the support. We have rain moving in this afternoon, so I don't wanna open up the new motor and prep it as it's not under a shelter. I spent some time prepping and painting the engine bay, and I'm sort of at a stop until the rain comes through and my help arrives on Sunday for the heavy lifting. I went ahead and ordered a new front seal for the trans, a couple exhaust flange gaskets, and some braided trans cooler lines as the ones in the truck were half a$$ rigged to a tiny aux cooler instead of into the radiator like they should be. So many things were done that have me scratching my head, lol.

[BrentBTK]

As I'm sort of at a stopping point until help arrives, I started tearing apart the old motor just to see if I can see the source of the knock and why it used so much oil. So far, I've just taken the intake and heads off. All the rods looked good, no obvious bends or scars, no loose rockers. Once I get the oil out of it, I'll pull the cam out and the pan off and see what everything else looks like. There is a fair amount of ridging at the top of the cylinders, but they don't look bad. Here's a couple pics of the heads and cylinders. Maybe someone who knows more than me can say if those valves look normal or not.

[Low Elco]

Doesn't seem too terrible. Pro tip: If ground is sketchy, pump tires up 50 psi and roll truck under motor. Cherry picker stays more or less still.

[Steeveedee]

Show pics of the ends of the heads and the casting numbers. Those heads have some big valves in them!

[BrentBTK]

Originally Posted by Steeveedee

Show pics of the ends of the heads and the casting numbers. Those heads have some big valves in them!

3973487 is the casting number. The valve covers say RHS (Racinh Head Services) out of TN. That's all I know about em though.

[BrentBTK]

Originally Posted by Steeveedee

Show pics of the ends of the heads and the casting numbers. Those heads have some big valves in them!

3973487 is the casting number. The valve covers say RHS (Racinh Head Services) out of TN. That's all I know about em though.

[tutone]

Im thinking those are early 70s 350 heads. They may have had some port work as well. Pretty decent open chamber heads. Your new engine looks good. Hope the swap goes well.

[BrentBTK]

As I'm planning putting the motor in tomorrow, I'm wondering what the best method is for the motor mounts. I am thinking to bolt them to the motor first, but is that really the easiest way? I can see trying to get the bolts in and lined up under the mount being a PITA.

[Accelo]

Yes, bolt the mounts to the motor first. Getting the center bolt is a pita but it's only way. If you have the stock power steering bracket some of them have to be installed with the motor mount and with the the motor up or out. Be sure it's on there first.

[BrentBTK]

Originally Posted by Accelo

Yes, bolt the mounts to the motor first. Getting the center bolt is a pita but it's only way. If you have the stock power steering bracket some of them have to be installed with the motor mount and with the the motor up or out. Be sure it's on there first.

Thanks Accelo. I noticed that on the old motor. The new one has all the accessories already bolted up, so that's handled.

[pjmoreland]

Loosening the bolts that attach the engine stands to the frame will allow them to float into alignment with the motor mounts when it is time to install the big bolt that threads into the center of the motor mount.

[BrentBTK]

Okay. The motor is in. The install itself was fine, but I have some issues. I had to pull the distributor. Thankfully they include a chisel mark on it and the block. My question is, can I just put it back in with the marks lined up, or do I need to spin the motor to TDC? I don't know if that a dumb question, I'm just trying yo be super careful here. The other issue is the space between the new torque converter and flexplate. It's a solid 1/2". I can slide my finger between them. I'm not sure what to do about that. I'm focusing on being grateful the heavy lifting got done today. Not much else did.

[Accelo]

The gap between the TC and the flex plate is way to large. 1/8" is about correct.
The hub on the converter has two notches in it. They engage with the pump inner gear. With that much gap it may or may not run the front pump. If it does it will not be for long.
You could use spacers on the bolts between the converter and the flex plate. This would be a bastard and I don't recommend it.
Maybe you have an incorrect offset on the flex plate?

[BrentBTK]

The flexplate and torque converter are both new. I had to get a new flexplate when I got the new motor. What am I missing? At this point, I guess I'll try to drop the trans as I'm back to working solo again. Eff. Eff. Eff.

[HO455]

Originally Posted by BrentBTK

Okay. The motor is in. The install itself was fine, but I have some issues. I had to pull the distributor. Thankfully they include a chisel mark on it and the block. My question is, can I just put it back in with the marks lined up, or do I need to spin the motor to TDC? I don't know if that a dumb question, I'm just trying yo be super careful here.

Definitely not a dumb question!

If you did not mark the location of the distributor rotor before pulling the the distributor you will have to start from scratch. The crank shaft will have to be at TDC on the firing stroke. There are numerous videos on the interweb on how to locate the correct TDC. The crankshaft turns twice for every one rotation of the cam .

Then you will have to line the rotor up with #1 spark plug on the cap. The rotor will spin as it engages the cam gear so you will have to start with the rotor off set of where you want it to be.

The 2nd part of installing the distributor is the oil pump drive shaft will have to engage into the bottom of the distributor drive gear. You can see the drive shaft if you look into the block. If the drive slot and the gear pin do not line up you can turn the drive shaft with a large screw driver.

There are numerous videos on the interweb about how to do this. I suggest you watch a few to familiarize yourself with the process.

Good luck and keep us posted.

[BrentBTK]

Thanks HO. This is what I did. I noted the location of the vacuum advance when I pulled it, and when I put it back in, I lined up the chisel marks and the vacuum advace. It slid right in. Sound okay?

[Accelo]

https://www.streetmusclemag.com/tech...rchange-guide/

Maybe this will help sort it out.

[BrentBTK]

Originally Posted by Accelo

https://www.streetmusclemag.com/tech...rchange-guide/

Maybe this will help sort it out.

Thanks Accelo, very interesting article. It seems to be talking about an LS engine though. Im gonna call blueprint in the morning. I ordered a flexplate for a new style SBC. It's flat. Maybe I got the wrong one.