G506 Engine Bay Length?

[TexasG506]

Hi all,

My g506 came with no motor and I have a few options in my garage to swap in. I already pulled the radiator and sheet metal so taking measurements is tough right now. Does anyone know what either the length of the original 235 was? Or what the usable length is between firewall (without modification) and radiator is?

I've seen some SBC swaps and I think that motor is ~30" from bellhousing flange to tip of water pump, so it's obviously fair to assume any 30" long motor should swap in. Is that the limit? I'd think the original straight 6 would be longer than a V8 but when I measure from my firewall to the bolt pattern for the radiator support I'm seeing ~30", which adds to my confusion here.

Any input?

Thanks all

[Tonywan Kanobby]

I’ve seen a small block in a 506 and it was real tidy and worked real well. I read your post last night and I started digging through a couple of manuals that I thought showed some dimensions. Didn’t find any there but found numerous websites that do have numbers that relate to swapping motors. Didn’t see the 235 anywhere, but shouldn’t be too hard to find out.

It’s all frozen outside right now but will warm up soon. I can pop the hood on mine and lay a tape measure down in a bit and come up with a few numbers.

[Tonywan Kanobby]

So I got out there with the tape. I measure 32 3/4 inches from the firewall to the radiator core. 31 inches from the firewall to the radiator upper (tank).
For the 235 motor I’ve got approximately 33 1/4 inches from back of block to front of fan blades (this a 1959 motor with no mods to the water pump). The block is roughly 27+ long.

[Tonywan Kanobby]

So I got out there with the tape. I measure 32 3/4 inches from the firewall to the radiator core. 31 inches from the firewall to the radiator upper (tank).
For the 235 motor I’ve got approximately 33 1/4 inches from back of block to front of fan blades (this a 1959 motor with no mods to the water pump). The block is roughly 27+ long.

These vids may or may not be helpful:

https://youtube.com/shorts/6OK-yFiaCHM? ... FaSvyyBu3F
https://youtube.com/shorts/m884x_wnTEw? ... QsvM6kp--d
https://youtu.be/TWI6Eu90nMQ?si=Q-yO7YF76Ew0zbp1
https://youtube.com/shorts/5JVCypL2SIQ? ... Hk5vlDcclu

[TexasG506]

So I got out there with the tape. I measure 32 3/4 inches from the firewall to the radiator core. 31 inches from the firewall to the radiator upper (tank).
For the 235 motor I’ve got approximately 33 1/4 inches from back of block to front of fan blades (this a 1959 motor with no mods to the water pump). The block is roughly 27+ long.

Huge thanks my man! Much appreciated!

So the motor is 33.25” long but the space from firewall to radiator core is 32.75”? And 31” to the tank but obviously the fan must sit below the tank.

So how does a 33.25” motor fit in a 32.75” gap? What am I missing?

[Tonywan Kanobby]

With the 235, the back of the engine goes into the cutout (or maybe say depression) in the center of the firewall. One of the vids shows that I think.

And yes, the upper tank is way above the fan.

[TexasG506]

With the 235, the back of the engine goes into the cutout (or maybe say depression) in the center of the firewall. One of the vids shows that I think.

And yes, the upper tank is way above the fan.

Gotcha so your “firewall” measurement is from the flat main body of the firewall and not from the depth of the depression. I’m sure it’s clear on the video. I’ll grab my laptop and check them out now.

Thanks for the help.

Just watched the second short, looks like 33.75" or so from firewall "depression" to radiator tank (hard to see exactly), and as you previously measured there's a 1.75" difference between rad tank and rad core. " 32 3/4 inches from the firewall to the radiator core. 31 inches from the firewall to the radiator upper (tank)."

So the longest a motor could be, likely in a straight 6 config which can utilize that firewall depression, is 33.75" + 1.75" for a total of 35.5". Obviously that's basically contact to contact so I'd need to come in a bit on both sides to actually fit. But that answers my question!

[Tonywan Kanobby]

Cool. You’re welcome. It will be neat to see how it all works out for you. Maybe some others will chime in on the sbc swap. I know it’s not particularly “kosher” historically, but it seems that parts availability, cost, and finding shops that can handle the process of rebuilding the “sixes” is getting tougher all the time. I mean, it’s great if you have the wherewithal to get that done.
I’m happy my motor is running strong. Knock on wood, it’ll stay that way.
Let me know if you need any more measurements. Take care.

Tony

[TexasG506]

Cool. You’re welcome. It will be neat to see how it all works out for you. Maybe some others will chime in on the sbc swap. I know it’s not particularly “kosher” historically, but it seems that parts availability, cost, and finding shops that can handle the process of rebuilding the “sixes” is getting tougher all the time. I mean, it’s great if you have the wherewithal to get that done.
I’m happy my motor is running strong. Knock on wood, it’ll stay that way.
Let me know if you need any more measurements. Take care.

Tony

I’m not doing an SBC swap, god no.

My 506 came without a motor so I’ve been looking at alternates. I have a ‘48 ford Flathead 6 and v8 here with 4 speed. That’s my most likely swap unless I find an original 235 laying around with trans for dirt cheap.

[Tonywan Kanobby]

Quote:
“I’m not doing an SBC swap, god no.”


Oh boy, I’m in trouble now!!

[TexasG506]

Quote:
“I’m not doing an SBC swap, god no.”


Oh boy, I’m in trouble now!!

Haha no offense to the SBC squad, just way too boring for me.