Big Block only parts.

[69SCSS]

Been looking around for a list that has the differences between the small block and big block parts. I'm going to be running a big block in mine since it's originally a 396 truck, and the frame is a big block frame. So, I know the engine stands are specific. What else is big block only? Here's my list:

- Throttle linkage (will probably change to 71/72 style)
- fan shroud
- shifter linkage

Anything else that's not part of the engine that I missed? I wouldn't think much else, it's all engine / trans from there.

[70STOVEBOLT]

What makes the shift linkage big block only? Because of the engine position?

[kwmech]

Originally Posted by 70STOVEBOLT

What makes the shift linkage big block only? Because of the engine position?

Yup, but you can use the small block linkage if you reposition the frame bracket and redrill

[SS Tim]

Cab floor, heat shields, dual exhaust brackets, manual crossmember, drive shaft and differential depending on specific application.

[70STOVEBOLT]

SS Tim, is the driveshaft only unique because of the length? Also, what is different about the differential, say for a C10?

[SS Tim]

There are a myriad of drive shaft service part applications. The best way to check is to determine exactly what you want to end up with and see if what you have crosses over. Again the parts manual is for service repacements but most carry Big Block and 4-speed application exclusions.

[PanelDeland]

All of the accessory brackets are specific.PS pump,alt,A/C, and expensive to boot.IIRC the clutch z-bar if you run a standard.

[northerngmc]

Originally Posted by 69SCSS

I'm going to be running a big block in mine since it's originally a 396 truck, and the frame is a big block frame.

Do you mean the engine mounts or is the frame different on a big block?

Sounds like my big block might be worth a bit just in parts!

[69SCSS]

Originally Posted by northerngmc

Do you mean the engine mounts or is the frame different on a big block?

Sounds like my big block might be worth a bit just in parts!

Big block frames are clearanced in the engine compartment to clear the larger engine.

[Tx Firefighter]

Show me a difference in the frame itself where it's factory clearanced between big and small block trucks. Or even an inline 6 for that matter.
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[69SCSS]

Look at my build thread, post 41. You can see it, on the inside of the frame, it is cut back behind the front crossmember. There's a thread in the build section of someone cutting their frame to match this.

[popsthebuilder]

I was thinking of swapping out a 307 for a 402. I thought all I would need was different mounts. guess that's not the case huh. 72 c20

[Tx Firefighter]

I have built three big block trucks of my own. None of them were big block originally. On all three of them, I used factory big block mounts to do the install. Absolutely no cutting or trimming is necessary at all. They fit properly and clear everything. I did look at your thread in the referenced post and can't figure out where you're referring to that you modified.

[Tx Firefighter]

I went back 9 years and found an old thread I posted a bunch of pictures in. That was a 1970 model, original 6 cylinder 3 speed column shift truck. I converted it to 454 and turbo 400 with all OEM parts. The only deviation I made from exact OEM was using small block engine rubbers in place of the more expensive big block ones. But, the frame stands were original 68-71 396/402 big block stands. It all bolts right in with no mods at all.

http://67-72chevytrucks.com/vboard/s...d.php?t=110775

[69SCSS]

http://image.truckinweb.com/f/images..._ton_frame.jpg

That's a regular frame, see behind the crossmember the frame is straight on the insides. Then look at my frame and you'll see the difference. The bog block trucks had them cleared for more room. I'm sure a big block will fit without anything hitting on a regular frame, but they did have a seperate frame for big blocks.

You can see the difference pretty well in this pic.

[kwmech]

Never seen a frame difference in all the trucks I have owned both large and small block. Even converted a few back and forth

[popsthebuilder]

Had me worried for a minute there. Thanks for clearing that up Tx firefighter. Not trying to get too far off topic but what type of hp/ tq can I expect out of a fresh 402 4bolt built with somewhat performance in mind and pump gas?

[SS Tim]

IIRC there was a running change on the frame flanges when the Big Block was released in late 67 clearancing the frame for the exhaust manifolds. This change was incorporated in all frames subsequent.

[67c10rustbuket]

Originally Posted by SS Tim

IIRC there was a running change on the frame flanges when the Big Block was released in late 67 clearancing the frame for the exhaust manifolds. This change was incorporated in all frames subsequent.

Exactly

If I remember correctly, the top flange of a '67 frame measures 2.5" wide while a 68 frame top flange is 1.8" wide. I got these measurements from my '67 frame and my friends '72 frame. They ALL got narrowed once the BBC was an option in '68 to allow room for the exhaust on BBC, when equipped.

[cdowns]

lift it up put it down into the frame if nuttin hits it is good to go// too many anal people with clipboards are running around

[Tx Firefighter]

Originally Posted by popsthebuilder

Had me worried for a minute there. Thanks for clearing that up Tx firefighter. Not trying to get too far off topic but what type of hp/ tq can I expect out of a fresh 402 4bolt built with somewhat performance in mind and pump gas?

I wouldn't be the guy to offer an opinion on the power figures. Pretty much all the junk I build gets stock engines with aluminum intakes, cast iron exhaust manifolds and modest carburetors. I'm kind of a one trick pony nowadays. I wasted too much money chasing horsepower in my air cooled VW and 5.0L Ford days. Now I just like reliable and trouble free stock-ish stuff.

[popsthebuilder]

Thanks still.

[70STOVEBOLT]

So, what else is big block only? We know the motor mounts/frame stands, shroud, shift linkage, throttle linkage/cable, cab heat shield, exhaust brackets, drive shaft, high hump floor so far...

[burnin oil]

Originally Posted by popsthebuilder

I was thinking of swapping out a 307 for a 402. I thought all I would need was different mounts. guess that's not the case huh. 72 c20

400sb would be a direct bolt in and gain you almost 100 cubes. Reuse all your parts except the balancer and flywheel. Heck tell everyone it is still a little 307 if ya like.

[70shortfleet]

The u-bolts that hold the lower control arms to the frame are larger on big blocks