need some newbee help Small Block to Big Block swap

[Chrislidgett]

Hey guys I'm sure this has been covered before but I will ask anyway. I did a search and really didnt find what I was looking for.

My 70 2wd has a small block currently... I got a smoking deal on a 454 built big block. I know the motor mounts and radiator will have to be changed.

Can I use the 396 motor mounts or???

Is there any cross member changes ect..

Can I buy a conversion kit?

Thanks for the help guys!!

[prostreetC-10]

I went from a 250/sm465 to a 460/M-22. Mine about fell in and I had the correct stands. I would thing yours will be just about as easy except for small stuff. I'm guessing trans mount will be just about the only thing to play with and that a small one.

Actually, in looking at your sig, you already have a TH400. Seems like mine had a few different holes on the frame rails. You can use the X member you already have. I just don't know if you will have to relocate it. I would guess not.

[Chrislidgett]

I'm hoping it will be almost drop in... I just need to find out what mounts I need/can use. the big block is a 79 block.

[prostreetC-10]

Block doesn't matter. You just need the correct stands for these year trucks. They are not cheap used.

[Chrislidgett]

by stands are you talking about motor mounts?

[prostreetC-10]

To me, the mounts are what attach to the block and the stands are what attach to the frame. The mounts then attach to the stands.

[Chrislidgett]

gotcha so another stupid question. Is the mount that goes to the block the same no matter what the block size? or can those be different?

[prostreetC-10]

I "believe" it doesn't matter about block size rather year of the project. Some of these trucks use a clam shell on the frame and you need the correct mount. I know my '68 used a stand and a different mount because a big bolt went up through the inside of the stand and screwed into the mount. A PITA at times. I think the later trucks like mabye a '71 or '72 have the clam shell on the frame and a mount where a bolt runs though both mounts and has a nut on the end like a Camaro and most other later model rigs......if that makes sense.

[c1069]

You can use 68-71 stands

72

tubular aftermarket

BB TH400 linkage


4 core radiator

[chevytruckluver]

dont want to bust your bubble... dont run the turbo 350 transnission behind that big block, it wont last. you need to find a 400 turbo for it. This will also require a drive shaft yoke change.
Also factory used the big hump floor for TH400, but I have seen guys put them in the small hump floor, its a little tighter
good luck!

[prostreetC-10]

Look at his signature. He currently has a TH400 behind the 350 sbc.

Nice try Mr. "bubble buster meany"!! lol

[chevytruckluver]

opps, but hey thats a good thing!

[prostreetC-10]

One less part to get. You are right about the TH350.....especially behind a 454.

Cool avatar

[Chrislidgett]

Here is what is currently on the truck....

Are these the correct stands then?




Posted via Mobile Device

[ItsRandy]

Not the right stands but you can still use them, I did when I put a big block in my small block truck.

[prostreetC-10]

They are the correct stands for a SBC.

Randy, did you run into any issues you had to overcome? Are the SBC stands taller?

[Chrislidgett]

Do u have headers randy...how did you overcome the sixe difference?
Posted via Mobile Device

[ItsRandy]

Originally Posted by prostreetC-10

They are the correct stands for a SBC.

Randy, did you run into any issues you had to overcome? Are the SBC stands taller?

The only thing I remember is the headers were real close to the stands. When I did the swap I didn't know there were different stands for big blocks (ignorance is bliss), I just stuck 'er in and bolted 'er up. Drove it like that for 18 years.

[ItsRandy]

Originally Posted by Chrislidgett

Do u have headers randy...how did you overcome the sixe difference?
Posted via Mobile Device

I had Hooker Super comp headers. As I said in the last post, the headers were real close to the stands. When I took the truck apart for the frame off rebuild there was a dent in the #1 header tube where it was hitting on the engine stand. These were pretty small tube headers (1 7/8ths I think), the headers I have now would not have fit with the small block stands (I bought big block stands).