'68 shortbed BBC swap questions

[FstCarsNGuitars]

First off I'm aware there are several threads in regard to swapping a big block in our trucks but I have a few questions that I can't seem to find answers to. I'm currently wanting to find out if the perches I have will work or not (I will post a pic) I seem to be getting two different answers on this. I've been told that my current towers will work as long as I'm using tight clearance headers. I've also been told that I would need to find '72 and up perches to use stock mounts. My dilemma is that I want to build on a budget, so if I can use stock mounts, I will. At the end of the day if I need to dish out the money for aftermarket mounts, I will...just want to know what choice would benefit me better.
*Also, if the perches I have will fit, what mounts will work?

Any help is appreciated guys, thanks!

[67ctener]

People put bb on sb mounts. Not sure what is involved to do so but they make it work. I know for sure you would need a low stock height valve cover. Keep an eye out and you can come across bb mounts for a reasonable amount. The correct way would be on bb mounts and Sanderson bb8 headers. As far as I know they are the only specific headers for our trucks.

[69SCSS]

BBC stands are shaped different. They have more room in back for exhaust clearence, I'm not sure if you'd have to clearence them to make it fit. You can use the same SBC mounts on the BBC stands, which is what I did. There are many threads here about doing the sway, look up tx_firefighter as the author of the post.
You don't have to use the '72 only super expensive mounts, they isolate better though. I know you can use the '73 and up if you add some spacers to the top of the frame rail, since the '73 and up frame rail is taller.

If you're on a budget though just find some good condition 67-71 BBC stands and use cheap SBC mounts and large washers. Check out my build thread and do a search for the other thread I mentioned. Hope that helps.

[kelsfine69]

The mounts that go on the block are the same. I used 69 BB perches on the frame but in the small block frame location. Since it was a small block truck I didn't want to move the trans and re-do the driveshaft.Headers are Hooker Super Comps

[kwmech]

As mentioned the big block stands are shaped different and when bolted in the same place as the small block stands they actually move the engine rearward 1.25'' and they allow room for the cast iron exhaust manifolds. The big block cushion is thicker than the small block and has an additional cushion underneath which interlocks with a 1/2 bolt to keep the engine in place under extreme acceleration. You can bolt the big block on the existing stands, but watch out for fan clearance at the radiator with either water pump set-up you use and may have to go to electrics.

All in all, spend a little extra and get the correct parts, you'll be happier in the long run and it'll make for a nicer conversion

[seafoam68]

My experience was that factory big block mounts are very pricey. What I did was to use the mounts from the 80's model big block donor truck. These are basically just a straight piece of metal on an angle from top of frame to top of crossmember. I believe 3 of the 4 holes even lined up. I used Sanderson shorty headers and there is all kinds of room. What I have found by building on a budget is don't be afraid to modify a little and think up ways of doing things. Just make sure to keep it safe. Good luck.

[FstCarsNGuitars]

Originally Posted by kelsfine69

The mounts that go on the block are the same. I used 69 BB perches on the frame but in the small block frame location. Since it was a small block truck I didn't want to move the trans and re-do the driveshaft.Headers are Hooker Super Comps

Are the 69-72 bbc perches easy to come by? I've been having trouble finding them anywhere.



*You guys are awesome, thank you ALL for the info I have so much to learn lol.