I have read the threads from searching and havent found my answer.

I have a custom tubular cross memeber that was made for the car.

Ques... Will this still work with the BBC or will the BB change the position the trans sits in?

I have read the stock SBC motor mounts will work?

I know I need different headers. With those headers is it a must to move brake lines behind the frame rail?

I assume I will need BB springs?


I have heard alot of Beating the trans tunnel, and trimming the A arms down. Will I have to do this? Thanks for any help. I want to do this swap tonight.

 

Transmission position doesn't change with an engine swap. The SBC/BBC engine mounts are in the same position. Because of the larger bore spacing of the BBC, the block is longer and the extra length goes forward.

The cheapest swap headers are Hooker Supercomp but they're also just a small street header not good for much above a 454. They have 1-7/8" primaries and 3" collectors. Expect to pay at least $1000 for a good performance header.

Brake lines can stay where they are but when I first installed a BBC in my car, I relocated the brake lines to the other side of the steering shaft.

You don't need "big block" springs. You need springs with a spring rate enough to carry whatever the weight is that's sitting on them. A BBC with aluminum heads and an aluminum intake doesn't weigh much more than a factory SBC.

Why would you have to modify the transmission tunnel or A-arms to swap an engine? The engine doesn't go anywhere near them.

 

I wanted to swap the BBC in my 69 Camaro but the SBC to BBC swap requires me to move the Pass side motor mount over an inch. The trans wouldnt sit where it would with the BBC in the car. I figured I would ask to see if the same thing applied with my third gen.

I was told that I would have to shave the A arms for the headers, and I might have to replace the Cross member for the BBC.

I will probably have to get different springs as The car has Eibach now and is pretty low. Since I have cast heads on this motor that wont help. What is the spring rate on sock springs?
Thanks, I will go out to the garage and start the swap.

 

SBC mounts will have the engine sitting up slightly higher. It's not a big deal since the hood will need a cowl anyway to clear the air cleaner.

The only reason you would have to shave the a-arms is if you have some non standard headers or anything else.

I have 2-1/4" primary tube headers and a tubular k-member and a-arms. The heads have raised exhaust ports. I had to dent a couple of header tubes to clear suspension components because my configuration is nowhere near stock.

As with any non standard engine swap, some fabrication may be required.

Stock springs have many different spring rates. Depends on the original engine, depends on the suspension package. A V8 car like an RS can have soft springs while a Z28 performance package can have stiff springs. I ran lightweight V6 springs in my car for a few years.