Thread: 56 chevy small blk to big block?

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Anyone done this conversion? Maybe in a 55 or 57? Will it just drop in? Will it hit the firewall? My HEI on my 283 barely takes a credit card behind it. Its that close. Want to step up to more torque. Always wanted a big block. Will be swapping mine out soon and although the 383 is really ok, want the big valve covers! Any input would be appreciated.

it can be done. i think the stock steering box is close. the room at the back of the block would be about the same place. but it would be more engine so thing like the rad will need to be re work like the be cool kit for the rad and i am sure some one makes headers i have a nice 402+.040 big block hyd roller engine that needs a new home?

Still interested if anyone has any info about this. Any books, or articles that anyone knows of. Want to put a big block in. Have found companies that pull the motor 2 1/4 inches forward, 1 1/4 inches forward. Need to know which headers clear etc. Any info would be great. Think I've decided on the zz454. Thank you...

First, get the conversion kit that converts the mounts from pin mounts in the front and bellhousing mount and changes it to the side mounts. A number of companies make headers for the swap, Hooker has a set. Not sure oabout firewall clearance on the HEI, might have to rework the distributor notch in the firewall a bit for clearance. Also, if my feeble memory serves me correctly, the radiator has to be mounted on the front side of the radiator support... Not a real tough swap as long as you get all the right parts.

I heard on the tri 5's the radiatior was mounted on the front side of the core support for the V8's I think and on the back side for the 6cyls, maby it was the other way around.

Just saw a '55 in a local show, had a BBC and the radiator (a humongous aluminum unit) mounted in front of the core support. The owner was elsewhere, so I couldn't discuss the car with him.

Matt, the stock 5'ers had the radiator in front for a 6, in back for a V8.

makes sense, the 6 is longer by 2 cylinder lengths or so. thought I had it backward just wasn't shure. thanks for correcting me.

i put a 348 motor in a 1956 chevy. in 1960. used the stock manifolds , but had to grind them down so the steering wouldn't hit. used the side motor mounts, move the radiator, and knock the fire wall in a little for the dist. to clear. wasn't that hard of a job.