bbc in a convertible

[blown1955]

hi is there any problems or tricks fitting a 454 in a 55 ragtop?

[joninomader]

The only problem may be the X frame. Might be a little more work to get everything to fit.

[Chevynut]

A convertible frame is the same as any other frame from the x-member forward, and all the sheetmetal is the same. I don't know why you'd have any more issues putting a BBC in a convertible as in any other model. As mentioned, your choice of transmission may be an issue with the x-member....but it has nothing to do with installing a BBC.

[CharlieC]

Nothing that time and money can't fix. :)

My Gen IV block and T56 wouldn't work with the stock x-member (too long), but folks seem to have better luck with auto's it seems.

Pick whatever motor-tranny you want, and I wouldn't blink an eye to cut the stock x-member out and replace it with either a Progressive or Art Morrison item.

Charlie

[Chevynut]

Pick whatever motor-tranny you want, and I wouldn't blink an eye to cut the stock x-member out and replace it with either a Progressive or Art Morrison item.

Charlie

I dunno. If I was going to do that, I'd buy another frame to modify and sell the convertible frame instead of cutting it up. ;)

[CharlieC]

I've been talked into or talked myself into doing alot of stuff I wasn't planning on. But, if all you need to do is fit a tranny, a $300 x-member kit is a far cry different from doing a whole new frame swap.

Then again, if you can build your own frame, well... :)

Charlie

[blown1955]

i think i will run a t350 trans as i have already put the rear and side mounts in for a small block,so the trans should be in the same position.

[Crafty]

is this a convertible frame ?

http://images1.americanlisted.com/nlarge/1955_1957_chevy_convertible_x_frame_7814828.jpg

if so, no problems.. the trans should fit before the center of the X, you build a trans crossmember that spans the gap between the members of the X rather than going all the way to the frame.

[Rick_L]

That used to be a convertible frame.

Some transmissions' length (700-R4 and T56) will get very close to the cross of the X as Charlie said.

[CharlieC]

Sure you want to use a TH350 behind a BBC, and are you sure the mounts are all in the same location? I wouldn't think so, given the BBC is longer, isn't it? Firewall problem?

Several of the parts suppliers make a mount for TH350/400 that connect to the sides, close to the middle of the "x".

Charlie

[Crafty]

That used to be a convertible frame.

Some transmissions' length (700-R4 and T56) will get very close to the cross of the X as Charlie said.

yeah they do get close, this is the sort of thing I mean :

the grey "ears" are made from 1/4" plate, they sit on the underside of the X (completely covering it) and are bolted through it, both inside and outside of the X.

The red bar connecting them this thickwall square box section, welding to the ears. The blue rectangle off of it is again 1/4" and its gusseted as you'd expect. the mount bolted to the underside of the box sits on this and is bolted through the hole in it.