Originally posted by dmc12mk3
Fitting a big block in a tri-five usually requires the side mounts. No worries as most kits are a bolt in affair. If I recall, I think the six cylinders used the spots where the side mounts go. It also requires the six cylinder radiator mount as the v8 mount places the radiator on the firewall side of the support that goes from fender to fender under the hood. The firewall will require some massaging with a hammer, which is not too bad. Jegs sells the headers you will want for this. The main thing with the headers is the ability to clear the steering box. Another reason to go with the side mounts is the torque you'll be making with the big block. I recomend using the turbo hydramatic bellhousing mount kit available from classic chevy part # 10612 (~70 bucks last I needed one) as well as some form of rear tailshaft mount. This will allow you to run a later model bellhousing with out any issues aside from how you're going to actuate the clutch. I've used a vega/monza cable style on the cheap, but a hydraulic throwout bearing type setup would probably do for ya if clearance is an issue. The reason for using the three mounts is simple, the side motor mounts and bellhousing mounts will take just about any amount of torque you can throw at them. The tailshaft mount is just to keep the transmission from jerking to the passenger side when the tires catch. At which point your new goal will be to eliminate wheel hop from the rear suspension.
You'll want a 5/8's fuel line too if you don't already have one put in.
edit - btw, the headers you will want are $220 bucks from jegs with 1 7/8s primaries. pn - 737-h8023
ooh - looks like they have some super competition headers too
2 1/8's primaries - pn 520-2227 $400
the 6cly. used the same style front mounts as the V8, they were just closer to the rad. my 56 had a bbc in it at one time and they used the 6cyl. mounts to fit it. most of the side mount conversion will move the motor forward enought to eliminate having to clearance the firewall. it depends on what box your using, stock or 605 box or rack and pinion, to know what headers to use. i`m not sure about those 1 7/8 tube headers but i know the 2 1/8 are for using the stock style front and rear mounts. always ask the tech guy or manufacturer if they will work with your mounts.
the 5/8" fule line is way too big. a 3/8 or 1/2 would be plenty.
there are also a few companies that sell 4spd linkage for bbc motors. just look at the different kits before you buy one and make sure it will work for what you want .