- Going from Single Brake master to Dual brake master, using a proportiong valve etc.
You only use a Proportioning Valve if you are running disc brakes. This is because disc brakes require 1,500, to 3,000 psi to operate: but drum brakes only need 850 pounds to operate. Without a Proportioning Valve the rear brakes would lock up instantly at the first tap of the brake pedal. I recommend an adjustable one to get the ratio correct for your car's brakes, weight and suspension.
- Power steering bracket choices OE or Aftermarket, small block does not fit big block
- Power steering lines, SB are not long enough
BBC is a truck engine. It is much bigger than a SBC. Every other GM car engine, and all other car makes use the same size engine for a small block and a big block.
Because the engine is physically bigger it requires it's own brackets (there are four that fit and three that don't). Despite what I said above you can not use SBC accessory drives on a big block. I think in terms of accessories as going with the engine when I buy it (complete top to bottom and running at point of sale).
I generally use what was on the rebuildable engine core when I buy it out of the junk yard. The only exception to this is V-belts. V-belts are dead. The manufactures no longer routinely make them. They are made only in small batches once a year or once every two years, or not at all as not all belts are being made now. Most of the V-belts sold on line are fractional horsepower belts made for lawn mowers not cars that rev four to five times higher than a lawn mower engine can rev.
I use serpentine belts (two not one) to drive everything. This is because you can not throw a serpentine belt the way you can a V-belt. They also transmit more power without slipping. The more ribs in the belt the more power they will transmit. I use aftermarket billet seven rib aluminum pulleys from March or Zoops along with their brackets to mount them.
There are power steering brackets made for a BBC with a short water pump. (1965-'68)
There are power steering brackets made for a BBC with a long water pump. (1969-'84)
There are power steering brackets made for a BBC with a long water pump and one or two serpentine belts. standard rotation pumps and two serpentine belts where used from mid 1984-'86, starting in 1987 all water pumps are reverse rotation and have one serpentine belts with two or more idler pulleys.
- Making sure you have the correct driveshaft, crossmember, and flexplate, when coverting transmissions
This has nothing to do with the engine, it depends upon your choice of transmission. All GM engines use the same transmission dimensions, Chevy is different from BOP trannies, but share some of the overall dimensions but could differ even within the same family of transmissions. The transmission is mounted in the same place (relative to the back of engine), and uses drive shafts that match the transmission (spline count and length).
The transmissions themselves all have different transmission mounting points (distance from the face of the bell back to the mount), and different overall lengths (from bell mouth to rear seal). They also may have different input shaft lengths and spline counts as well as different out put lengths and spline counts depending upon torque rating.
If you used what the factory used originally then parts are available used or as a reproduction part to fit and install it easily. If you don't then you have to buy or make cross-members and adapters to fit the transmission.
You can use a 153 tooth flywheel (or flexplate) on a big block and the engine will crank up and run just as well as it will with a 168 tooth flywheel. The engine could care less what happens to the energy it makes; or what is bolted to the crankshaft flange. If you don't mind your ten and a half inch clutch slipping and burning up you can use it behind the more powerful big block. The engineers designed the eleven inch clutch (and flexplate) to fit behind a BBC to offer more friction area to prevent the clutch slipping.
- Engine mount towers and engine mounts. Tall and skinny or short and wide.
Tall and skinny or short and wide is due to a safety recall caused by Ralph Nader to address the problem of broken motor mounts.
The 265 SBC used four mounting points. Two on the front and two attached to the cast iron bell housing that also was where the starter bolted up. Starting in 1958 with the introduction of the X-frame cars the motor mount was bolted to the side of the block and GM made their own three speed (Saginaw) that had a transmission mount on the back of the tranny.
In 1968 the federal courts decided that GM had to change the motor mount to prevent engine torque from pulling them apart. This had been done since the 348 was introduced and all engines that made more than 300 horsepower from the factory required an interlocking engine mount (the Corvette retained the four point engine and tranny mount up until 1965 when the BBC caused them to go to a three point mount). The 275 horse 327 in a heavy car (or if little Johnny borrowed mom's car) had enough torque to break the motor mount, and often did prompting the law suit.
The tall and narrow mount was used from 1958 through 1968. After the recall (and everyone having a five ton steel cable torque strap wrapped around the upper control arm mount) Chevy went to short and wide motor mounts on 1969 through 1972. The two mounts do not interchange, even though you can only buy the correct tall and narrow through a reproduction reseller as the corner auto parts store only sells short and wide motor mounts which as I said won't fit a 1958-'68 car.