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Rollzz 06-27-2013 07:23 AM

Rolls Royce Chev Conversion
Greetings Gurus from Down Under
I have a 69 Rolls Silver Shadow that I've been collecting parts for to convert to a GM ZZ383. Plan is to hook it up to a GM cased Turbo 400 so that I can retain the electric shift of the Rolls version of the Turbo 400.
At the present moment I'm planning out what to do with the Rolls braking system. Rolls Royce use a similar power boosted hydraulic brake system as the early citroens where a couple of camshaft driven hydraulic pumps charge nitrogen filled spheres. This stored pressure is then diverted to the dual front twin piston calipers as well as the rear 6 piston units when the break pedal is depressed giving you your braking system.
Of course changing engine to a small block looses these pumps so hence I'm looking for advice on anyone that has undertaken such a swap so that I can retain as much as the Rolls System as possible.
My initial thoughts as follows:
1. Use a Citroen DS hydraulic pump (belt driven) and plumb this up to the Rolls Royce accumulators, retaining the rest of the braking system as std. Theoretically the DS system works at the same pressure and also uses the same type of brake fluid.
2. Ditch the Rolls pressure system and set up an underfloor master cylinder with remote mounted VH44 type booster and plumb this up to the standard Rolls calipers. Understand that the Rolls Calipers have huge pistons so sleeving down the caliper bores to a smaller size so that adequate feel and travel of the brake pedal is achieved.
Apologies for the long post but just looking for any feedback from anyone that has some ideas on sorting the brakes.

killeratrod 06-27-2013 08:09 AM

try this site out they maybe able to help out.

Rolls-Royce and Bentley

also try this out i did a simple search on google type in rolls royce chevy motor

Don Meyer 06-28-2013 05:34 PM

I am using a hydroboost on my 66 rolls w/a sbc & fabricated frame.


Rollzz 06-29-2013 06:43 AM

Hey Don,
Slick Shadow you have there. Kudos to ya. Was thinking the full frame option as a last resort and the more I think about it, the more sense it makes as the Roller body and rear end flexes quite a bit when putting power through it.
I note you have gone with a live axle rear end instead of an independent set up. Is there room in the rear floor area to still have decent suspension travel and to accommodate movement of the diff housing?
I've also checked out the hydroboost option. Are you still running the floor mounted pedal box or rat trap or did you go for a firewall mounted set up?
Also interested in what front frame you are using to retain the same track as the Roller.
Thanks heaps

MARTINSR 06-29-2013 08:55 AM

What transmission does your Rolls have in it originally? I believe they had a Buick Nailhead ST400 which is a TH400. :D


Don Meyer 06-29-2013 05:27 PM

1 Attachment(s)
I am using a 700r4 trans......Do not remember the auto that was in it. It's sitting on a highly modified GM
frame(G body) . The rear is a modified g body 4 bar w/a 9" rear.

I am using a corvette master under the floor.

I have not completed the car, but am about ready to finish.

Rollzz 06-29-2013 11:39 PM


Originally Posted by MARTINSR (Post 1689634)
What transmission does your Rolls have in it originally? I believe they had a Buick Nailhead ST400 which is a TH400. :D


The Rolls auto in the Silver Shadow is essentially a GM TH400 but has a different front bolt pattern. Internals are virtually the same bar some machining of the case to improve shift quality. Back in its heyday GM Powertrain manufactured these trans with a universal circular bolt pattern and supplied these to Bentley, Rolls Royce, Jaguar, Ferrari and others who made their own adaptor housing between their engine and the GM trans.
I have seen a crowd in the US that makes an adapter between the rolls trans and the GM engine but I'm not a fan of running spacers etc between flex plates torque converters etc as has seen way to many of these fail. Benefit of this method is that it still uses the Rolls adaptor housing where the trans is mounted as they don't have a crossmember at the rear.
Other options are to run a heavy duty GM bellhousing case as the drag racers do that requires you to cut the front part of the RR case at the pump to bolt the new Belhousing to or swap the case entirely with a GM case. Doing so will however require rear engine mounting brackets for the SBC that line up pretty close to the original rolls mounts.
Sounds like a lot of mucking around but the benefit is that you can retain the RR electric trans shift on the column which is such a great lazy mans feature once you have used it.

MARTINSR 06-30-2013 08:14 AM

Exactly, they were NOT a "universal circular bolt pattern" they were a Buick Nailhead transmission!

Here is a ST400 from a 1964 Buick Riviera with a 401 or 425 nailhead.


Don Meyer 01-31-2014 07:21 AM

My Rolls is now driveable...I ended up with a vacuum booster(on the frame)/ chevy crate motor(350)
a 700r4 trans/ford 9" rear end.
The suspension is all g body(global west A arms). The frame was made from 3" x 5" tubing. The interior twas redone in leather(peanut color-body is black).

Anyone wanting more info just

Don-Central Florida

MARTINSR 01-31-2014 07:26 AM

How about posting some photos Don!


Don Meyer 01-31-2014 12:06 PM

I'll do that when it stops raining.......Don:)

techinspector1 01-31-2014 12:18 PM

Don Meyer is a fabricator of the First Order. I'm familiar with his work and much could be learned from him. He certainly has my respect.:thumbup:

Don Meyer 01-31-2014 05:35 PM

Thank-you....that post make my day:)

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