race car designer question

Can anyone tell me the name of a designer at Brabham, Motor Racing Developments, at or about the time when Jack was gone and Ron sold to Bernie E.
Geoff Ferris is often listed as the designer of the last few Branham customer cars, built under Ecclestones ownership, the only production Brabham monocoque chassis, the BT38 in F2, F3 and F Atlantic or FB trim followed up by the BT40 in F2 and F Atlantic/FB spec as well as the BT41 for F3 and several ran over here with Cosworth 1,100 cc BDJ motors.
I well remember Geoff Ferris is credited for both but in the back of my head is he did the BT38 range but another designer was really responsible for the BT40 and 41, which had similarities to the BT38 range but were substantially different in important areas.
I think it was a guy who went on to design many other racers, maybe even Indy cars, but I simply can't dredge up the name.
Actually I am all but sure the man I am thinking of became an Indy car designer of some renown, maybe doing cars for March or Lola or Penske in the mid 1970's.
Any help appreciated......I will recognize the name as soon as I see it.

I think Ralph Bellamy and Gordan Murray were there at that time

I may have answered my question through close examination of the great book "A- Z of Formula Racing Cars 1945-1990" by David Hodges.
I now believe the name was Gordon Fowell, a relativelu under the radar designer.
His "credits" include such greats as the Amon AF1 short lived Formula 1 car that started but one F1 race, Spain in 1974, only to FNF, as well as the alternative to Alan NMcCalls Tecno F1 car, the Goral E731, which is described as "hopeless". Amon was of course also connected to the Tecno F1 initiative.
He was responsible for the Sana F Atlantic car in the UK of which it seems one or two may have been finished and if memory serves the car was based on the BT40 design.
Maybe Mr Fowell assisted Geoff Ferris in updating the BT38 to BT40 specification ?
I plan on posting on 10/10ths site, if you are not familiar plan on spending significant time.
One of the forums is The Chassis History thread, if interested you can get lost for days, alphabetically by make and numerically by model number, chassis history and minutiae you will be amazed at the detail, incredible for research.
Bellamy and Murray of course were central and made exceptional designs but mostly if not all Formula 1, not the production lesser classes cars.

Answered my own question.
For both of you readers who may care, Gordon Fowell had nothing to do with any Brabham, not the BT40 or any other.
His claim to fame, such as it was, he passed away over a decade ago, was the ill-fated Amon AF1 Formula 1 car that Chris qualified but once, Spain in 1974 and resulted in a DNF.
He also was the designer of the Alan McCall replacement Tecno F1 car, oddly numbers the Goral E731, with a Tecno Pederazzini flat 12 motor, the oackage described as "hopeless" and never raced.
N
But he was also responsible for the pair of Sana F3/Atlantic cars, one of which was destroyed in a shop fire, the other converted with a Rover V8 for hillclimbs and F Libra racing.

Meanwhile, the actual designer of the after Ron Tauranac Brabham but the cars still called called Brabhams, built by Motor Racing Developments which is what the chassis tag on my BT40 says, only monocoque customer cars the BT38 range for F2, F3 and F Atlantic/FB and the BT40 for F2, F Atlantic and FB as well as the BT41 for F3 and SCCA FC . This line of cars was indeed done by Geoff Ferris, who designed the Penske PC1 and PC3 and PC4 [the PC2 was a March 751 heavily modified by Ferris in the Penske shops] and the PC4 was the car John Watson won with in Austria for Penskes only F1 win.
So it seems Geoff Ferris went from Motor Racing Developments [Brabham] designing customer cars for the smaller categories directly to work for Roger in 1973-1974.
The BT 40 was a 1973 car and Mike Hall drove the first in FB/Atlantic trim over here in November 1972 at Rd Atlanta in the Runoffs finishing 5th in a brand new car and the first BT40 to race in NA. Mike raced a BT40 throughput 1973 and 1974, finishing 2nd at the runoffs in 1974 about .5 second in front of me in my BT40 while Ken Duclos won for the second year in a row in his, now mine, BT40. Black-red-yellow, pretty sight.