CHEV 3800 GT

User avatar
sixpak
Posts: 404
Joined: Sat 12 Jan 2008, 07:12

Re: CHEV 3800 GT

Post by sixpak » Fri 11 Mar 2011, 20:53

Fascinating read....best thread EVER!!! I'm sitting with bated breath waiting to find out if the race Can-Ams ever used the twin 4-barrel crossram intake manifold for any reason whatsoever like the Penske team some years previously in the SCCA series?

993 Kadett
Posts: 64
Joined: Sun 16 Dec 2007, 13:33

Re: CHEV 3800 GT

Post by 993 Kadett » Sat 12 Mar 2011, 10:24

Hi Sixpack - In answer to your Q ... no we never did use the cross ram manifold. Whilst considered at the time, there were three things which mitigated against its use and it never was considered seriously. Firstly availability... production of the part had ceased around 1970 and there were insufficient parts in the system to do the job. Secondly we were forced to use an as built factory inlet on the race car, unlike the Penske cars where the regs allowed homologated dealer options. The cross ram set up on a street 302 was a nightmare in that we already had an engine that lacked bottom end torque with a single four barrel....the dual set up just made that worse. I guess we could have lived with that but Basil correctly knew that the 450bhp (approx) available with the stock 4BBL Manifold would be good enough to do the job.
Also worth mentioning is the fact that time pressure to get the cars built was another ever present issue.The project hung on a thread with the availability of the 302 engines. At one stage it was even considered that 350 LT1 engines would be rebuilt in the Aloes engine plant using 302 pistons and cranks purchased from GM parts and accessories division in the USA. That turned out not to be necessary..... as our friend UNCLE BOB again came to the rescue. Scores of transatlantic phone calls resulted in favours being called in and the Tonawanda engine plant produced a differential parts list for both the then current 350 LT1 and the '69 spec 302. The unique 302 parts were sourced from the US GM P&A dept, shipped to Tonawanda and a special run of 302's happened in late 1972 specially for SA!
At the same time, the first production car was being readied for build to be used as the Engineering prototype (arse about face but the only way the first production bodies could be checked out was before the engines arrived.) The first production car came off the line without an engine and was shipped to engineering where the simultaneous processes of production trial & engineering protype happened as soon as the 302's arrived. Again, as soon as the basics were checked out, that first car was shipped to Wynberg for the dealer team.....it eventually became the 1972 9hr car & 1A. With the arrival of the 302's, a second prduction trial car was built and it arrived in engineering at about the time the first car left for the Dealer Team. This car was used to do the proper engineering validation. We had the absolutely unprecendented situation of the production trial, engineering prototype finalisation and the first racing car happening at the same time. Full production had not yet started.
The point here, is that for all the criticism GM should take for the lack of vision, its engineering capability when turned on, was astonishing.... and the man that got all this done was Jonny Pittaway, the cornerstone man of the production car and someone whos name is, sadly, hardly ever mentioned. P

User avatar
ZA Perana
Posts: 7313
Joined: Sun 15 Jul 2007, 18:01
Location: Cape Town

Re: CHEV 3800 GT

Post by ZA Perana » Sat 12 Mar 2011, 19:45

Here is a question....much was made of the fact only 103 engines were brought in for use, surely parts were also brought in for dealer support should an engine for whatever reason a new block or suchlike? Or did GM back then do the same as they do now with the Lumina and keep next to zero parts on the shelf for "in case".

I am pretty some customers did break things and if there were such a finite supply of parts surely this would have lead to the demise of many cars?

Strange question I know! :)
Alfa GTV 3.0
Ford Capri Perana V8
Chevy Lumina Supercharged

Wait not for tomorrow to do what can be done today, live each day for one knows not what the next day may hold.

993 Kadett
Posts: 64
Joined: Sun 16 Dec 2007, 13:33

Re: CHEV 3800 GT

Post by 993 Kadett » Sun 13 Mar 2011, 15:42

Jacques. in fact parts availability was very good , and with most of the parts being either Firenza based for the body & trim or Chevy small block for the associated mechanicals 95 % of the Can Ams bits were normal stock parts anyway. At the time, the parts dept kept stock of all unique stuff and surprisingly little parts turnover on the mechanicals. I should perhaps explain that the drivetrain... Engine, gearbox & axle were hopelessly overengineered for the application. The 302 engine was the 69 spec unit with fully floating pins and the 350 four bolt main block. Gearbox was the M20 specced for engines up to 396cid and the axle, designed by GMSA engineering, was based on the model 75 Borg Warner normally fitted to the Constantia. In its applicating in a 1100Kg Firenza that combination was effectively unbreakable. Two transmissions were homologated for the car, the production, wide ratio 3rd, M20.... and the close ratio "Rock Crusher" M22 used on the race cars.
The decision to use the M20 wide ratio box on the road car was made simply to make the car more driveable in the lower gears,.... for info a comparison of the gearing and effective max speeds on an otherwise stock Can Am

Factory spec M20 Max @ 6200
1st 2.52 102kmh
2nd 1.88 137kmh
3rd 1.46 176kmh
4th 1:1 245 @ 5900

M20CR/M22 Max @ 6200
1st 2.20 117kmh
2nd 1.68 153kmh
3rd 1.28 201kmh
4th 1:1 245@5900

We had a close ratio conversion for the M20 which involved changing the input shaft and counter gear only and made a M20 into a M21 with the same ratios as the above M22. P

User avatar
ZA Perana
Posts: 7313
Joined: Sun 15 Jul 2007, 18:01
Location: Cape Town

Re: CHEV 3800 GT

Post by ZA Perana » Sun 13 Mar 2011, 16:08

993 Kadett wrote:Jacques. in fact parts availability was very good , and with most of the parts being either Firenza based for the body & trim or Chevy small block for the associated mechanicals 95 % of the Can Ams bits were normal stock parts anyway. At the time, the parts dept kept stock of all unique stuff and surprisingly little parts turnover on the mechanicals. I should perhaps explain that the drivetrain... Engine, gearbox & axle were hopelessly overengineered for the application. The 302 engine was the 69 spec unit with fully floating pins and the 350 four bolt main block. Gearbox was the M20 specced for engines up to 396cid and the axle, designed by GMSA engineering, was based on the model 75 Borg Warner normally fitted to the Constantia. In its applicating in a 1100Kg Firenza that combination was effectively unbreakable. Two transmissions were homologated for the car, the production, wide ratio 3rd, M20.... and the close ratio "Rock Crusher" M22 used on the race cars.
The decision to use the M20 wide ratio box on the road car was made simply to make the car more driveable in the lower gears,.... for info a comparison of the gearing and effective max speeds on an otherwise stock Can Am

Factory spec M20 Max @ 6200
1st 2.52 102kmh
2nd 1.88 137kmh
3rd 1.46 176kmh
4th 1:1 245 @ 5900

M20CR/M22 Max @ 6200
1st 2.20 117kmh
2nd 1.68 153kmh
3rd 1.28 201kmh
4th 1:1 245@5900

We had a close ratio conversion for the M20 which involved changing the input shaft and counter gear only and made a M20 into a M21 with the same ratios as the above M22. P
Very interesting...I read those geared speed with a big :D because launching a Cam Am at a set of traffic light with thatr lovely long first gear must have made it virtually unbeatable! Of course the interesting point is the LS diff in the Can Am and the one in the Perana seem to have very much in common...same final drive ratio as well as same clutch system, interesting co-incidence ;)
Alfa GTV 3.0
Ford Capri Perana V8
Chevy Lumina Supercharged

Wait not for tomorrow to do what can be done today, live each day for one knows not what the next day may hold.

993 Kadett
Posts: 64
Joined: Sun 16 Dec 2007, 13:33

Re: CHEV 3800 GT

Post by 993 Kadett » Mon 14 Mar 2011, 11:56

From memory the two cars both ran model 75 borg warners and the LSD is likely to be the same. The long 1st is something of a problem in that one had to be careful not to light the tyres too early, because that would result in a big cloud of smoke and not too much forward movement!. Best method to launch was to slip the clutch up to around 50 km/h then dump it. Not good for the clutch but 1/4 mile times around 13.00 dead at the coast. P

User avatar
CraigJ
Posts: 101
Joined: Tue 13 Jul 2010, 14:46
Location: Kuils River

Re: CHEV 3800 GT

Post by CraigJ » Fri 15 Apr 2011, 15:01

I was only born in '75, but I am loving these stories. Thanks for posting them.

993 Kadett, if you ever do start a blog, please let us know.
'93 Ford Sapphire 5.0
'07 Lexus IS250SE
'13 Ford Ranger 2.2 XLS DC

User avatar
FairmontGT
Site Admin
Posts: 2167
Joined: Wed 11 Apr 2007, 03:49
Location: Potchefstroom RSA
Contact:

Re: CHEV 3800 GT

Post by FairmontGT » Fri 15 Apr 2011, 16:35

I think we should help him set up some kind of website, or even better he should publish a book.
Yes we did build muscle cars in RSA!!!!
http://www.africanmusclecars.com

renier1972
Posts: 1
Joined: Thu 25 Apr 2013, 10:26

Re: CHEV 3800 GT

Post by renier1972 » Thu 25 Apr 2013, 10:39

I know this is an old post but I found I so interesting that I'm attaching a figmant of imagination just to show what could have been.
Cheers!
Attachments
Chev 4300 GT final.JPG
Chev 4300 GT final.JPG (56.25 KiB) Viewed 6916 times

pas-chill
Posts: 75
Joined: Wed 28 Mar 2012, 15:13
Location: Toronto, Canada

Re: CHEV 3800 GT

Post by pas-chill » Thu 25 Apr 2013, 12:33

I saw this at the Billings when I lived in England (2010)

Image

Image

Image

Image

Image

Image

I hope it's appropriate and doesn't dilute this excellent read.

Post Reply

Social Media

     

Who is online

Users browsing this forum: No registered users and 5 guests