Questions on early induction and exhaust

[John Fitzpatrick]

This photo of an early car has a different intake and exhaust configuration from what is commonly seen. Can someone shed some light on whether that’s a muffler or perhaps a support for the “luggage box”? If it’s a muffler, why would it appear on a ’65, well before the road cars were produced?
Also, the intake heat shield is different from the turkey pan style box. Did it mate up with a plenum within the rear body?
Thanks for any light you can shed on this.
John

The photo is from The Ford GT 40 Prototypes and Sports Cars, David Hodges, Arco Publishing, Inc. New York 1970

 

[Lynn Larsen]

John,

That is a VERY early picture as it has the Colloti transaxle fitted. This would certainly be '65 at the latest. I would speculate that the difference in the turkey pan is going to stem from the fact that the Colloti is there by causing the engine to be in a higher position. So, the flat (no sides) turkey pan is level with the rear deck.

I can't answer the question on the common cavity silencer though.

Lynn

 

[colin artus]

The difference with the pan is it is mounted between airhorn and carb body, as opposed to the later pan which goes between carb body and manifold. Although this early style is easy to fab it does not shield the whole carb from engine heat.

 

[Lynn Larsen]

Good catch Colin, I hadn't noticed the pan position relative to carb/velocity stacks. They would have had to been wee little airhorns, wouldn't they? LOL

 

[Jac Mac]

The tailpipe's are megaphones ( enlarging in dia from collector to pipe end ) and the 'muffler' is really just a chamber over the tailpipes. I dont know if the chamber was open to both pipes or if the pipes were perforated,louvered etc where they pass thru. Ford was developing the 'INDY 256 cu in pushrod'- and later the DOHC motor around the same time and a photo of the evolution of the final exhaust for these cars is very similar to this exhaust system (sans 'muffler' of course ).

Also have a pic of the same car from side on with the rear clip raised. The airhorns dont appear much different to later versions.

Lynn, I thought 'wee' was a Kiwi only expression!

Jac Mac

 

[Lynn Larsen]

Jac Mac, I thought it was Scottish in origin. ;-)

 

[John Fitzpatrick]

Could this particular car have been something of a demonstraton vehicle, driven on the street or at shows? The tires look like rain or even street tires, and that would explain the muffler.

 

[Jac Mac]

Could this particular car have been something of a demonstraton vehicle, driven on the street or at shows? The tires look like rain or even street tires, and that would explain the muffler.

All the pics I have suggest that this is GT/101 which spent some demo time in both UK/USA before being pranged at Le Mans Trials.
Tyres look like Dunlop race tyres of that era, slicks had not arrived on the scene yet.

Jac Mac

 

[John Fitzpatrick]

Thanks for the info Jac Mac-- I had just assumed slicks were in use then. Sounds like the muffler allowed the car to appear at off-track events without being obnoxiously loud. Do you know if the megaphone tailpipe was effective? I like the overall look- does anyone know a commercial outfit that produces something similar?

 

[Jac Mac]

A bit more info would suggest that this is the 256ci alloy block pushrod indy motor in this car as the 289 did not see competition in a GT40 until Reims in July of 64.

John, any competent race bike/car fabricator should be able to make you up a tailpipe system like that, just dont go down to the local muffler shop, they are likely to make it back to front!

Jac Mac