vintage racecar question

[masraum]

Can anyone tell me what the point is for having the uneven stacks like you seem primarily on vintage racers?

[onlycafe]

so no stack is shortchanged of wind racing over them. and cause it looks cool man.

[nota]

the total track of the intake is = with the stacks
as some head casting ports are longer or shorter
so the stacks are different to correct and make the total run = and make each cyl put out the same power

[masraum]

Originally posted by nota
the total track of the intake is = with the stacks
as some head casting ports are longer or shorter
so the stacks are different to correct and make the total run = and make each cyl put out the same power

That makes sense, and now that you mention it, looking at the picture, it looks like there are 2 lengths. The angles make it seem like they are all different.

Cool, thanks.

Yes, it does look cool too.

[Joeaksa]

Look at the headers on cars like this. They match the length of the intakes AND exhaust to even everything out.

[75'930cab]

Yeah you see these on most of the Can-am cars at vintage events! Looks bad-azzz

[911pcars]

Originally posted by Joeaksa
Look at the headers on cars like this. They match the length of the intakes AND exhaust to even everything out.

The equal distances may be just a coincidence. The length of the header pipes is designed to extract the exhaust gases in order to maximize power at a certain engine speed.

Sherwood

[jluetjen]

Nota's got it. The aluminum "Porcupine head" big block V8's used in the CanAm had uneven intake port sizes. The nick-name and the uneven sizes are a result of the splayed valve design. They came up with the stack design shown because it filled in a big hole in the torque curve.

Here's a picture of the heads where you can see the difference in the port lengths.



Here you can see the splayed valve angle which prompted the nick-name "porcupine head"


Both pictures are from Pete Lyon's excellent book: "Can Am". It's well worth the money.

BTW - Anyone know if any sources for in-car CanAm videos? I'd love to see what it was like in the drivers seat when the driver opened the throttle on 8-liters of V8!!!

[on2wheels52]

I was a fan of those orange McLarens. Dragsters that cornered.
Jim

[Jim Bremner]

I have a 8.1 litre big block chevy!


too bad it's in my 10,000 pound motorhome