michaelmarter

Looking at the 3.9lt multi point & 4.0lt multi point there is a power difference of 9Kw.......???? Is this from the different cam timing. The 3.9lt cam has timing overlap between intake & exhaust values of 28 degrees, while the 4.0 has an overlap of 30 and the XR6 cam 32....Obviously this helps to create a scavenging affect that sucks more fuel mixture into the pots....

question....considering the value springs, cam journals are the same for the 3.9 & 4.0, has anyone put a 4.0lt cam into a 3.9 - if so did you notice an improvement or is it a waste of time????

mick

Troutman

If you are after power, an aftermarket cam will be far less compromised than a 3.9, 4.0i or even XR6 item.

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Jack Travis, E-Series Acting President

1989 Ford Fairmont Ghia turbo/GL replica (underway)
1994 Eunos 800M
1990 Ford Laser S

rextus

3.9 and 4.0L cams are different, with the 3.9 having slightly more
lift (0.240 vs 0.236). I think the 4.0L might have gotten an intake manifold with slightly larger diameter runners but they look the same to me so maybe this is incorrect. Has anyone had any experience with Crow's '825 cam?

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Progress is like a Commodore, if you don't keep pushing it, it stops.