I'd like to see a picture of those BHP headers and if you are putting Twin 45DCOE's on a 140, the intake HAS to be a copy of Volvo's as it is the correct length & flows the best AND should clear any exhaust header.

no text.

How big is your cam?

The stock 3-2-1 cast iron exhaust manifold works just fine up until you need 4-1 style headers.

Up until you go bigger than 240° @ .050" & 110°LSA, you want headers that work a little bit everywhere since you have built a motor that should take full throttle from idle in top gear.

Cheers,
Paul.

There are several different intake manifolds out there, and each comes with its own clearance issues. Maybe it would be easier to use a different intake than look for a different header.

The ipd header won't improve performance, regardless.

Which intake are you working with?

Cameron
Portland

the stock injection manifold was listed in the rsport catalog for stage 3 and 4 engine upgrades. they do say to extend each down pipe 4 inches before merging into 1 pipe. there was a long branch header also but finding 1 now is impossible.

Can this be overcome by some grinding of the exhaust flanges? They may look fine but finding a set which works better than the cast iron one is difficult. That one works fine up to about 150bhp so the engine has to be in a high state of tune for that. Twin Webers don't automatically guarantee a massive boost in power. Again, they do look good though.