I have a 87 635 m30 engine and am putting it into my 74 bavaria e3, the brake booster and the manifold collide and I either need a smaller booster or manifold. any helpers out there??dannyclune@gmail.com

that's the reason why the 635 has not a vacuum operated brake booster but this hydraulic crap- not enough room. Maybe the intake manifold of the older (series 1) 635 gives enough room. But I'm not sure if it fits the head you have.

Might be time to convert to the hydra-boost system.

I think the vacuum booster from the 528e may be smaller but I can not say if it will give the clearance needed.

Requires a 2002tii brake booster to fit. I did the same thing with my E9.

i was told that the brake booster from the 320i will give clearance, i have ordered one and will post later

i was told that the brake booster from the 320i will give clearance, i have ordered one and will post later

Nope. Tried that first. It is shorter, but larger around, much like the stock CS booster. I don't know if they changed the design over the course of the E21, though, as mine came from a late E21.