I installed the FMS crate engine (M-6007-XE3M) and it sounds great but i have a problem. It reacts fine and starts up okay but i cant sit at a stoplight....it just dies. It feels like a have NO vaccum. And because of the lack of vaccum, my brakes feel VERY stiff. Ive been through ALOT of mechanics and most of them say" I cant understand it". We all checked the vac. lines, leaks, etc etc. I'll give u a list of the extra stuff i added to the crate engine:
Trickflow intake and spacer, Trickflow 70mm t/b, bbk headers, bbk cai, bbk fuel reg, bbk, o/r exhaust, 93' cobra 70mm MAF, 24lbs inj, MSD distributor w/ crane cams ignition box and coil, and SCT custom chip for the mods.

And one thing that may be a factor is FMS said "when dropping this engine into a 79-93 foxbody make sure u use this conversion kit". It has a timing pointer, crankshaft damper, reverse rotation water pump, oil pan and thats about it. I never bought this kit. Maybe that will fix my problem, but i dont think that will have anything to do with VACCUM. So with these mods, i cant understand whats up!!!. If anyone can help it will be GREATLY appreciated. Any ideas???

 

if the brake pedal is really stiff then you definately dont have any vacuum, or unadequate vacuum. put a guage on it. should be around 17-20 at idle. how does it idle, with a leak big enough to affect the brake booster it should be a huge leak, you should be able to find it with some starting fluid. just put a vacuum gauge on it, or have someone do it for you, that will be the problem.

 

if your cam is that radical then you will need a vaccum canister. its a can that holds vaccum for the brakes/motor

 

so its definately a vaccum problem right?....will a vaccum advance help any?