Ok Just recently bought a 1990 FC N/A has 1200 on rebuild... Supposedly it has been Half Bridged... I would like to know if in fact it is.. But I don't know enough about them to tell... my idle is quite erratic.. When you first start the car its very erratic up and down the brap brap. But after its warmed up its semi normal, but this is after i changed the O2 it was shorted and runing very righ and adjusted the tps best I could... suggestions or if any of you guys could direct me in the right direction...

 

You can't tell unless you open it up, or at least shine a light into the intake ports.

 

hmmm... Maybe i'll buy this boroscope my Snap-On dealer has been trying to sell me.

 

How much vacuum does it pull? Post a video or sound clip.

Any bridgeported car will not have a semi normal idle. It will be a very distinctive "rap rap rap....rap rap rap....rap rap rap....".

 

Getting my baby back from the Transmission shop... Full rebuild and new exedy clutch... I will test the vacuum aaron... I wish I had a camera with good sound myabe I have my freind help me out with that so you can hear it... It sounds like its cammed deeply... and its a shaky beast till you raise the RPM too

 

as was said, the idle should give it away. however if worse comes to worst, then you could use your finger in one of the secondary intake runners to check.

 

ok got it back from the tranny shop... its smooth... need shifter bushings tho... Aaron got a vacuum test for ya... used old vac/turbo guage for test... about 5 in hG at idle, when i revved it some it gave me a higher reading!! that can't be right but i dont know... 10 and 15 inches

 

That vacuum kind of does sound like a bridgeport.

But, it could also be caused by many things: vacuum leaks, misfiring, dead injector, way too much fuel, etc.