any ways to tell if engine is street ported ?
 

I have a 93 Rx7 .

Ok so here's the deal . I bought a JDM motor I was told it was rrebuilt and had good compression .

I tested it 105 PSI both rotors , 3 even 60 psi pulses . on each rotor , engine's been in the car for a year now .

it idles fine , it runs fine . I'm on stock twins .

But my vacume is at 18 at idle , I thought this was ok . but I read that 18vacume is on the low side on stock ports .

So I'm wondering for 105 PSI , is -18 vacume at 850 RPM"s on the low side of normal or maybe the off chance that the engine may have a street port and thats whats causing the vacume to be a bit lower .

also at 80mph the vacume is at -10

so maybe I'm just grasping at straws hoping I dont have to start looking fora spare keg to start building LOL

18 inches sounds fine for a stock port engine.

Get ahold of a bore scope with a camera and a light on it. Remove the uim and stick it down the lim. If you know what to look for you can tell.

105 compression and 18" of vacum @850rpm is just fine.

Wait I re-read it. If your getting 60 per face how do you come up with 105? Remove the valve when you compression test.