Can a 90 12 valve vacuum pump be swaped out with a newer style? 92 to 2002 with out major work?

 

yes, but not as good of a pump.

 

What he said.

What year truck are you putting it in? Does it have a vaccum booster or hydraulic booster? If it has a hydraulic booster all you need vaccum for is the heater/ac vents and the CAD if you have a 94 to 02 truck.

 

I have a 74 swap with the 1st gen non intercooler with a 95RH behind with 241D trasfer case. I keep getting oil leaks from the vacuum pump area seems like I reseal it and with in month or two it starts to leak. Or i'm doing something wrong on sealing it? it flustrating having oil leaking from the front end and spreading down the frame. Any good sugestions?

 

Do you have all 4 bolts and the angle brace that connects it to the bracket that braces the back of the injection pump? I have yet to try to reseal one, but I had one leaking and it was only held by 2 bolts and had no angle brace, I've heard that you should have everything bolted up tight or it will leak. I removed it completely and replaced it with just a pump off of a 4BTA that was in a bread van and I need to get an electric vaccum pump to run my vents. I have hydroboost brakes on mine.

Are you positive its just the vaccum pump thats leaking? I've seen the back gasket for the front cover right behind the injection pump break or crack and leak oil down the block.

 

I have just standard breake boster, when I have taken it off before it looks like just the vacuume and power steering area is wet with oil, non on the block under injector pump, it is all stock yet the motor only has maybe 40,000 mile on it. maybe its coming form the timing housing gasket were vacuum pump hooks up?