I am posting this for my husband (in a way) so I dont know the exact words and such. But I will give you what I know.

We have a 1990 F250 4x4 with a 5spd. It had a 351W efi in it and we took that out and put a rebuilt 351W (top to bottom) with a carb on it in the truck. It has a new water pump andstarter. We took off the smog crap (dont get on me about that either) and stuff. It sounds awesome and runs fine at an idle. But our issue is that it is getting HOT. I am trying to help find answers to this without steppin on his toes. The T-stat is a 195*, like I said new water pump (dont ask what kind cause I dont know), we did use the surp belt instead of the V belts and all the pullys are turning fine, has a flex fan on it, holly 650 carb. I want to know why it is getting hot, like into the 220 range. He says that it is new and tight and needs to be drove (broke in) to make it get better. I have read lots of things about this, T-stat, water pump (fins...how can they be bad on a new pump), timing (where does it need to be set at?). If ya got any ideas let me know. But this is a 351w that I believe is 30 over and has never been fired till now. Help me out guys cause I need my truck!

Thanks so much!

 

I think the water pumps are different between the two types of belts. The serp belt turns in reverse of the v type belt. Try putting the old one on, off the motor you took out

 

That water pump wont work with this block. They years are way different. We were going to but had to go get one that would match up to bolt holes cause the 1990 had a different hole pattern then the old 351 we put in there

 

if you want to keep the serp setup you have to run a reverse rotation pump. if a reverse rotation pump doesnt fit then you need to pull the timing cover off and put the 90 5.8 timing cover on it so you can put the correct pump on. I am willing to bet this is your primary issue.
also was the Tstat installed correctly, i have seen many times where they are installed backwards so check that also.

on a side note, why didnt you guys keep the efi? all of that hardware could have swapped right over.

 

I do know that the front is all set up to work with the serp belt. So if a pump has a serp belt pully then it is a reverse pump?! And the t stat was done right. And as far as keepin the efi... well the old school has less things to figure out if anything were to go wrong and you dont have to mess with the computers and stuff and all the eletrical that is with them. The old school has just a few main wires and thats it. You dont have to carry around the shop in the back of the truck just incase something happens. Just a few tools and you could fix it along side the road. He wanted to go carb!

 

if the motor is running to lean then it could also cause it to be running hot. but it is possible it just needs to be broken in fully also.

what is the timing set at? and how do the plugs look? its possible there is an airbubble in the system also. ive seen where this can cause a motor to run hot.

also now that your running a carbed setup you dont need a 195* stat in there. you can run a 180 and be fine. the 195 is specific to the efi.

and i just want to make clear are you running a water pump for a 90 5.8 or a water pump for the year of the actual motor you installed? sorry the statements above are a little confusing to follow.

 

Ok so can you tell me, when your standing infront of the pickup, what is the rotation of the serp belt pump to go, and the v belt? I am thinking that this may just be our problem. I do think that the pump we found to fit the older engine was for a v belt. And if what you say is true then I think we got it! See we kept all the pullys off the 90 engine and put them on this engine.

 

yes that is in fact your issue. bummer is you will need to pull the timing cover off of the 90 block and install it on the engine you just installed. This will allow you to run the proper water pump.

if you havent already go buy a new water pump for a 90 5.8. they are not expensive and will save you from having to replace a pump to soon.

 

I dont know what the timing is at. He hasnt said. But it starts with no problems and idles and runs just fine. THere is no spitting or sputtering. I do know when he was messing with the timing that when he moved it a bit she would have issues. So he put it back and it was fine. He once thought that it was a tooth off and when he tried that she wouldnt do anything. So he put it back and again nothing wrong there. So Im sure that it is pretty darn close if not right on. Our first set of plugs were fouled cause it was running ro rich. We bought the regulator for the fuel so we could take the pressure down from the efi pressure to carb pressure. THat is all done and if he goes up or down with that also you can tell a big differance there too. Cause it is either starving or getting to much. And the air in the system he has tinkered around with that and we arent getting any out. That was our first thought was air in there. So now back to this pump.

 

Standard rotation = Clockwise viewed from the front of the motor
Reverse rotation = Counter clockwise viewed from the front of the motor

 

So is there no way to use what we have?

 

right on, you guys are close for sure. i think a carb needs about 6-8psi.

 

do you still have the 90 5.8 available? if you do then just pull the water pump and use it. you already need the timing cover anyway

 

yeah it is right in there. The efi was way to much for the carb. We went to summit and bought the regulator that they said was what we needed. Just need to figure out this other deal now. Thanks for helpin me out here.

 

The thing is that we used the water pump for our core for this one so I need to get a new one then and a timing cover too?