[mosesburb]

Originally Posted by dfairchild19

im stuffing a 6bt/4500/205 in my 71 and came across a question (and im sure there will be more) about your choice of radiator and shroud. i saw that you use a tall radiator and matching big block shroud from a 73-87. what was your reason for going this route and not using an aluminum replacement and bb shroud for a 67-72? i am thinking about using one of the aluminum replacements from ebay but i am not sure if my fan would fit into a 67-72 bb shroud as it is from a 94 6bt. i believe that you said something about the non intercooled fans being smaller in diameter than the intercooled fans.

I had just bought that radiator and shroud for a truck that generously donated its organs to the Sub. When I put the big block in this, that was the radiator and shroud that I had available, so after I was told that I couldn't put that radiator and shroud in this truck, I decided that was the radiator it was getting.

Go back and re-read the fan mount part of the story. You are going to have to deal with your fan mount being the same as my original one. It offsets the fan to the driver side and also drops it down a bit. I think that is going to prevent you from using a GM shroud in your conversion. You may be able to swap it out (very expensive) or make your own shroud. It has been so long that I don't recall fan diameters, but I do believe your fan will be too large for the opening in a big block shroud. You might want to post up a question in the general truck forum about the ID of a BBC shroud then determine if yours will work. Keep in mind that you want a minimum of one inch aroud the fan for clearance. I had that spacer made to run the big lblock chevy fan, but I have since swapped the big block fan out for a small block fan and that is more than enough to keep this thing cool in summer with front and rear a/c cranked while idling in traffic.

As far as replacement aluminum radiators go, just make sure you get one with two, one inch rows of tubes. None of that three row or four row crap that is so abundant on ebay. The width of the tube is what makes an aluminum radiator transfer heat better than a copper/brass unit. Copper/brass is a better conductor of heat, but the tubes can not be made as wide as an aluminum tube, so that is why copper/brass radiators get three and four rows of (typically) half inch tubes. Aluminum can be made larger giving more tube to fin contact area, thus the tube can more efficiently transfer heat from itself to the fin and ultimately the air.

Originally Posted by dfairchild19

Also, do you have any advice when fitting the drivetrain for its final location? ive got the entire drivetrain sitting between the framerails right now. i am going to put some important items in place(coresupport, radiator, hydroboost, steering box) before making mounts and crossmembers to make sure i dont have any interferences.

This is a tricky one as there is a definite "place" the motor needs to end up. I set mine as low as I possibly could while still maintaining *reasonable* clearance to the front diff. If I had it to do again, I think I would still do it the same way. Setting the motor higher has some benefits. For one, it would make your fan mount fit a little better. It would give you more clearance to the front diff. One thing it would do on the negative side is you would lose motor to hood clearance. It doesn't seem like it should matter, but once you start trying to fit stuff in, you will realize it. Around this time is when I figured out why almost everybody put a body lift on their trucks when they did their conversion and used a six inch suspension lift. This is an option for you as well. It would have made my life easier as well, but I have a buddy of mine that would not let me do it and in reality, I didn't want it myself. A one inch body lift would have made a big difference for me.