My exhaust manifold has a crack in it and I was looking to replace it. Looking at something that was somewhat future proof for moving to a 225 super six setup in the future. Any suggestions?

I purchased a new Dorman exhaust manifold online for my 170. The quality is good and I have been running it for about 4 months now without any problems. The price was a bit more than I wanted to spend, but I also don't have any of the problems associated with using a preowned manifold (already warped, wont seal properly, hidden cracks, non functional heat riser valve, etc).

On my 170 engine it seems the counter weight wheel for the exhaust manifold heat valve hits the oil dipstick when trying to remove it from the dipstick tube. I have come to the conclusion that the new Dorman casting is geared more toward use with the 225 because that point on the exhaust would be a couple of inches higher up. So this will work for the 170 and the 225 if you upgrade.

I still say go new, and with a search you will see that Slantsixdan recommended the new Dorman as well. Thats why I went that route in the first place. Or you could find a nice set of Dutra duals!

Thanks! Dan messaged me about the dorman as well. I'll need to convert the choke because its a '64 /6 right?

I do believe you have to modify the choke. I went with the electric choke kit (again recommend by Slantsixdan). Search electric choke consversion. Simple hookup and once set and tuned works really well. To be honest it was pretty well ready to go when it went on. I tapped a wire that runs to the ballast resistor so it only has power when the key is in the in position. I think the kit is number 1231.
Doug

How challenging is it going to be to remove this manifold? I feel like those bolts are not going to be excited about coming out after so long.

I left my intake and exhaust bolted together until the whole unit was out and on the ground. The studs that stick out of the head are a bugger if any break off. I put a large set of vise grips on the stud close to the head and try to wiggle it back and forth until it breaks free and can be removed. Each of the studs is threaded into the water jacket of the head so be sure use blue locktite thread sealer. I think 542 or 242. Can’t remember right off the top of my head. The studs are Dorman number 675-093 they are double end studs and come in boxes of 10.
The intake to exhaust should have 2 bolts and one stud. The bolts are 5/16-18 and the stud is 3/8-16. Heat them up well and hit them with PB blaster or Kroil and try to break them loose without breaking them. Really the bolts and stud are more a part of the exhaust manifold, so if you get the new Dorman kit it will come with the stud and you will need two bolts. They will be 5/16-18 x 4” or 4 1/4”. Get the good gaskets (Remflex) and DO NOT overtighten them. It is 10 ft lbs or less if I remember. The bolts on the head get tightened before you tighten the intake and exhaust down to each other. .
So it will be heavy and not the most fun in the world, but really it isn’t a huge or terrible job. Also before I’m done ranting here, make sure you have all the butterfly washers and the two brass washers you will need to hold the intake and exhaust back on the head. All butterflies with the exception of the top middle of the intake and the top outermost exhaust manifold studs. The middle intake is a round washer and the outermost exhaust studs get the bras washers with a special locknut. These manifolds were designed to “dance and flex” on the head during their expansion and contraction so as to prevent cracking. The brass washers allow the exhaust manifold to expand and contract appropriately.

Awesome! thanks for the information. I looked up all the parts and the only thing I can't seem to find is the butterfly washers. Can you point me in the right direction for getting those?

The butterfly washers will come with the Dorman kit. Sometimes you can find them on eBay by searching Slant 6 (slant six, etc) They are the triangle shaped washers that hold an intake tab with one side and an exhaust tab with the other side. If you lay them on a flat surface you will notice that they are convex shaped with the highest point where the head stud would go through the hole in them. Put the intake and exhaust together loosely with the 2 bolts and 1 stud. Place the gasket on the head studs. Place the unit (intake and exhaust together) on the studs sticking out of the head and then begin to place the butterfly washers on before the nuts. The washers will go on the studs with the convex side out toward the drivers side and they generally point down like an arrow if on the top studs, and up like and arrow if on the bottom studs. The flatter side will be touching the manifolds and the nut will be touching the highest point on the washers. I can not for the life of me figure out how to post pics or receive notifications on here, or I would have gotten back to you sooner and posted pics so you could see what I am talking about.

Good luck,

Doug