Vintage Mustang Forums banner

1 - 5 of 5 Posts

·
Registered
Joined
·
31 Posts
Discussion Starter #1
I am converting my stock 66 manifolds to hipo manifolds. I went to the muffler shop and they want from 160.00 to 190.00 just to swap the two and that doesn't include anything beyond the manifold. Before I do it myself I wanted to know if it is really that hard that the $ is justified or is it easy enough to do it myself and anything I should know..tips, tricks, etc.
 

·
Registered
Joined
·
9,104 Posts
Changing manifolds is usually not hard. You just have to make sure you align and seal them properly. If they are old and rusted, removal might be somewhat difficult. Use PB Blaster to loosen the rusted bolts. If you force the bolts, they might snap.
 

·
Registered
Joined
·
2,061 Posts
It's easy to do it yourself. Just make sure to get the longer manifold to head bolts (hipo manifold has thicker flanges). There's a lot of argument on whether you need a gasket between the manifold and heads--if both surfaces are perfectly straight and smooth, you don't really need them. The factory didn't use them, but they started out with true, smooth surfaces. :) I used gaskets on mine (aluminum heads, hipo manifolds). and cut the ports on the gasket to match the manifold and head ports. I also reamed out the manifold ports a bit to get extra flow. :biggrin:

You will need to get a new H-pipe, or have the exhaust guys make one for you as your stock one is too high and won't fit. If you want, put the manifolds on in the parking lot, then have the exhaust guys fab the H-pipe (or buy a pre-fit one from NPD or equivalent). The bolts on the manifold closest to the shock tower might have to be put in the manifold before you put the manifold on as there isn't much room to start them, otherwise.
Daniel
 

·
Premium Member
Joined
·
7,081 Posts
Ensure you have a 6 pt socket, not a 12 pt. The Snap-on style, with the "lumps" in the center of each side, to grip the flats of the bolt head, rather than the corners, works better.

Your H pipe will have to be replaced, so you may just want to cut it off at the manifolds, rather than trying to unbolt the manifolds from the pipe.

A small arnsenal of extentions, U joints, etc, works well, and even an open/box wrench (I use a tappet wrench, as they are skinney).

Last, you may consider loosening the motor mounts, and raising the engine up a couple inches. Opens up some of the hard to get to bolts.
 

·
Registered
Joined
·
8,661 Posts
I'm converting my 351w stock manifolds to long tube headers and am in the same boat. Mine is probably ten times harder, due to the increased width of the motor. I called around the local shops for a price for them to cut my head pipes and connect them to my headers. Around $100 for them to do it was the cheapest and i was installing my own headers (which is a PIA may i add). So most of the cost is absorbed in them cutting the H pipe and making the necessary bends to hook them up to the manifolds. Removing the manifolds on your car can usually take 15-30 minutes, depending on how well the bolts are stuck.
 
1 - 5 of 5 Posts
Top