V6 Willys Wagon Conversion


Gear Grinder
Oct 6, 2010
Willys Model
Willys Year:
I plan on installing a GM 4.3L V6 into my 57' wagon. I am trying to gather as much info as possible. Anyone out there with experience in this conversion? I would appreciate any and all help that I can get. I intend on using the stock T90/Dana18 combo. I have the adapters needed but I am not sure about exhaust. Can I use stock GM manifolds? Are there other considerations? Thanks in advance for any responses.
I would use the stock manifolds if it were me. Headers are a pain to me, to much under hood heat and possibility of blow out of the gaskets at the most inopportune times if not installed correctly. Just wondering, is your wagon 2 or 4 wheel drive. I had a man come by my house today checking if I happen to have a f- head to put in a wagon. He also said he may go with a GM v-6.
Is your wagon a 4 cyl. or a 6 now? Just wondering if you will have to change your trans input shaft, one more thing to consider. If you go with headers you probably have options such as short or long tube or maybe fenderwell if thats your thing. You could also get ceramic coated headers to cut down on heat. I agree header gaskets are a pain but there is some new technology there such as the ball sockets on the collector side. You should also look at motor mounts maybe from novak or advanced adapters if you did not want to fab your own. Then you get into your fuel delivery carb or injected. Oh I forgot, the cost. If you have manifolds with your engine it's one less thing to buy.
welcome to the forums. I would use the stock manifolds for less heat underhood.
First, thanks for all the replys. This wagon had already been modified to some degree. One of the previous owners decided to install a 2.2L 4cyl. out of a Ford, fabricating his own mounts and altering the firewall.
I have a donor wagon (1961 I think) that I will scavange parts to repair the firewall. I already have the 4.3 and trans set-up. I wanted to keep the stock exhaust if possible. I have converted this engine to normally aspirated (i.e. carburated) fuel system with HEI ignition. I plan on purchasing engine mounts from Novak. Disc front brakes in the future.
This is a 4x4 wagon which I hope will at least maintain the character of the original.
Welcome to the forum. I would stay with the stock manifolds. I had to with my Ford V-8 due to the original clutch and brake pedals being used and the master cylinder still on the frame rail.

I also agree with the under the hood heat of headers..... They put out a lot of excess heat. Even with wrap on em.

Eric B
I like your plan of action...some modifications but keeping it looking stock...your choice is good and asking questions, measuring twice are the beginning to an accomplishment for the long haul. There are plenty of projects/post here on the forum of your up coming swap. Good Luck and happy motoring!
I also like and appreciate a Pure Stock Willys....
You might experience a firewall clearance problem with the gearboxes on the original location and original firewall. You told that your firewall was already modified, may be that will just be of help when installing the new engine. Personally I would have considered the TH 350 or 700 automatic behind the engine. This will move the engine somewhat forward while the transfercase will still be located as before (with prop shafts as before). With the automatic you are still able to run a Warn (Saturn) overdrive, which is a desired option with the original 5.38 geared axles. The TH700 will also help a lot with the overdrive forth gear.

The engine should be moved a little towards the driver's side to clear the front pumkin and make space for the front propshaft when using an automatic transmission.
All this talk about location can be easily fixed, however you do open yourself up for some work. IMO, the way to do it right, the body has to come off... this makes location of motor mounts, boxing frame, modifying the firewall, transmission mounts easier to work on. Removing the body might discourage you, but it shouldn't....what 14 bolts and five other guys to help lift?