4.0 OHV refresh/upgrade questions

[MarcFromNH]

Keep the updates coming. I've got a spare 4.0 for my '96 that's a good candidate for some upgrades.

Did the shop have to do any welding to repair the sunken seats?

 

[truckerdawg]

I will offer a different opinion. The 410 cam is a noticeable replacement over stock. When you get the right pushrods, and rockers there is no noise from the valvetrain unless your stock springs start to float above 5000 rpm. I would suggest new springs. This is a v6 and it will never pull at 800 rpms like a v8 would- this is not for you. The header needs checked for flatness to mate to the head-definitely-you cannot pull it with bolts and it does need to be as perfect a match as you can get so you do not have problems with blown exhaust gaskets. I have that header in ceramic and it cost me $50 to have it shaved.-still way better than the price of JBA. There is one better rocker than the others. I will have to search that. Get the luk progold clutch

 

[Macneil87]

I'm going to follow this thread from now on. I like the sound of what you are doing. I've got a 4L that is getting up in mileage and I wouldn't mind sourcing a good used one to do a rebuild on and swap it in once complete. I am curious to see how that cam performs for you.

Nice work on the porting. Every time I pull heads at work (I am a mechanic; and work on a fleet of fords..), I am tempted to port them but have never had the time.

 

[Uncle Gump]

Porting heads is a tricky business... an art form really. I've never had a flow bench so I typically sent out all the serious port work to someone that did.

What I did do regularly without a flow bench was match port the gaskets to both the intake and cylinder head ports... not so much on the header flange but a little to taper out the transition.

It appears from your pictures that you could improve the gasket match a bit. It would smooth out the flow between the mating surfaces.

 

[GoMopar440]

Did the shop have to do any welding to repair the sunken seats?

No welding, I believe they just replaced the exhaust seats with new ones.

This project kinda stalled out since the weather started turning wintry around here in Montana. I definitely don't plan on trying to pull the engine and trans while there's still snow on the ground. Building a garage (40' x 30') so I can work inside and out of the weather is on top of my priorities list for next year.