445 mud motor build

[KMcCullah]

Just wrapped up mud racing last weekend. I did 5 different races this year and took 2nd place 4 times! I'm sick and tired of that for sure. Especially when its stroked small block chebbies that are doing all the winning!!
The 390 I've been racing has been a reliable overachiever and will be tamed down a bit and used in a 77 highboy.
So I'm getting started on a 445 for my 72 F250. This is the truck my dad bought in 1978 or so.
The heads are C4AE 6090G castings.
Each head had several broken bolts in the upper exhaust flanges. After sacrificing many 7/16 nuts and a 3/8 tap, I was able to get the flanges in working order. Two studs had to be drilled out. The tap was cut short and threaded in from the back side of the flanges after drilling since good threads were there.


Edit- still trying to post nice pics without doing the attachment deal.
Editx2- Figured out the photobucket website.

[jayb]

Getting those frozen bolts out of the top exhaust holes is a miserable job, for sure.  Looks like you've got it handled.  Are you going to do any porting work on the heads?  What size valves are you looking at?  Get those heads in shape, because the 445 will need a lot more air than the 390...

[KMcCullah]

Yes sir! These heads will be the big consumer of my manhours for this build. I just picked up a Milwaukee die grinder with a big variety of burs and cartridge rolls. The grinder is just a on or off deal so I'm in the process of putting a dimmer switch and outlet together to get a variable speed grinder.
Valves will be CJ size. 2.09in 1.65ex.
I've been talking to several local hotrod guys, asking about flow machines. So I've got a few leads now.

[DEANs427]

I worked on my brothers 428 mudder a few years back, you need to put the hardest exhaust seats you can find in those heads or it WILL pound them out in short order.

[Heo]

Getting those frozen bolts out of the top exhaust holes is a miserable job, for sure.  Looks like you've got it handled.  Are you going to do any porting work on the heads?  What size valves are you looking at?  Get those heads in shape, because the 445 will need a lot more air than the 390...

I fix the frozen bolts this way.I drill in the center with a 1/4 inch drill
all the way through then i take a big washer with a hole big enough
for the bolt and tigweld the washer to the bolt then weld a nut to the
washer let it cool for a couple of minutes the just unscrew it
the weld makes the bolt to shrink and with the 1/4 inch hole in the
bolt it shrinks more

[My427stang]

Are you planning on headers?

If so, I think its tough to find a set of headers with the early port design.  That's why I stayed with my D2s.  I actually tried Hedman truck headers on a friend's Edelbrock heads (same exhaust port as yours) and I couldn't have made the ports match exactly, and close enough too some pretty serious slotting of the holes to the point I didn't know if I could get a wrench on it if I did it

[KMcCullah]

I'm running a set of fenderwell headers now with C1AE 6090A heads. But like you said, they don't line up very well. I did slot the flanges a bit but things are still not quite right.
I keep seeing FE header flanges on epay, so I think I will build a new set of fendewell headers. Speedway motors has bent tube kits that look easy. Heck, anybody can build headers! lol

[My427stang]

Sounds like a good plan to me!

[KMcCullah]

This is the D4TE block that I picked up for the build. It had two thrown rods,#3 and #7. Kinda strange I thought. The only obvious damage I see is a chip on the bottom of the #7 cylinder.


The bores are standard 4.050. So before I invest time and $$$ in this thing, I hope you guys will chime in with some priceless wisdom.

[jmlay]

I am not sure haw far you plan to bore it but there are some fairly decent dings in the cylender wall. I hope they are not too deep where boring woud not remove them or you have to go excessivly over size.

[KMcCullah]

Yea the dings worry me too. My thumb nail guage tells me the dings are .010 to .015 deep. I'm hoping the thing will clean up at 4.070. I would rather have thick cylinder walls than a few extra cubes. I need to set up a bore mic and measure the ding depths.
Roughing out the damaged bores to see where or if they will finish up before ordering the stroker kit may be wise also.

[KMcCullah]

After a bunch of life happenings, I'm back. The scope of the project will have to downsize, so for now I will have to settle for heads, intake and headers. I can squeeze another year out of the 390 short block.
A few months ago I removed some broken bolts from the upper exhaust flanges. A few of the holes we're really ugly. Bolts rattled in the remaining threads. 2 of the holes had been drilled by the previous owner(s) and tapped 1/4" off center. The remaining pieces of broken bolts were left in and tapped. What a mess! So I made some threaded sleeves with 9/16-12 threads on the O.D. and tapped 3/8-16. The off center holes were plunged thru with a end mill and tapped 9/16-12. Now the holes are back on center!

I dimpled the threads with a center punch for an interference fit and installed the sleeves with a bolt and a jam nut, leaving a 1/16 or so standing proud for milling.

I milled .020 off of the exhaust flanges and still had some ate up spots.

It would have taken .060 to make that flange pretty. Will use some high temp pooky on that one.
So the rest of the required parts are on the way. Got a smokin' deal on a set of Manley 427 exhaust valves on epay. I did some wishful messing out in the garage today. Tried the full size exhaust valves with a std bore 390 block.  1.75 no go! Going to have to be around CJ size. Maybe see what 1.66 looks like. On the intake side will see how 2.15 fits.

[jayb]

Nice work on those heads! Looks like a solid repair, and definitely worth it to save an otherwise problem set.  FYI I've cut the exhaust flange on heads .060" before with no issues, but I'm sure you can seal them up as is with some high temp RTV.

[machoneman]

Wow, that is nice work indeed. I'd not worry about the entire perimeter of each flange as the one shown has more than enough flat area to seal well.....JMO.

[drdano]

I dig the DIY Keen-serts. Did you tap a bolt shank with threads or actually cut the outer threads yourself?  Should be a long lasting fix.