1973 Monaco gets a small 450 stroker.

[heyoldguy]

Found ourselves building a 450 stroker for our 1973 Dodge Charger.......but switched gears and decided to pull the Monaco out of the weeds.

Currently it has a 400 2bbl. We'll remove that and put it in the corner, take another 400 out of the bone pile and start the stroker.....It's still a work in progress but here are some highlights so far......

Find an old 440 forged crankshaft and turn the counter weights down .120" in radius to clear the 400 block and then send it to the machine shop to have the mains cut to 400 size.....

Save the stock rods and have them reconditioned with ARP bolts and replace the stock pistons with KB251 quench dome pistons............

The 346 heads we are starting with will need a little work..........

And some new 2.20/1.84 stainless steel valves

The block has been square decked, bored and honed for the new pistons...........

A light mill of .010" to clean the heads up, new bronze guides, ported and the combustion chamber flats all machined to .110" deep.

 

[Moparwilks]

good stuff!

 

[saforwardlook]

73 Monacos are one of my favorite automobiles - great choice.

I would like to see this one when done, hopefully the body will get refreshed as well.

Best wishes.

 

[Alchemi]

Nice one mate, You mentioned cutting the crank .120, where did that put you diameter wise and do you know how much clearance do you actually have to the block? 7.250 gets mentioned a lot but im interested to see where that gets you clearance wise

Asking as I have to do the same and are looking to keep as much outer diameter as possible so I can under cut the bobs to balance - mines getting offset ground to 3.9, a new unit would be nice, but I have the crank and getting a nice crank sent to OZ is -very- expensive

I have a bit of work to do on a lot of other things before I get to my crank, but its good to think on things before doing them

 

[heyoldguy]

Nice one mate, You mentioned cutting the crank .120, where did that put you diameter wise and do you know how much clearance do you actually have to the block? 7.250 gets mentioned a lot but im interested to see where that gets you clearance wise

Asking as I have to do the same and are looking to keep as much outer diameter as possible so I can under cut the bobs to balance - mines getting offset ground to 3.9, a new unit would be nice, but I have the crank and getting a nice crank sent to OZ is -very- expensive

I have a bit of work to do on a lot of other things before I get to my crank, but its good to think on things before doing them

When I checked this time I found .050" clearance to the block in these areas in cylinders 4 & 8. With a previous build the crankshaft still hit there even after cutting the counterweights exactly the same amount and I had to grind the block for clearance.

 

[twostick]

That's a lot of work for 10 cubes.

Kevin

 

[Mike66Chryslers]

When I checked this time I found .050" clearance to the block in these areas in cylinders 4 & 8. With a previous build the crankshaft still hit there even after cutting the counterweights exactly the same amount and I had to grind the block for clearance.
View attachment 445052 View attachment 445053

I was going to mention this too. For my 451 stroker build, the counterweight edges were chamfered for clearance, not modifying the block. And I'm pretty sure the counterweights on my crank didn't have to be turned down for clearance except for the chamfering along one edge.

 

[heyoldguy]

After Performance Machine in Idaho Falls, Idaho decked the block and ground the crankshaft for me I checked crankshaft run out and the dial indicator never moved off zero.

I checked all deck heights with one rod and one piston and found everything to be within .001" i.e. .015"-.016"

 

[heyoldguy]

That's a lot of work for 10 cubes.

Kevin

You ain't seen nothing yet................

 

[heyoldguy]

We're hidden away in this mountain valley 2-1/2 hours from the automotive machine shop in Idaho Falls so we need to do as much as we're able. As the quench dome on the KB251 pistons is .260" tall they will smash into the cylinder head unless they are milled down some.

Never having done this before we needed to make some things to get going...like a soft base to set the pistons skirts on.

Then we needed some way to hold the pistons securely to the 6061 aluminum square bar while cutting the dome so we used a 3/4" cold rolled round steel bar to slide through the piston pin..........

And used that to clamp the piston to the mill bench. We carefully tightened each clamp enough to hold the piston during the milling process yet not so tight to deform the piston skirt. Using the dial indicator we had to tighten each lamp from side to side so that the piston crown was parallel to the bench. The indicator is behind the dome on the piston crown......

We measured each rod for it's length and cut each quench dome so that they were .110" above the deck surface. With the head depth at .110" also, the quench would be whatever gasket thickness we use. In this case it's the FelPro 8519PT1 so we'll have .039"..............

Somehow this picture ended up out of sequence and I'm not smart enough to sort it back out.

 

[heyoldguy]

We're going to use a solid flat tappet camshaft in the build so we needed to come up with an adjustable rocker arm setup. Being economical when possible we went to the shelf to see what was available and came up with these three sets. The top is a very early set from the late 1950's or early 1960's. Middle is a set of 440 Source Rockers and the bottom is a set of Crane Gold Race rocker arms from 10-12 years ago.

Figure we'll use the Crane rockers. But as the Crane's have such poor rocker arm geometry on the 346 heads we must make a relocation kit to move the rocker shaft up and away from the valve tip.

 

[Mike66Chryslers]

Those ones at the top... Are they like regular stamped rockers with the pushrod cup drilled and tapped for the adjuster? Are they thicker than regular stamped rockers in that area?

Why did you decide to not use the (Chinesium?) 440 Source rockers?

 

[twostick]

Those ones at the top... Are they like regular stamped rockers with the pushrod cup drilled and tapped for the adjuster? Are they thicker than regular stamped rockers in that area?

Why did you decide to not use the (Chinesium?) 440 Source rockers?

Those top ones look home made. The only factory adjustable rockers I've ever seen were ductile iron.

Kevin

 

[twostick]

Mike Beachel at B3 Racing Engines is the guy to get your valvetrain geometry sorted out.

He sells custom spacer kits that will move the shaft up and away the correct amount specific to your combo based on measurements from your engine.

Good guy to talk to and he has excellent tech on his website.

B3 Racing Engines LLC - Performance Engine Building and Mopar Valvetrains

Kevin

 

[heyoldguy]

Mike Beachel at B3 Racing Engines is the guy to get your valvetrain geometry sorted out.

He sells custom spacer kits that will move the shaft up and away the correct amount specific to your combo based on measurements from your engine.

Good guy to talk to and he has excellent tech on his website.

B3 Racing Engines LLC - Performance Engine Building and Mopar Valvetrains

Kevin

Yep, and even though we make our own correction kit in-house.......we do not make them for or sell them to the general public. For anyone with roller rocker arms I would encourage them to contact B3RE.

With our self-made kit we changed the pattern from an off-center .110" wide sweep to that shown in the 3rd photo.....

This is what the sweep pattern looks like for a .625" lift cam with this kit. It is about .035" wide.

 

[heyoldguy]

Those ones at the top... Are they like regular stamped rockers with the pushrod cup drilled and tapped for the adjuster? Are they thicker than regular stamped rockers in that area?

The earliest ones I have seen, other than these in my possession, were in a picture of a dragster running a 413 in the late 1950's. It is rumored that a few sets were made for factory supported race teams from back then. My father was on a team that ran stock bodied sedans for land speed record attempts at the Bonneville salt flats during the 1950's and 1960's. I believe he acquired them around that time. I'm pretty sure he used them on his 1959 Plymouth at Bonneville in 1959.

Those top ones look home made. The only factory adjustable rockers I've ever seen were ductile iron.

Kevin

They are stamped steel rockers that had a threaded bushing (probably shaped like a mushroom lifter) pressed up through the bottom of a hole drilled the rocker arm. There is no welding on the rocker.

I'm trying to remember if some of the early wedge powered Chrysler 300's had solid flat tappet cams and adjustable rockers. And if so, what did those rockers look like?

 

[carrman]

That's a lot of work for 10 cubes.

Kevin

When you have a good cook, this recipe works very well. I loved my 451, but hack machine work did it in.

 

[twostick]

If all you want is 452 cubes a .060" over 440 gets you there with a lot less dicking around.

If you want to build a 400 block to hurl a C body around in a sporting manner, you add 108 cubes to it with a 4.25" stroke crank. By the time you subtract the machine shop bill to modify the 440 crank from the $750 that a new crank costs, it becomes the cheapest torque and horsepower you will ever buy.

Can 452 cubes make some steam? Of course but with some serious tradeoffs for driving 4500 lbs of Monaco around. If you are planning to approach 500 HP, 512 cubes can do it falling out of a tree with a combo your Grandmother could drive.

Kevin

 

[heyoldguy]

If all you want is 452 cubes a .060" over 440 gets you there with a lot less dicking around.

If you want to build a 400 block to hurl a C body around in a sporting manner, you add 108 cubes to it with a 4.25" stroke crank. By the time you subtract the machine shop bill to modify the 440 crank from the $750 that a new crank costs, it becomes the cheapest torque and horsepower you will ever buy.

Can 452 cubes make some steam? Of course but with some serious tradeoffs for driving 4500 lbs of Monaco around. If you are planning to approach 500 HP, 512 cubes can do it falling out of a tree with a combo your Grandmother could drive.

Kevin

Ouch! You make some good points.......however........

I think I will continue to have my fun, uh, dick around a little more.

As we have purposely made the hold down clamps too wide, we now cut them down one at a time to center them over the valve tip on the other axis. Here they are off center...........

And after taking them to the vertical mill we are now centered over the tip. But we need a spacer between them.......

I keep a selection of wide steel spacers .125"-.700" and hundreds of hard steel shim spacer in .015"-.060". In years past the best quality shims I purchased were from Hughes Engines. We used a .015" steel shim between the hold downs and the rockers and then turned down, on the lathe, a .660" or .700" spacer until we had .015"-020" total clearance between the pair of rockers.

Then each pair of rockers, shims and spacers is bagged and marked as to which cylinder head (#1) and cylinder (#1) it was prepared for. The hold downs are etched for each pedestal, then the lower pedestal spacers, bolts and studs are bagged along with the hold down clamps together for the corresponding cylinder head.

So now...........
Come on, let me have my fun. This poor little 450 surely won't make as much power as our normally aspirated, single 4-bbl, 91 octane, solid roller cammed, Edelbrock RPM headed, 451 stroker that made 787 HP, but it is what I want to build this time.

And a lot of these parts are laying around the shop so's I don't have to buy things like cranks and such.

 

[MEV]

Ouch! You make some good points.......however........

I think I will continue to have my fun, uh, dick around a little more.

As we have purposely made the hold down clamps too wide, we now cut them down one at a time to center them over the valve tip on the other axis. here they are off center...........
View attachment 446184

And after taking them to the vertical mill we are now centered over the tip. But we need a spacer between them.......View attachment 446185

I keep a selection of wide steel spacers .125"-.700" and hundreds of hard steel shim spacer in .015"-.060". In years past the best quality shims I purchased were from Hughes Engines. We used a .015" steel shim between the hold downs and the rockers and then turned down, on the lathe, a .660" or .700" spacer until we had .015"-020" total clearance between the pair of rockers. View attachment 446186

Then each pair of rockers, shims and spacers is bagged and marked as to which cylinder head (#1) and cylinder (#1) it was prepared for. The hold downs are etched for each pedestal, then the lower pedestal spacers, bolts and studs are bagged along with the hold down clamps together for the corresponding cylinder head.View attachment 446187

So now...........
Come on, let me have my fun. This poor little 450 surely won't make as much power as our normally aspirated, single 4-bbl, 91 octane, solid roller cammed, Edelbrock RPM headed, 451 stroker that made 787 HP, but it is what I want to build this time.

And a lot of these parts are laying around the shop so's I don't have to buy things like cranks and such.

DANG!!!, You have GOT to post that dyno sheet!!