251 swap

[ggdad1951]

From a dynamics and statics point of view I can see how a higher point in front might alleviate some issues, but then again these engines don't really buck around so it might not be as much of an issue?

[Desotodav]

1 hour ago, Merle Coggins said:

... I remember seeing something about the "Floating Power" front mounts that showed the advantage of having the front up higher, under the water pump. I can't find the information now, but I remember it had something to do with the oscillations and/or vibrations..

Merle

Merle, I recall seeing that in a post of an old training video clip. They showed the comparison between Ford and MOPAR highlighting the fact that the higher front engine mount and lower bell housing mounts provided diagonal mounting points for better engine stability.

All of the trucks which I have owned here in Oz have been fitted with 25 inch engines. I know that it might seem a little radical... but could a fella (with a smaller engine) think of drilling out the rivets and cutting the welds to slide the whole front cross member forward to cater for the larger engine? One would have to mess around a little to re-line the radiator u-frame mount. I'd be happy to provide measurements as I am yet to put the 53 truck body back on the chassis...

[Dave72dt]

I found on mine that the frame tapers in  as you go forward, meaning it's narrower at the front crossmember than it is where the transmission would bolt in.  The taper starts at the front of the rear leaf spring hangers and goes forward.  Moving it forward may not affect it much but might affect bumper mounting and if I recall, doesn't the radiator support bolt into that crossmember as well.  All the front sheet metal is hung off that support as well.

Edited December 30, 2016 by Dave72dt

[NiftyFifty]

Your correct Dave....going too far forward does get into that area, the front mount is riveted directly to the front crossmember.  I think raising the engine  is possible, but only about an inch room to work with...best scenario is to cut and build a gap into the crossmember like shown in the thread.

[Bill from SE WA]

Hi Everyone,

Spent the day in the shop getting the old motor out.  Cylinders 3 and 4 were seized in the 230.  It was a mess.  I was pleasantly surprised to see the bolt pattern on the fluid drive matches the crankshaft on the 251 that I am going to put in.  I'm just learning about these engines, and didn't expect they would be the same.  Took me a bit to catch up on all the comments here.  I did modify the lower crank pulley on the front of the motor from the 230 to fit the 251. It is the same width V-groove just a smaller diameter.  The pulley on the 251 had timing marks on the flange so I need to figure out what I am going to do to put timing marks on my smaller pulley. 

Based on everything I have seen, my plan is to try and just raise the 251 up a bit at the front to miss the front cross member.  I think that will work and won't have that much impact I hope.  Here are a few pictures.  You can see a paper template I made and cut out and slipped on the fluid drive studs to check the bolt pattern.  I am crossing my fingers that these will bolt together.  I also included a picture of my new motor.  It came out of a M37 brush fire truck.  In Eastern Oregon and Washington rural fire departments used these trucks to fight brush fires.  The truck it came out of was really low mileage and the engine runs well.  I've got it up on a stand where I can work on it and get it detailed before it goes in.

Trying to decide what I want to do for the intake and exhaust.  The factory dodge dual intake/exhaust setup is really cool - I wouldn't mind using one of those if I can find one.  I see headers are easily available.  Does anyone make an aftermarket dual intake for a 25" motor?  I see 23" intakes but that's it. 

Thanks for all the comments. 

 

 

 

[B1B Keven]

Any progress?

[Bill from SE WA]

I decided I needed to get a few other things in order before getting the motor put in place.  I have already determined it will fit with no problems. I am not notching the front cross member for the front pulley. I will just raise it slightly to miss. 

I have been following the various threads on lowering these trucks and thought this would be a good time to do this as well.  However, I wanted to do the axle drop a little differently.  They make a new dropped axle for an F1 Ford.  This axle is only slightly narrower than the Dodge front axle and you get the benefit of everything being new from hub-to-hub.  It's a cross steer setup just like the Dodge and you can purchase dropped steering arms that will clear the spring.  The parts are easily available and when it's all said and done, I think it probably costs about the same as some of the other set ups people are doing.  The only thing I did was welded the F1 Bolt pattern on the spring perches and drilled new holes to mount the Dodge leaf springs.  The Ford frame is straight and the Dodge tapers.  

Here are a few pictures.  I put the axle in ahead of the stock axle.  You can see the shock mounts almost line up perfectly.  The second picture the spring pads are right where they need to be. The third picture shows the drop. The last picture shows the drilled out spring perches with on of the reversed springs.  I have also been collecting a few parts for the motor - Ellis dual intake with Zenith carburetors. I am just about ready to put the axle under the truck.  

[B1B Keven]

So, what I'm gathering is, to put a 25" motor in the hole a 23" came out of is to just raise the front a bit to clear the cross member?

Bell housing and clutch bolt up?

[Bill from SE WA]

I am keeping the fluid drive and it matches the crank everything else bolts up on the bell housing.  The radiator may need to be moved forward a little but that won't be too difficult.   I will add a couple holes to bolt the motor mount to the front cross member. 

[B1B Keven]

Like Reg did in this thread.

 

[Plymouthy Adams]

10 hours ago, B1B Keven said:

So, what I'm gathering is, to put a 25" motor in the hole a 23" came out of is to just raise the front a bit to clear the cross member?

Bell housing and clutch bolt up?

to just raise the front a tad will alter the entire phasing of your drive line and possibly cause some serious vibration issues and premature wearing of the u-joint...am not sure in a truck what will need be changed to make the bay larger...I cannot respond to this aspect of the change.

[Reg Evans]

2 minutes ago, Plymouthy Adams said:

to just raise the front a tad will alter the entire phasing of your drive line and possibly cause some serious vibration issues and premature wearing of the u-joint...am not sure in a truck what will need be changed to make the bay larger...I cannot respond to this aspect of the change.

That's what I thought too.

[Bill from SE WA]

Sorry forgot to mention I am using the smaller front pulley from the 230 - see earlier posts.  It already cleared the front cross member when it was on the 230.  When I say I plan on raising the front of the  motor I am not talking about much, just enough to slip the belt on or prevent oil pan interference.  

[Plymouthy Adams]

look close at  the pulley...many have cutouts 180 spaced to allow for slipping on and off belts already and if you have that style, then your main issue will be with length and the pan.  Some have taken their cars cross members and notched them for this difference without loss to integrity.  Again I am not familiar with a pic of the truck cross frame to visualize what may or may not work.

[Don Coatney]

4 minutes ago, Plymouthy Adams said:

look close at  the pulley...many have cutouts 180 spaced to allow for slipping on and off belts already and if you have that style, then your main issue will be with length and the pan.  Some have taken their cars cross members and notched them for this difference without loss to integrity.  Again I am not familiar with a pic of the truck cross frame to visualize what may or may not work.

From my experience the cutouts or flat spots are found on the harmonic balancer's not on the pulleys. Oil pan clearance issues are mostly related to tie rod clearance at least that is the case on cars. Not sure about trucks.

[Plymouthy Adams]

not all assemblies are harmonic balancer either..some are just hub spacer and pulley combinations...again, depends on model on hand...

[B1B Keven]

51 minutes ago, Bill from SE WA said:

Sorry forgot to mention I am using the smaller front pulley from the 230 - see earlier posts.  It already cleared the front cross member when it was on the 230.  When I say I plan on raising the front of the  motor I am not talking about much, just enough to slip the belt on or prevent oil pan interference.  

Sounds logical. How about motor mounts? Just add some steel like Reg?

 

[Bill from SE WA]

No, just planning on welding in a nut plate to screw a bolt into similar to what is there now.  I plan on using the 230 front floating power mount.