74 Challenger with twins

[YellowThumper]

Going to make an attempt to detail my loooong build using this as motivation to keep plugging along.
I have owned this since 83.
Original 318 3 spd floor shift. Power nothing. It did not even have a front sway bar.
Early on I converted to 4 spd with pistol grip and added 340 X heads to the 318, front and rear factory bars, P/S, P/B, bulge hood, fender louvers.
Since then: 318 and X heads are gone. It is now all La360 similar date code. At the time I still had to have it smog checked in California and was having issues getting it to pass the visual. Even with the emissions acceptable car could not pass with a 4 barrel because it came factory with as 2 barrel.
Off with what I wanted and on to 360. This I would swap from 2 for emission testing and then convert back to 4 every other year. Thankfully that is now all over with here.
As I have noted probably too many times end goal is going to be 5.9 Magnum, twin turbos and Megasquirt EFI.
I am not going for the gold with horsepower. End of day I will be aiming for a touch over 500 hp at motor.
All street nothing intended for more than that.
Moldmaker for plastic injection tooling by trade (35 years) so building stuff is in my blood.

Note: All I will be posting is from a few years ago bringing it up to current.
Starting with the car.
Paint is a 20 footer. Most of it remains original.
A (re)change early was to convert power brakes to hydroboost.

Mike

[Cuda Cody]

    

[nsmall]

Way to keep your car after all these years and wonderful CA emissions.  Keep us posted and keep on it.  I found reading other people's build threads to be motivational to the point of distracting me from doing what I should be doing on my car.

Keep the updates coming.

[YellowThumper]

Next...
I made my own custom widened Ralyes.
Actually started them about 20 years ago. then kicked them aside in a pile.
Finished them for spite a couple years ago.

Oldsmobile 15" hoops I split in half around the diameters. Keeping as much of the width as I could from inner and outer halves.
Welded inner and outer halves together. Had some cheap old tires mounted with no centers to pressure test for leaks. Had a few initially. just let all air out and added some spot heat to weld to get it flowing. It took a couple tries but got them sealed. then welded in the centers. This took some creative hammering and clamping. All done at home. Brought my indicator gauge home and borrowed a hardened and flat ground (and round) plate from work to measure from. to set back space correct and also make sure it was running true.
Rears are 8-1/2" wide with 4-3/4 BS. Running 275/60-15"
Fronts remain standard hoop at 7" wide.


Mike

[RUNCHARGER]

Cool: I have some Oldsmobile wheels at work I think I am going to snag to repop some 450's.

[YellowThumper]

Update for one of the fun items I have made for it.
Gotta advertise the plan to reality.

Designed in Solidworks updated hood emblems that mimic lettering size and style of originals.
Machined with Mastercam.
Cut the top side of lettering out of some plate.
Lettering has vertical sides down at bottom of them that I will eventually be able to clamp in vice for finishing cuts on back.
Lettering on plate shown did not yet have the fine detail machining finished yet.
Held plate upside down in vice.
Machined the 2ea mounting posts using a boring head with cutter mounted in reverse. Started large and kept adjusting it until I reached the diameter posts I was looking for.
Then machined the remainder of backing plate off a little at a time. Took as much off as I thought I could get away with comfortably.
Saw cut the plate into pieces separating the emblems. Clamped them in vice individually and finished machining the backs down to height.

Machined in plate at work but all the removal to finished pieces were done at home with manual equipment.

Mike.

[Chryco Psycho]

The emblems turned out great 

[Cuda Cody]

   Those are impressive!   

[YellowThumper]

The emblems turned out great 

  Those are impressive!   

Thanks and thanks. They were tough as the place I worked at the time did not have high speed spindle capability. Small cutters took forever to pencil them in.

[YellowThumper]

On to the engine.
Current in car engine is LA360.  I changed the intake and all the front accessories to 5.9 Magnum version.
Reason for this is I want what I want but will not cut the car up anywhere to accomplish this. All changes to car are mechanical. Overall I have had to only drill a few small mounting screw holes. Nothing major.
Magnum accessories are very compact to motor in comparison to the original setup. Water pump is also approximately 2.5 inches shorter.
Compact accessories provided the room for turbos.
Shorter water pump allowed me to relocate radiator off core support closer to engine. This then provided a pass thru for intercooler piping. Of course pics will be provided...

This is what it took to mount a Magnum manifold on LA engine.
General size is correct but the new mounting bolts are vertical instead of angle matching head face.
They basically exit the manifold in same location. Just different angle.
Was not able to redrill on my mill so i had to break out the redneck ingenuity...
Drilled a thick block to the right diameter and also a slight angle that matched the old.
welded the block to a plate I could clamp to manifold.
Used a gasket to scribe for correct locations.
Clamped the block on and drilled by hand. Drill, remove and re-clamp, drill and repeat.
All the new holes came partially thru the vertical screw hole posts. For this i made some 1/2" thick washers that I milled out a partial round for clearance.
All this work to adapt to the LA is only temporary to get to my final end. I already have a Magnum motor that will eventually make it in.
Step by step partials so I can continue to drive and enjoy it.

[RUNCHARGER]

That was the fun way to do it. Drive it as you make changes. It keeps from getting too bogged down in too much work with no seat time.

[YellowThumper]

That was the fun way to do it. Drive it as you make changes. It keeps from getting too bogged down in too much work with no seat time.

Went full tilt on a M-stang years ago. 20 years later I was able to drive it again. Vowed never to let that happen again.

[YellowThumper]

The factory position of Magnum P/S pump mounts high and was in the way so it had to move.
Made a bracket setup to move it lower  It is approximately in the same location as original.
This was actually the 3rd go around. I kept trying to piece a bracket together using parts of the factory items so I would only have to make half the items.
In the end I chucked all the piecemeal parts and made a complete new one.

Mike.

[Chryco Psycho]

Nice work !

[YellowThumper]

Looking at my last pic I saw the 36-1 crank trigger wheel.
Made a round out of square old school with a lot of hand cranking.
Machined the wheel and added slots for infinite adjustments. Welded some tabs to the pulley and turned them on lathe to true them up for mounting. Worked out exactly as I wanted on the Magnum mule. Except the La360 has its large external counter weights and it would not clear them. Cut out the center in disgust and welded it on to the pulley instead.
My mantra. Jump in with both feet, occasionally fail and then find another way. Gotta keep moving forward.

Mike.