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512 cid C series on Dakota chassis- build thread


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55 minutes ago, wayfarer said:

I dunno....are you sure they will hold up...? ??

Ha! I put one right under the middle of the step between the bed & cab and it felt rock solid climbing in and out of the bed area. The one by the door I might need to send outriggers fore and aft so it doesn’t act like a fulcrum when people step in the wrong place but it’s pretty solid too. The fronts catch less of the frame but all 4 hang down. 

 

I thought I was done for the day but my kid went to play with the neighbor’s kid for a couple hours and I managed to get all 4 brackets in. The boards just sit right on top. I figure I’ll let the fender locate the rear and do a sheetmetal screw down into the front where you can’t see it. As long as they don’t rattle the brackets can just take the weight. Maybe they should be spot welded after the bed is totally located and mounted? I hate rattles. 

 

The mounting structure underneath is toast. I cut it away where it wouldn’t let the boards sit directly on the bracket.

 

She’s a stepside again! The best kind of truck!  Next the front bumper then the bed. The engine block should be done any day now too I get to start checking bearing clearances, filing piston rings, shaving the oil pickup boss to clear the stroker, measuring compression height- lotsa fun not to mention mocking up the driveline to mount it and start making a firewall.

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Edited by Radarsonwheels
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On 8/10/2018 at 12:44 PM, RNR1957NYer said:

Sweet stance!!!

Thanks! It’s been a long road but it’s finally coming together. Fingers crossed that it isn’t too low with the hardwood bed, big block, and trans installed. At least I have an aluminum top end but I’m sure it will still settle an inch or 2. Always three steps forward two steps back!

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Wow I’m really impressed with this 440 source stroker kit. The mains are all in spec, and the crank endplay checks out good too.

 

I mocked up a rod and piston on all four corners to see how much I need the deck shaved to get zero deck for good quench and compression ratio. I got lucky with this block- both decks are nice and flat.

 

The driver’s side deck is square with the pistons .003” in the hole. The passenger side is slightly out of square with #2  piston .003” down and #8 .007” down. With a felpro 1009 gasket (.039” compressed thickness) that puts me right in the .043-.047” quench distance- for a street motor I’ll take it! 

 

The one rod measured .0015 clearance on the big end which is good for me. If the other 7 are in spec I will be good to screw this thing together without any more trips to the machine shop costing more money and time.

 

I’m getting excited!

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Edited by Radarsonwheels
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Rod bearings are all good with .0015”-.00175” clearance. The wrist pin bushings fit perfect. The books all say the #1 rod will hit the oil pickup boss even with the smaller journal chevy big block style rods and ARP 12pt cap screws used in the 512 kit. I got all psyched up to drape my block for carbide burr surgery and do an extra round of cleaning but when I mocked it up there is a mile of clearance. No whittling!

 

Looks like I can start file fitting my piston rings, installing freeze plugs, pipe plugs and oil fittings, and build this sucker up. 

 

I can’t wait to hear it!

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More motor progress!

 

I tried saving $ by using a band clamp piston ring compressor but ended up chipping a ring on my second one and had to order a spare set for a single cylinder. I went ahead and ordered a tapered 4.375” ring compressor while I was throwing good money after bad and it was $40 well spent. The spare rings cost $20 so not the worst setback. 

 

Ten minutes to file fit the new ring and all the pistons slid home nicely. The 440 source/scat rods all fit with nice side to side clearance and I was glad I had ordered their custom main bearings that have the crank fillet side relieved on the lathe. No knife work was necessary for the aftermarket crank fillets. 

 

The theme this week is $20 setbacks. I boogered the rear cam bearing installing it but it is the smallest one and can be installed through the rest when my replacement set comes in. I figured why not install the others and see if the cam spins or binds? That way if I have a problem the replacement bearings are already en route. The other bearings drove in uneventfully with good alignment to the oiling holes. Even better news was that when I stabbed the cam in (without the rear bearing) it spins well and does not bind. I have read that the mopar big blocks often need the cam bearings reamed out. I know how to slot an old cam to make a ream but I wasn’t looking foreword to doing that. 

 

When my $20 worth of new cam bearings comes in hopefully the rear one also spins freely and I can move on to degreeing the cam and finishing up the shortblock. 

 

The old chassis complete with fresh kingpins, all new shocks, new shackles and bushings,  t5 transmission, rebuilt 230 with repop fenton headers and weber carb,  mopar 8.25” rear, and even some fresh tires went back to it’s former owner today.

 

He has a late 30s dodge pickup cab and title so he’s going to make some kind of jalopy or something cool out of it. Maybe even get some of those swoopy fenders to match his cab. He is a former pro fabricator and welder so it’s in good hands. 

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The motor should be done by next week. I’m taking my time screwing it together. The cam is now degreed and in at 105°icl, heads are torqued, intermediate shaft bushing, freeze plugs, and pipe fittings all installed. I’m mocking up the intake and deciding what gasket combo to use so the ports and bolt holes line up.

 

I have to decide what color to paint it soon. Any votes? My usual is hemi orange block with natural aluminum top end and stainless bolts but the ‘stealth’ heads look a lot like stock iron heads if you paint them. I never did a motor where you paint the whole thing bolts and all after assembly. I’m not wild about chrome or billet but I do like clean and tidy.

 

Anybody that participates in this forum would know in about one blink of an eye that there is zero stock about my truck but I wouldn’t mind if it looked similar to a stock truck engine bay with some bolt ons and not a fancy built motor hotrod engine bay.

 

I always liked boring and stroking motors and letting people scratch their heads when they were way faster than they should be- “yeah it’s just a 383 with a cam in it” haha

 

Anybody know what colors you would see on an early poly 318 motor? I wouldn’t mind doing the whole motor turquoise or something.

 

I would love to see pics of y’alls engine bays if you dig your color scheme. Thanks!

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7 hours ago, Radarsonwheels said:

I always liked boring and stroking motors and letting people scratch their heads when they were way faster than they should be- “yeah it’s just a 383 with a cam in it” haha

 

 

LOL! Years ago I helped a friend build an Olds 350 for his '80 Cutless. It was a sweet running engine and really packed a punch. Someone finally caught up with him at a stop one day and asked what he had under the hood, because he couldn't keep up with him. "Just a 260 with a cam." was his reply. ?

 

If you want a "sleeper" engine, why not just use the Mopar big block blue?

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Well I sat looking at the motor a while, with the M/T valve covers and edelbrock intake it already didn’t look very stock, and I was about to start fitting the milodon deep rear sump pan which is decidedly not stock. And I have some ratty new old stock headers to paint

 

My sleeper fantasy is kind of laughable.

 

I decided I liked the way the freshly cleaned block looked how it was so I painted the exposed iron and steel with high temp primer and flat cast aluminum color. It’s a little brighter than the iron but far from silver or chrome. 

 

Hopefully tomorrow I will have time to  bolt down the intake. I decided to just use the steel valley pan/embossed intake gasket with a small amount of sealer since the bolt holes seem like they are lined up nicely for port match.

 

 

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The motor is pretty much done! I’m mocking up the accessories now. The late ‘70s square back alternator is a beast so I think I’m going to probably run the alternator off the 89 dakota. It’s one of the mini size denso units. In theory it should be easy to make brackets for it- we’ll see. 

 

I still have to make bed mounts and locate the bumpers before I stab the motor in. I’m thinking I’ll mark the frame where the firewall and radiator sit, then pull the body and drop the late big block spool mounts onto the 89 dakota v6 spool mount brackets.

 

Then I’ll see if my crank offset side to side will work with my pinion location and how much space I have between the water pump pulley and the radiator. I assume the trans crossmember will need a complete re-work too. The firewall will probably need a huge hole cut in it and I anticipate needing a full driveshaft tunnel under the seat too. I just got another load of 1” .120” wall square stock to build up the bed & cab floor frames.

 

It might be smart to finish the bed mounts and bumpers then set the body aside until the chassis is fully built and plumbed with the driveline installed, then go back and fit the body back over the deiveline.

 

I’ve come so far and I might be something like 1/2 way to driving this crazy thing. 

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I got some fancy two+ year old (out of spec for nhra) five point harnesses coming from a guy the moparts site. I’m thinking I can mostly use them for lap belts unless I want to strap in tight so I can’t reach the glove box for some serious fun. 

 

I also scored a clean used exhaust system for crazy cheap. It’s 3.5” mandrel bent tube with 3.5” flowmaster 40s. I’m hoping for a nice slightly lopey hollow burble at idle and a loudish wide open throttle. Pictures don’t do it justice it’s cartoonishly big but beggers can’t be choosers and at this point my budget is getting slim! I think with 512 cid I won’t miss a little torque off idle if the exhaust is a little too big!

 

 

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Today’s fun: alternator upgrade and bracket fabrication.

 

The 1989 dakota had a slightly crusty but very desirable nippon dendo 90 amp mini 12 volt alternator. A lot of people use them not just for weight savings but also for their good output at low rpm which might end up being important since I’m running an electric fan and shroud off a chevy  hhr. They are supposed to be super powerful and long lasting fans and pennies on the dollar compared to fancy aftermarket fans. Plus the shroud fits my aluminum  radiator perfectly.

 

My 400 donor motor had a huge ‘square back’ late 70s mopar alternator with a huge bracket that tied into a huge AC  compressor that is not going back on so I decided to fabricate a bracket using the fancy threaded tensioner  that I cut off of the dakota alt bracket. 

 

It’s not the most flowing beautiful piece of automotive artwork I’ve ever made but the adjustment bolt hole on the alt is 180° from the mounting hole so it had to go up around the corner to properly angle the adjustment slot. It does clear the header and valve cover in the back and has a nice amount of adjustment. 

 

The 400 motor’s power steering bracket looks like it holds the same pump that is still hanging off my power rack and pinion  on my ‘89 dakota chassis so that will get re-used and has one belt running the water pump and PS pump. 

 

So the hard part of mocking up and fabricating the accessories is pretty much done. I just have to mount the PS pump s brackets on the block so it’ll be ready to go when it’s in the chassis.

 

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I agree! Especially with a hemi you want that motor to be the star of the engine bay.  I went back and looked at my brackets again. Unless I’m willing to pivot the alternator from a different location than the bolt hole in the head there just isn’t a tighter or more practical spot than up high on the passenger side. The travel is limited by the fuel pump and the header bolt, with more adjustment available overcenter than under. 

 

I will not sacrifice strength safety or reliability for laziness or speed but I will take a little uglyness here and there, at least for now, for the sake of practicality. 90 amps sure sounds like it’ll do the trick and free is a great price for the alternator and home made bracket. 

 

If there is room in the chassis after the motor is mounted I’ll take another stab at prettying up a low passenger side bracket.

 

Maybe some ‘speed holes’ drilled in the upper arm would fancy it up in the meantime? After google imaging 440 brackets and seeing all the huge ugly spiky billet chromed serpentine belt bracket setups I kind of like mine a little better. 

 

I’m also telling myself that the gull wing hood access will take focus off the front view of the motor compared to a traditional muscle car. Soon I’ll see what it will actually look like...

 

 

 

 

 

 

 

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Got moving again a little bit today. I measured and dropped off a driveshaft to get shortened and balanced with new U joints, my cheapo stainless shorty block hugger headers came in 4 days ahead of the tracking # and they look like they’re gonna work, and I started making a frame for the bed floor.

 

The bed floor frame was the hardest thing to figure out. The sides (tailgate & front too) are just sitting cribbed up to the correct location and every time I pull the bed off it is woobly and wonky- makes me nervous. I decided to use angle iron kind of like the stock flanges but a little higher then I made a rectangle frame with 1” .120 wall that will eventually hold the plate steel body (bed) mount brackets. 

 

 

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