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Stuck between two 620's


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I picked this 1974 up a few weeks ago for $100.00 











After i got it home i took the seats out and the floors where in really bad shape. someone tried to fix them with fiberglass.










So i got on the net looking for floor-pans lol!!! (not much luck).  I did however find this on CL.














it also came with this 1976 620 and a boatload of parts for $400.00 . the floors are bad as well. 






















so now im not sure what one i want to fix up lol. they both do run and drive. 


i also picked this up this week saved it from the scrap yard for $150.00. i was thinking about putting the engine and transmission in one of the 620s. what are you guys thoughts on that?   





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How's your mechanical skills, fabrication, tools, a place to work on the truck? Also you can do a compression check on the motor before you transplant it.






My brother and I have a nice large shop I'm mo master mechanic or fabricator but have done a little bit of everything I'm sure I will have lots of questions lol

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Ka swap one while driving the other. Then swap. Drive the ka powered one while you remove the cab from the first one and fix the floor pans. Then swap that cab on to the ka powered truck. No driveability downtime and you end up with the best bits. Then do whatever you like with the remainder.


If one is ball joint front end and the other is kingpin, do all the good stuff to the balljoint truck. Otherwise just pick your favorite.


And Icehouse sells a wiring box to make the fuel injection wiring fairly simple.

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I take a different approach. Forget the compression check.


If it runs now then it's a good candidate for a swap. Use it all and get it in the new truck then run it. If you roll the dice and come up a winner, then happy accident. If it turns out to be a turd, well then you're only out the time to change it out.


It's a gamble, but so what. If you win, then you win big.

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Takes like 10 minutes to do a compression check.  Wouldn't it be a good feeling that the compression is good or if bad and may be the deciding factor which one to keep. To each his own.

True. Good idea to take the time now.


Doesn't make one bit of difference though. He's already got the truck so knowing that it has bad compression now could only potentially force him to get the motor fixed or source another one before the swap.

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If one is ball joint front end and the other is kingpin, do all the good stuff to the balljoint truck. Otherwise just pick your favorite.




All 3 are kingpin 620s.  Too bad the roof was cut off the one with good floors as swapping the whole cab would have been easier than cutting out the floors and welding back in.  The floors would fit the 74 slightly better since they're the same (the cut up one was a 73 or 74).   The '76 radiator support is (slightly)  better for a larger radiator for the KA swap, but that's about it.

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Hot and cold compression numbers are very close to the same, but you're right that numbers could be artificially low on an engine that hasn't run in years.  Is it really 4?  That kind of number gets forgotten over time so it could be 3 or 7 or ???  May work out to your advantage.  After heat cycling the engine a few times (to full operating temp) I'd do another compression test to see if there's any change and make plans based on those numbers.  Even if you get up to 125, know that its a high mileage engine.  150 would be solid.  

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That's one possibility. Swapping the 620 cab and bed over to the hardbody frame would give him 15 years less wear and tear, plus all the new front suspension and brakes.


The two downsides to doing a body swap are that now you've lost some of the originality of the vehicle and second,  technically it needs to go through DMV with all the new info. Here in CA, a frame swap will cause a pre smog vehicle to have to go through annual emissions testing. If you can make a solid case for repair using the newer frame, DMV has the power to let it slide.


Before doing a frame swap, a good plan is needed. Take good measurements of both vehicles before disassembly. Measure wheelbase, wheel centerline position inside the wheel opening, distance from back of cab to front of bed, distance/height of body mounts on frame, etc.

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