1979 620 build in Utah

[Utahskier]

Just now, Utahskier said:

Thank-you!  I’ve been lurking in here forever it is nice to be a part of the community finally

 

33 minutes ago, ]2eDeYe said:

Wow, nice work so far. Welcome aboard ?

 

[paradime]

Looks like your Grandfather knew what he was doing when he left his truck to you. Awesome job so far man. When you're done shredding the slopes, it's back to work.

[Utahskier]

7 minutes ago, paradime said:

Looks like your Grandfather knew what he was doing when he left his truck to you. Awesome job so far man. When you're done shredding the slopes, it's back to work.

Ya he knew how to take care of stuff, but the truck still needs like EVERYTHING done to it lol

[Utahskier]

[Utahskier]

Got opera windows reinstalled with new gaskets from vintage rubber.  Check our the overspray I still haven’t cleaned off the door window hehehe

Edited December 31, 2018 by Utahskier
Misspell

[Seeker > 620 KC]

Did you remove the windshield when you painted?

 

[Utahskier]

Just now, Seeker > 620 KC said:

Did you remove the windshield when you painted?

 

Yes it was cracked and I plan on getting a new one.  I have the gasket already, got a whole kit from thailand on ebay.

[Utahskier]

If anyone knows the best places to source a windshield it would be much appreciated...

[Seeker > 620 KC]

Is the ft windshield seal plain or accept the stainless trim? I also have a 79 with orig glass, but pitted and light scratches. Don’t want to replace it till I have to. 

[Utahskier]

New seal is plain, the old seal is complete junk but I was able to save the trim

[Utahskier]

Same as the opera window plain seal no chrome trim

[Seeker > 620 KC]

Hopefully someday , dream, hope, wish, someone will reproduce those seals that accept the trim. Are you putting the AC back in?

[Utahskier]

32 minutes ago, Seeker > 620 KC said:

Hopefully someday , dream, hope, wish, someone will reproduce those seals that accept the trim. Are you putting the AC back in?

Yes it gets really hot here.  It needs new system though as the factory air is toast and it’s hard and expensive to find the Freon it takes.  Do you have any recommendations?

[Utahskier]

Ya I looked and looked for window gaskets that would take the trim.  Felt lucky to find any gaskets at all.  I hope the Thailand stuff from eBay will last on the rear glass, windshield, doors etc.  The opera window gaskets were pretty expensive for what they are but they seemed higher quality 

[Seeker > 620 KC]

https://ratsun.net/topic/74127-620-ac-compressor-mount/

 

[Utahskier]

27 minutes ago, Seeker > 620 KC said:

https://ratsun.net/topic/74127-620-ac-compressor-mount/

 

Wow! fantastic link and your write-up was extremely informative.  Thank-you!  This will prove to be invaluable knowledge when I get the AC going!

[Seeker > 620 KC]

Glad to help. Stay cool

[Draker]

You can buy real r12 on ebay. Not too hard to get, but yeah upgrading the system makes sense.

[Utahskier]

9 hours ago, Draker said:

You can buy real r12 on ebay. Not too hard to get, but yeah upgrading the system makes sense.

Ya I don’t want to throw old AC on a newly rebuilt motor.  Looking for better cooling, horsepower and gas mileage.

[datzenmike]

Generally, increasing horsepower and mileage, is mutually exclusive. Where do you drive most.... highway or around town?

 

Highway

Of all the 620s the '79 used a low 4.11 differential, all other years were 4.375 or higher. This was to lower RPMs to improve mileage but at the expense of acceleration. If you drive primarily on the highway a '79 5 speed will lower 5th gear engine RPMs by almost 12%. You won't get 12% better mileage but it will be slightly better. The '79 4 or 5 speeds use the same lower gears so acceleration will be the same in town. Additionally you could find a 3.90 differential from a later 720. This will drop acceleration in town but further improve highway mileage.

 

Town

Find a 4.375 differential from an earlier 620 to improve acceleration. Gas mileage in town won't change much because you can always drive around in a higher gear now. Mileage on the highway won't be as good as the 4.11

 

 

[Utahskier]

2 hours ago, datzenmike said:

Generally, increasing horsepower and mileage, is mutually exclusive. Where do you drive most.... highway or around town?

 

Highway

Of all the 620s the '79 used a low 4.11 differential, all other years were 4.375 or higher. This was to lower RPMs to improve mileage but at the expense of acceleration. If you drive primarily on the highway a '79 5 speed will lower 5th gear engine RPMs by almost 12%. You won't get 12% better mileage but it will be slightly better. The '79 4 or 5 speeds use the same lower gears so acceleration will be the same in town. Additionally you could find a 3.90 differential from a later 720. This will drop acceleration in town but further improve highway mileage.

 

Town

Find a 4.375 differential from an earlier 620 to improve acceleration. Gas mileage in town won't change much because you can always drive around in a higher gear now. Mileage on the highway won't be as good as the 4.11

 

 

Ya I was just thinking a new AC would rob less horsepower by virtue of less weight and make it more efficient because it’s easier to turn....I’ll be doing mostly highway miles with the truck.  I really appreciate the help, just incredible to have advice from gurus like Datzenmike, Draker, and Seeker.  I’ve been reading your stuff for two years in anticipation of doing this 620.  

[Draker]

There is a guy local to me that built an ac system for his 620 using an ebay under dash unit. Then he had custom hoses made at a rubber shop. He used a compressor from a v8 of some sort, but mentioned it robs a bit too much HP. I'd probably look at adapting a compressor from a small modern motor. You'll need to make your own bracket of course. I want to say the reason he went with a v8 compressor was because of the hose fittings. Otherwise if you pull from a scrap yard, you'll need to pull the hoses to go with the compressor.

Edited January 2, 2019 by Draker

[Utahskier]

Went to my local machine shop today and checked the progress.  The cylinders did need to be bored the crank only needs to be polished.  Needs new exhaust valves in the head.  Needs New oversized pistons here is a pic of beautiful reconditioned block:)

Edited January 3, 2019 by Utahskier

[Utahskier]

[Utahskier]

Broke mounting screw on rear taillight assembly when removing taillights for paint.  Drilled out old one and installed a machine screw in its place.  The parabolic reflector in the light is almost like thick tin foil and can be carefully moved/bent out of the way.