1980 c10 383 help

[SLDPULR]

So I'm taking a break on my 69 short wide body off resto to play with the 1980 c10 short wide I picked up a month ago. The truck is in amazing condition but has the anemic 305. I have the 460hp 383 I built for my 69 sitting on the engine stand and plan on swapping it into my new 1980.

First question is will all of the accessorie drives from the 305 bolt up to the 350 block? The truck has factory ac and I don't won't to loose it.

Second question is are the engine mount locations in the same spot? I have the red prothane mounts that I was going to use in my 69 and I was hoping that they would work.

Third question is can someone confirm my gear ratio. From the research I have done I'm thinking 273 gears. I have the original window sticker and it just says standard ratio. (12 bolt)

Last question is could someone chime in with torque converter stall speed recommendations. It's a single cab short bed, 460hp 383 with rpm air gap and 750 Holley dp. The truck is a auto th350. I would like to keep the 273 gears if possible just for highway cruising. All the research I did only pulls up converter stall speeds for camaros with 273s

Thank you

Pics of the truck for fun





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[Jaysonb]

I've had 2 1980 trucks, one had 3.08, and one had 3.42. With that kind of hp you should change all your fluids, and give everything a good once over, then you will see what gears you have. The torque converter depends on what cam you have, your cam card should tell you what you need to know. Everything from the 305 will bolt up, and your red mounts should work fine.

[Marshy]

My understanding was all the 305/350 accessories were interchangeable. You might want to confirm what your rear gears actually are. Heres a quick and easy way. https://www.youtube.com/watch?v=kGkwb76tkDw

Sounds like you might have 3.73 gears, they never made a 2.73 ratio. A 14 bolt with 10.5" ring gear came with 3.21, 3.42, 3.73, 4.10, 4.56, 4.88, 5.13, and 5.38 ratios.

[barry1982]

Hi There..... yes they did make a 2:73 ratio 12 bolt..... I have a 81' 4 x 4 with factory 12 bolt 2:73. Works great.

[Marshy]

Originally Posted by barry1982

Hi There..... yes they did make a 2:73 ratio 12 bolt..... I have a 81' 4 x 4 with factory 12 bolt 2:73. Works great.

What size ring gear? You sure its a 14 bolt? They did make a 2.73 ratio for the 10 bolt with 8.5 and 8.625" ring gears but I have not found any documentation of the 2.73 ratio in a 14 bolt. Doesn't mean they didn't though. Got any proof? I'm not an axle wizard so I'm all for learning something new.

Edit: Looks like that ratio was offered in '81 in the semifloat 14 bolts.
http://brochures.slosh.com/1981/pickups20.jpg

[Jaysonb]

The guy has a 12 bolt, not a 14 bolt.

[SLDPULR]

I will have to pull the diff cover to confirm the gears.

Here is my cam card. Hopefully someone can chime in with this info added to the thread.

[Jaysonb]

The rpm range for that cam is 2800 to 7000. I would use a 2500 rpm stall.

[SLDPULR]

^^^^i was thinking 2600-2800

[Jaysonb]

I'm sure a 2800 would be ideal, it seems that 2500 stall converters are pretty common, and cheap. I dont think that I would be able to tell the 300 rpm difference.

[Marshy]

Originally Posted by SLDPULR

I will have to pull the diff cover to confirm the gears.

Here is my cam card. Hopefully someone can chime in with this info added to the thread.

You might want to review Comp's web site. The description for that cam says; For '58-'98 262-400 cid Small Block Engines w/ Flat Tappet Cam - Pro Street/Bracket • Needs Good Intake, Headers, Gear & 3300+ Stall
RPM Range is 2800-7000
http://www.compcams.com/Company/CC/c...x?csid=89&sb=2

Here is the dyno sheet for that cam.
http://www.compcams.com/Technical/Dy...94H-10_001.asp

Originally Posted by Jaysonb

The guy has a 12 bolt, not a 14 bolt.

Thanks for pointing that out, my brain didn't process it properly when I read it I guess lol.

[SLDPULR]

Yes it's a 79 block high tin/high nickel 4 bolt main. I read the description when I picked the cam. I was originally building my 1969 as a street strip truck. I was just hoping that I would be able to get by with a 273 gear ratio. I still have not confirmed my gears yet. Going to try to do that this weekend.

In your opinion how much is it going to hurt that cam running a air gap over a Vic jr?