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73-87 Chevy _ GMC Trucks => Members Rides => Topic started by: rumblebox on November 09, 2018, 12:58:21 pm

Title: 74 K20 468 build...... finally
Post by: rumblebox on November 09, 2018, 12:58:21 pm
    I'm starting a new thread, since practically everything about the build changed.

    The engine that came out of the truck was trashed. The knock ended up being a loose rod cap, which ultimately introduced the #1 rod to the #2 cylinder.

    So i found a big block in a 79 Z28(i later acquired the rest of the car) that was supposedly a 496. We pulled the engine, and i tore it down at the house. It ended up being a 454....... with a broken oil pump shaft. The rings cam off in about 6 pieces each, but ths crank was barely scratched. Then i looked closer at the crank and saw that it was forged. Then i looked at the date on the block, heads, and crank, measured the bore and found that it was a standard 1973 454 from a truck. It also had 049 heads that were in way better shape than my old 781's with sunken valves. So i wasn't so aggravated anymore about buying a smoked engine for $400.

    The cylinders were pitted from sitting outside with water in them prior to being installed in the Camaro, but it still made .060 over. The heads needed a couple of valve guides and hardened exhaust seats, but they were fine too. The crank easily made .010" under. The thumb rods were fine too.

    I originally tried to apply LSX logic to this build and wouldn't really listen to anyone who told me to keep the compression down due to dogshit burn chambers, but i ultimately came around and built it very mild knowing it'll still make crazy torque and decent HP.

    -.060 over flat-tops instead of domes

    -no decking of heads of block was necessary, which i regret now that i know the pistons are .037" down the hole, making it 7.8:1.

    -"RV" cam

    -1 3/4" headers

    -air gap knockoff

    -Holley Sniper EFI

    -drilled block for parallel cooling
Title: Re: 74 K20 468 build...... finally
Post by: fitz on November 09, 2018, 05:55:14 pm
Sounds like it will be a great motor.
I'm a camaro guy as much as a truck guy.
Any pics of the 79 Z28?
Thanks
Title: Re: 74 K20 468 build...... finally
Post by: rumblebox on November 13, 2018, 04:50:29 pm
i had to rip pics off my instagram to resize them

Title: Re: 74 K20 468 build...... finally
Post by: fitz on November 14, 2018, 07:13:04 pm
You have a few cool toys.

Looking forward to seeing how you like the big block with the Holley efi, and to see what's in store for the camaro.
In the late 80's / early 90's I parted out more 78-81 Z28's than I want to admit too.
Title: Re: 74 K20 468 build...... finally
Post by: rumblebox on October 05, 2020, 10:43:46 pm
I don't really get on forums anymore, but here's an update. The 468 is really healthy, and I use the truck all the time on my off days.
Title: Re: 74 K20 468 build...... finally
Post by: rumblebox on October 05, 2020, 10:51:50 pm
I've installed a Hyperspark since this photo was taken.
Title: Re: 74 K20 468 build...... finally
Post by: Shifty on October 06, 2020, 09:31:58 am
Nice truck!
Title: Re: 74 K20 468 build...... finally
Post by: FlatBlack77 on October 06, 2020, 10:37:36 am
Hows she run? Plenty of oomph I imagine
Title: Re: 74 K20 468 build...... finally
Post by: JohnnyPopper on October 07, 2020, 01:14:45 pm
Nice rig!

What does this mean? "-drilled block for parallel cooling" ???
Title: Re: 74 K20 468 build...... finally
Post by: rumblebox on October 07, 2020, 10:40:05 pm
Hows she run? Plenty of oomph I imagine

It's pretty healthy for a low compression engine with a small cam. Enough to shred 35's in 3 gears.


Nice rig!

What does this mean? "-drilled block for parallel cooling" ???

The '73 engine was set up for series cooling, which is less efficient than parallel cooling. You drill a few holes in the deck and use a newer style head gasket that routes the coolant differently.
Title: Re: 74 K20 468 build...... finally
Post by: rumblebox on October 07, 2020, 10:44:18 pm
Got some new-used tires yesterday.
Title: Re: 74 K20 468 build...... finally
Post by: JohnnyPopper on October 09, 2020, 12:55:48 pm
Thanks, I'll look it up, I'm building a 383 right now.

What is the last item on your herd of vehicles?
Title: Re: 74 K20 468 build...... finally
Post by: rumblebox on October 12, 2020, 03:03:50 pm
Thanks, I'll look it up, I'm building a 383 right now.

What is the last item on your herd of vehicles?

A 2011 335 diesel. It makes over 400hp, 600tq, and it gets between 35-40mpg hwy with 30-35 mpg average.
Title: Re: 74 K20 468 build...... finally
Post by: JohnnyPopper on October 13, 2020, 01:47:55 pm
YIKES! What a beast!  ;)