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Lowbuck Shop/Race Truck Build

General engine tech -- Drag Racing to Circle Track

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vortecpro
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Lowbuck Shop/Race Truck Build

Post by vortecpro »

A few years back I decided to build a 1979 big ten Chevy truck, my goal was to teach my son how to build a fun driver with out spending a bunch of money, and more important out of parts most people would discard. So I bought this very rusty C-10 long bed for 900.00, we stripped the drive train out of it and cleaned it up. We had a few virgin 327s left over bought for a 302 build, so we built a 327, pretty much did everything backwards from how it should be done, but its been fun. So we built a 11.1 327 with speedpro pistons, we used a Isky 480/240/108 solid lifter cam with 462 fuelie heads with Performer RPM intake and 750 double pumper carb. I used reproduction Z/28 pulleys. The original long shaft Turbo 350 was rebuilt with a shift kit hooked to a 2 piece drive shaft (more on that later). Luckily my 79 being a Big 10 had a truck 12 bolt but has a 3.07 open carrier. So I'am at the point where I want to turn it up, and here are my plans.

1. Build a new truck 12 bolt with 5.13 gears, with a car bolt pattern
2. Replace the ridiculously heavy 2 piece drive shaft a aluminum one piece
3. Use lightweight rims front and back

I will post some pictures as the truck sits today before the modifications, along with my rear end build.
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Re: Lowbuck Shop/Race Truck Build

Post by Bwh998 »

Nice. I love squarebodies.

Working on an 84 model myself.
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Re: Lowbuck Shop/Race Truck Build

Post by af2 »

This is not the same Vortecpro we are used to.
GURU is only a name.
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Re: Lowbuck Shop/Race Truck Build

Post by travis »

You already have the GM “big car” 5 bolt pattern...same as impala’s, caprice’s, etc. It is a very common pattern.

The problem with a 1 piece driveshaft in these is the length. My 3/4 ton suburban has a factory 1 piece aluminum driveshaft and it isn’t exactly light, as it is 5”-6” in diameter. High driveshaft speeds with the length will whip and bow so you have to use a bigger diameter...and you will have plenty of driveshaft speed with 5.13’s.

Also, the 12 bolt truck rear end isn’t quite as strong as a 12 bolt car unit, so be mindful of that.
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Re: Lowbuck Shop/Race Truck Build

Post by Roundybout »

A few of the driveline sites offer calculators that can help you in the direction of a driveshaft. Depending on your tire size, a 1:1 ratio T350 and 5:13’s might be concerning depending on how high you plan to buzz it. Critical driveshaft speed is a function of the shaft’s length, material stiffness and tubing diameter.
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Re: Lowbuck Shop/Race Truck Build

Post by Monza355 »

Fantastic father and son project ! I saw the engine begin dynoed on youtube and it’s very stout ! What converter are you using behind it in the truck ? And what does a truck like this weight ?
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Re: Lowbuck Shop/Race Truck Build

Post by pdq67 »

FWIW, a 12-bolt tuck rearends pinion shAAFT IS A LOT SMALLER THAN A CAR 'S 12-BOLT ONE.

mY OLD '80 c/k 10 HAD ONE UNDER IT AS WELL AS 2.76 GEARS. iT ALSO HAD A 3.50 1ST GEAR sAG TRANNY IN IT.

PDQ67

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Re: Lowbuck Shop/Race Truck Build

Post by nxtruck »

If it were me, I’d rethink step #2. I went down this road with my 66’ C10. Was using it for mainly drag racing (434 sbc, th350, 12-bolt ) and thought I’d make an improvement by replacing that lowly 2-piece shaft with a custom built 1-piece unit. Turned out to be a mistake on my part. I had a nagging vibration at high vehicle speeds that was caused by the 1-piece bowing and whipping. I had a heavy-duty 2-piece shaft built, yanked that 1-piece back out, and replaced it with the h.d. 2-piece. No more vibration problems. Btw, my 66’ is a long bed.
Just my experiences.
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Re: Lowbuck Shop/Race Truck Build

Post by nxtruck »

Also, fwiw, I think your 12-bolt will be fine. My truck weighs 4000 with me in it and has been 1.45 60 fts. with the truck 12-bolt.
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Re: Lowbuck Shop/Race Truck Build

Post by vortecpro »

Monza355 wrote: Sun Jul 26, 2020 6:58 am Fantastic father and son project ! I saw the engine begin dynoed on youtube and it’s very stout ! What converter are you using behind it in the truck ? And what does a truck like this weight ?
ATI converter. Weight is 4000 pounds.
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Re: Lowbuck Shop/Race Truck Build

Post by vortecpro »

nxtruck wrote: Sun Jul 26, 2020 7:39 pm Also, fwiw, I think your 12-bolt will be fine. My truck weighs 4000 with me in it and has been 1.45 60 fts. with the truck 12-bolt.
The 1985 Nhra Stock C-10 low compression 350 combination have run 11.90s with 1.47 60s @ 3800 and change. I will try a OEM 5 inch shaft, if that doesn't work I will put the super heavy factory 2 piece back in there that goes every direction but strait.
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Re: Lowbuck Shop/Race Truck Build

Post by trmnatr »

vortecpro wrote: Sun Jul 26, 2020 7:48 pm
nxtruck wrote: Sun Jul 26, 2020 7:39 pm Also, fwiw, I think your 12-bolt will be fine. My truck weighs 4000 with me in it and has been 1.45 60 fts. with the truck 12-bolt.
The 1985 Nhra Stock C-10 low compression 350 combination have run 11.90s with 1.47 60s @ 3800 and change. I will try a OEM 5 inch shaft, if that doesn't work I will put the super heavy factory 2 piece back in there that goes every direction but strait.
Yes goes every direction but straight!

Mark what rear suspension you going with?
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Re: Lowbuck Shop/Race Truck Build

Post by 1980RS »

Look at that young racer getting after it. Mark will have another winner in his stable soon. Keep us posted, always enjoy your builds.
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Re: Lowbuck Shop/Race Truck Build

Post by Monza355 »

vortecpro wrote: Sun Jul 26, 2020 7:42 pm
Monza355 wrote: Sun Jul 26, 2020 6:58 am Fantastic father and son project ! I saw the engine begin dynoed on youtube and it’s very stout ! What converter are you using behind it in the truck ? And what does a truck like this weight ?
ATI converter. Weight is 4000 pounds.
8” i assume ? It will be great to hear how it will do on the strip !
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Re: Lowbuck Shop/Race Truck Build

Post by vortecpro »

trmnatr wrote: Sun Jul 26, 2020 10:53 pm
vortecpro wrote: Sun Jul 26, 2020 7:48 pm
nxtruck wrote: Sun Jul 26, 2020 7:39 pm Also, fwiw, I think your 12-bolt will be fine. My truck weighs 4000 with me in it and has been 1.45 60 fts. with the truck 12-bolt.
The 1985 Nhra Stock C-10 low compression 350 combination have run 11.90s with 1.47 60s @ 3800 and change. I will try a OEM 5 inch shaft, if that doesn't work I will put the super heavy factory 2 piece back in there that goes every direction but strait.
Yes goes every direction but straight!

Mark what rear suspension you going with?
Stock until I have to make a change.
Racing a NA NHRA stocker should be mandatory before any posting.
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