Junkyard C30 stepside work truck "build"

[66Submarine]

On a positive note, I managed to find a tool box for a full-size stepside truck. Very nice to finally have one!

[TJ's Chevy]

Sounds like valve train to me.

[66Submarine]

Originally Posted by TJ's Chevy

Sounds like valve train to me.

Runs fine up high.

[deejaaa1]

Originally Posted by TJ's Chevy

Sounds like valve train to me.

X2. had it happen on my 81.
also had a 307 in the 70 Chevelle. never missed a beat.
love your build. down to earth work truck. hope to have mine on the road one day.
also like the fender top work stations. white paint looks great.

[TJ's Chevy]

Originally Posted by 66Submarine

Runs fine up high.

All the more reason to think its valves. lol Idle fine....under load fine...but when cruising you get a little misfire....usually valves not seating perfectly. I've seen my fair share of rebuilt engines do that. My 305 V6 does that...under load its smooth and at idle its the same...but cruising along at 2000-2500 rpm there's a little pop here and there.......Valves.

[66Submarine]

Originally Posted by TJ's Chevy

All the more reason to think its valves. lol Idle fine....under load fine...but when cruising you get a little misfire....usually valves not seating perfectly. I've seen my fair share of rebuilt engines do that. My 305 V6 does that...under load its smooth and at idle its the same...but cruising along at 2000-2500 rpm there's a little pop here and there.......Valves.

No valve job was done on the heads, the valves all went back where they came from, seats and valve faces showed good contact, and when I hooked up a vacuum gauge the vacuum at a fast idle was so steady you'd think the needle was painted on. No problems there.

It only runs smooth at idle and WOT. Part throttle light/moderate load is like you left spark plugs out. If you go WOT it picks up and smooths out.

[TJ's Chevy]

Originally Posted by 66Submarine

No valve job was done on the heads, the valves all went back where they came from, seats and valve faces showed good contact, and when I hooked up a vacuum gauge the vacuum at a fast idle was so steady you'd think the needle was painted on. No problems there.

It only runs smooth at idle and WOT. Part throttle light/moderate load is like you left spark plugs out. If you go WOT it picks up and smooths out.

Some guys were also saying they'll misfire like that because the engine is carbed and not injected and getting that "perfect" a/f ratio. Weather that is true or not I don't know....my BBC is carb and it doesn't miss a beat at Any rpm. lol

[66Submarine]

Originally Posted by deejaaa1

X2. had it happen on my 81.
also had a 307 in the 70 Chevelle. never missed a beat.
love your build. down to earth work truck. hope to have mine on the road one day.
also like the fender top work stations. white paint looks great.

Thanks. The tables on top of the fenders are certainly very handy.

[66Submarine]

Originally Posted by TJ's Chevy

Some guys were also saying they'll misfire like that because the engine is carbed and not injected and getting that "perfect" a/f ratio. Weather that is true or not I don't know....my BBC is carb and it doesn't miss a beat at Any rpm. lol

If you have a lean (or very rich) spot somewhere in the fuel curve, but with the tuning somewhere on the correct planet it shouldn't be any issue at all.

[66Submarine]

After I posted this I took the still-warm carburetor off another truck and it ran fine. I then put the original Holley 600 off of this truck on that truck, which drove fine with it.

I put the carb back on this truck and it works fine now. Not sure what to make of it. I put the mechanical throttle linkage back on it and changed nothing else on the truck. The only thing I can come up with is that the mechanical linkage could be a ground to the carb/intake if the distributor somehow wasn't grounding, but I still don't get why it would run high up if that was it.

I'll have to investigate further and see if I can come up with anything. At least it works now...

[TJ's Chevy]

If it works ok you might wanna leave it alone. lol Eveytime I tried to investigate further I had problems again. lol

[jdl71]

Originally Posted by TJ's Chevy

If it works ok you might wanna leave it alone. lol Eveytime I tried to investigate further I had problems again. lol

x2

[66Submarine]

'65 Chevrolet C30 with "new" 307 SBC -...

[66Submarine]

Originally Posted by hotrod66

No longer looks like I belongs in a horror film I'm kinda sad now.but good job

Now it kind of sounds like it belongs in a horror movie...lol

[deejaaa1]

sounds nice and strong. any hiccups after the "fix"?

[66Submarine]

Originally Posted by deejaaa1

sounds nice and strong. any hiccups after the "fix"?

Hasn't done anything totally insane like that since. The carb needed/needs some tuning, but no crazy stuff.

General update copy/pasted from another thread FWIW:

It's the 307 out of my '68 Impala with 98,000 on it. I took it apart, cleaned it up, honed it, replaced all the bearings, new brass freeze plugs, moly rings, steel shim head gaskets for correct quench distance, double roller timing chain (to replace the BS nylon one with the nylon all shucked off), new oil pump, quickly smoothed the heads up a little with a die grinder (made me feel better?), and used a mild Elgin E860SM GM blueprint HO 305 cam (202/207@.050, 114LSA, .404/.414).

The Holley 600 and Performer RPM intake were already on it when I got the car, and some short GM chrome valve covers I had and a couple cans of Duplicolor DE1607 made it look less hideous. I used a HEI I had with some light advance springs and ended up with 20º inital for 36º total + 14º from an "AR-12" vacuum advance can.

It's just a very mild and inexpensive "build" that runs nice and should last a long time. It makes 16.5" of vacuum at idle and I haven't noticed any detonation on 87 octane.

The exhaust is some old 1.5" truck headers and dual 2.5" pipes (eventual BBC power?) kicked out in front of the rear tires with Summit turbo mufflers. So far no one has said it's too quiet...

It also did this the other day warming up:

Odd cold fast idle lope - YouTube

Apparently the factory carb jetting was way too lean (it hesitated pretty badly and the plugs looked like they were never ran in anything). Swapping the 65's out for some 68's yesterday made it run much better (still need to check what the WOT jetting is like). I also swapped the orange accelerator pump cam and 31 nozzle out for the smaller white cam and a 25 nozzle.

[TJ's Chevy]

The lope sounded kinda cool. lol

[66Submarine]

I bought a 4.10 SF 9.5" 14 bolt with a Gov-Bomb out of a '98 2500 this evening for $75. Missing one brake drum, but it seems to be in very good shape. Being from a 2wd 88-98 it's about 65" WMS-WMS like the OE Eaton, so my current tire and wheel combo still works.

(My narrow C&C FF 10.5" 14 bolt is currently still trapped under a motorhome, so I figured this one should fit the bill fine for now. I need to finally get around to swapping stuff...)

[Eric15chevys]

Nice score on the rear end. I like that axle. I have a 94 C2500 2wd as my daily driver. I would love the 4.10 gears in it. It has 3.08 in it right now.

[66Submarine]

Might as well make an update or two. I finally replaced the rear end a while back (well, six months is a while)...and not a mile too soon for my taste...lol. IIRC I moved the new rear end back 1" via another hole in the perches so I didn't have to mess with the driveshaft. The width was fine, no other problems.

[66Submarine]

Also finally wore out the remold 235/85's And got some new ones. Well...more "new" remolds, anyway...

265/75R16 "Claw" from Treadwright. The old ones got slid quite a bit and still went 40,000 miles, so I can't complain much. Used another set of 16x6.5 wheels; wouldn't really want to go any wider, but I think they work fine. I'd still like a wider wheel for better stability, but those aren't free like these were...sometime in the future. Probably should attack the fenders with a hammer a little bit, too. Running around 45PSI now with no load, seems to be good.

[66Submarine]

And I decided I wanted to make some changes to the 307, so I stuck the 350 I put together for my Impala in there yesterday to run it a while. Basic 350 .030 short block with forged flat top pistons, moly rings, Vortec heads, steel shim head gaskets for correct quench distance, $99 Performer RPM copy intake from Competition Products, 214/224@.050 white box cam from Summit (1103). Basically the CT350 350HP/390TQ GM crate circle track engine with another point of compression. Inexpensive combo that should last a long time and run well for a daily driver.

[66Submarine]

Ended up with my wiring stuff all an hour away (oops), so I did some Roadkill engineering and used my pocket knife, tape, cable ties, and some wires I got out of a garbage can to extended the alternator harness using lineman's splices. Unfortunately, it still might be better than any PO wiring I've found...lol

[Deer_hunter_088]

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[66Submarine]

Clip of new 350 running:

You Tube