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View Poll Results: To swap or not to swap? | |||
Keep plugging along... |
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3 | 23.08% |
Swap that thing out! |
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10 | 76.92% |
Voters: 13. You may not vote on this poll |
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#1 |
Registered User
Join Date: Jun 2024
Location: Phoenix,AZ
Posts: 47
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Ok, I'm having straight forward decision making "funk" for lack of a better term. I need you all to help. Not so short back story: I've got a 1971 GMC K2500/flatbed, with a 350/ TH350/ NP205, Dana 70 dually rear-end, Dana 44 front 4.10 gears( Un-confirmed, that is what the "tag" on both axles says). I've already done a complete tune up(plugs, wires, cap, rotor, new HEI innerds, including weights and springs) rebuilt the Edelbrock 1406 that came with it and completely rebuilt the fuel system(tank, sending unit, fuel filter, fuel pump, fuel line to the carb) I've also replaced the starter and flex plate (both were missing teeth).I've also replaced mounts/lights/ and other aesthetic parts. .. At this point I'm getting frustrated... It will not time correctly or run smooth. I've tried finding TDC using a piston stop and it is way off(yes I rotated it by hand both directions and then found the middle) it will not stay "timed" I set it 12 dgrs advanced, shut of the truck, come back 10 mins later and it is "out" by 2 dgrs(either direction). There is also noticeable slop when turning the crank by hand to when the rotor actually starts turning. This to me tells me my chain/gears are toast and at some point I've developed a tick/tap in the driver's side of the engine that sound suspiciously like a lifter/valve/rocker or similar on #7.
**At this point I'm at a cross-roads.** 1) Do I continue to patch this possibly original ( I think the heads were replaced at some point) 53 year old engine "because it runs"? OR 2) Swap in a Factory GM long block "TBI" 350 crate motor that has been sitting in the crate since 2017? Any and all advice is welcome/appreciated. |
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#2 |
Senior Member
![]() Join Date: Dec 2009
Location: TN.
Posts: 8,097
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Re: Mental help needed, please.
I would say swap it out.
You will be time and money ahead.
__________________
________________________________________________________________________________________ ____________________________________________ 84 Chevy K-20 63 Impala (my high school car) http://67-72chevytrucks.com/vboard/s...Crew Cab Build |
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#3 |
Registered User
Join Date: Jun 2024
Location: Phoenix,AZ
Posts: 47
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This is actually the direction I'm leaning. I feel like I just need more experienced opinions than my own... Or put another way, "I value others (with more experience in this type of matter) opinions."
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#4 |
Registered User
Join Date: Aug 2020
Location: Jasper GA
Posts: 16
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Re: Mental help needed, please.
Swap it and get it on the road to enjoy. If it is the original engine you will still have it and you can take your time tearing it down and really seeing what you have.
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#5 |
Registered User
Join Date: Jun 2024
Location: Phoenix,AZ
Posts: 47
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Re: Mental help needed, please.
Valid point, thank you. I could tear it down and take my time rebuilding it the way I want for long term replacement... My wife is gonna laugh at me... I swore "no leftovers"
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#6 |
Registered User
Join Date: Aug 2009
Location: Bowser
Posts: 13,607
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Re: Mental help needed, please.
Tell us more about this tbi crate motor.
What’s the specs on it? I’d keep plugging along. You’ve got a running motor to learn stuff from. |
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#7 |
Registered User
Join Date: Oct 2016
Location: Dallas Texas
Posts: 3,090
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Re: Mental help needed, please.
.
Crate motor. -Kevin
__________________
67 C10 fleet fuel injected '70 402, 700r4, 3.73 posi 07 335 sport turbo 6sp 94 Trans Am GT LT1 6sp posi -- sold after 22yrs 99 540 sport V8 6sp -- sold 73 240z L24 4sp -- given to friend 68 C10 step 350/350 3.73 open -- sold |
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#8 |
Senior Member
![]() Join Date: Apr 2013
Location: Podunk, Texas
Posts: 748
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Re: Mental help needed, please.
This ^^^^^^^^^^^^^^
__________________
"It is hard to search for a black cat in a dark room, particularly if it is not there. Especially if this cat is smart, brave, and polite." Sergei Shoigu, Russian Minister of Defense |
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#9 |
Senior Member
![]() Join Date: Feb 2002
Location: Tucson, AZ USA
Posts: 7,263
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Re: Mental help needed, please.
You already have a Crate Motor. Use it.
__________________
Every 25 years I like to rebuild that 292, whether it needs it or not. |
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#10 |
Senior Member
![]() Join Date: Jun 2022
Location: San Ramon,CA
Posts: 504
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Re: Mental help needed, please.
It's your hobby. Spend your time, money and mental energy(aka "spoons") where you find them to be rewarding
__________________
1970 C10 Custom longbed 350/350 |
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#11 |
Born Psycho
![]() Join Date: Feb 2001
Location: brentwood,cal,usa
Posts: 4,881
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since the truck isn't original and unmolested I say do the crate motor and be driving it in a day or so. save your old one and build it up as time and $$$$ allow.
__________________
jerry moss 72 cheyenne super K20- tilt,tach,vacuum,speedwarning,buckets,shoulder belts,am/fm,tow hooks,bumper guards,toolbox,aux. fuel tank,posi front and rear,plus other goodies!!! SOLD 69 suburban K20-tilt,tach,vacuum,speedwarning,buckets,shoulder belts,am/fm,4 inch all spring lift,4 speed, 14 bolt full floater, dana 44 HD,warn winch,posi front and rear,tow hooks,plus other goodies. 73/80 chevy/gmc K20 SB400,turbo 400,205,tilt,a-c,gas hog. 77 K/5 cheyenne blazer-daily driver/beater. SON HAS IT NOW BRENTWOOD,CALIFORNIA |
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#12 |
Born Psycho
![]() Join Date: Feb 2001
Location: brentwood,cal,usa
Posts: 4,881
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since the truck isn't original and unmolested I say do the crate motor and be driving it in a day or so. save your old one and build it up as time and $$$$ allow.
__________________
jerry moss 72 cheyenne super K20- tilt,tach,vacuum,speedwarning,buckets,shoulder belts,am/fm,tow hooks,bumper guards,toolbox,aux. fuel tank,posi front and rear,plus other goodies!!! SOLD 69 suburban K20-tilt,tach,vacuum,speedwarning,buckets,shoulder belts,am/fm,4 inch all spring lift,4 speed, 14 bolt full floater, dana 44 HD,warn winch,posi front and rear,tow hooks,plus other goodies. 73/80 chevy/gmc K20 SB400,turbo 400,205,tilt,a-c,gas hog. 77 K/5 cheyenne blazer-daily driver/beater. SON HAS IT NOW BRENTWOOD,CALIFORNIA |
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#13 |
Registered User
Join Date: Jun 2024
Location: Phoenix,AZ
Posts: 47
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Re: Mental help needed, please.
It is a standard 350 crate motor (long block) from GM "designed for 87-95 TBI Gen 1 vehicles" which I think just means it is a standard 350 with TBI heads.
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#14 |
Registered User
Join Date: Aug 2009
Location: Bowser
Posts: 13,607
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Re: Mental help needed, please.
How complete is it?
Does it have a distributor, intake, roller or flat tappet cam, fuel pump push rod, etc. Bunch of things you gotta know before swapping. |
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#15 |
Registered User
Join Date: Jun 2024
Location: Phoenix,AZ
Posts: 47
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Re: Mental help needed, please.
After "googling" the part # you know as much as I do. Jegs has a "spec" sheet on the GM part # and so do a few other sites... One says it's a 2 bolt main replacement, another says it is a 4 bolt main. One says 195hp, another says 210hp. You get where I'm going with this. I personally have no clue, I haven't cracked the crate yet it is still in the plastic. It does look to have mounting holes for a mechanical pump... But no "hole" for the armature. It did come with a newer style (90s) distributor, external coil HEI type. That and a new water pump both in AcDelco and "GM" boxes separately. The water pump also has a AcDelco thermostat in side the pump box, but I believe that was put there by a human. I don't think it was a "GM combo pack".
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#16 |
Registered User
Join Date: Aug 2009
Location: Bowser
Posts: 13,607
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Re: Mental help needed, please.
What I’m angling towards is it might not be an easy swap.
You’ll need an electric fuel pump with a bypass regulator and fuel return line. Specs show a flat tappet cam. The distributor that came with it will have the right gear on it. Of course you’ll need to do a normal cam break in. And a pre-lube. Also possibly a different flex plate. And the water pump is likely a long one which requires different pullies. All kinds of things to consider. |
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#17 | |
Registered User
Join Date: Jun 2024
Location: Phoenix,AZ
Posts: 47
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Re: Mental help needed, please.
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#18 |
Registered User
Join Date: Aug 2009
Location: Bowser
Posts: 13,607
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Re: Mental help needed, please.
There you go, drill a hole, use a mechanical pump. Problem solved.
I did consider that but there are a couple pitfalls. A jig isn’t cheap. What rod to use that’s compatible with the cam lobe. Does the cam have a fuel pump lobe. Some don’t. You don’t absolutely need to have a return line. Pump’s can burn out faster if you don’t. I’m just trying to point out all the little things that can turn your weekend engine swap into your truck sitting idle for 6 months. |
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#19 | |
Senior Member
![]() Join Date: Mar 2019
Location: Herculaneum MO (20 minutes south of St. Louis
Posts: 617
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Re: Mental help needed, please.
Quote:
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67 C10 283 T5 swapped longbed fleetside = wife's daily driver 67 C20 292 (originally a 250)4speed longbed fleetside w/original wooden bed=my project truck 67 C10 283+.060 (so a 292 as well)T5 swapped longbed fleetside=my DD 72 C1500 Sierra Grande 350 TH350 longbed fleetside=wife's fair weather truck Can you tell we are fans of longbed fleetsides & 67s Chris |
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#20 |
Junior Member
![]() Join Date: Apr 2021
Location: Santa Cruz, NM
Posts: 99
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Re: Mental help needed, please.
You could change the manifold on the TBI engine and use a carburetor with an electric pump with no return line. It would be basically the same setup you have now, and the only additional electrical item to add is a relay from the switched source for the pump and choke. Otherwise, I believe there would be some sensors to add along with a computer.
Once you go that full TBI swap route, there would be no sense in going back to a carburetor because of all the other stuff you'd be removing. I think it's a matter of change to TBI now, or just enough to keep it going reliably. Invest a lot of time and effort now, or just enough until a later date of your choosing. I would choose a carbureted engine swap, with minimal time spent on it, and get to using the truck soon. |
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#21 | |
Registered User
Join Date: Jun 2024
Location: Phoenix,AZ
Posts: 47
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Re: Mental help needed, please.
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#22 | |
Registered User
Join Date: Jun 2024
Location: Phoenix,AZ
Posts: 47
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Re: Mental help needed, please.
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#23 |
Registered User
Join Date: Aug 2009
Location: Bowser
Posts: 13,607
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Re: Mental help needed, please.
You might get lucky seeing thru a drainback hole or pull the pan and look upwards.
I’m starting to think your best bet is sell the crate and buy a motor more suitable. One with a mechanical pump and a roller cam. |
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#24 |
Senior Member
![]() Join Date: Feb 2002
Location: Tucson, AZ USA
Posts: 7,263
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Re: Mental help needed, please.
I'll back Geezer on that. Vintage correct Crate Motors are available.
__________________
Every 25 years I like to rebuild that 292, whether it needs it or not. |
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#25 |
Registered User
Join Date: Jun 2024
Location: Phoenix,AZ
Posts: 47
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Re: Mental help needed, please.
I did a deep dive... And you guys are correct. I'm pretty sure the correct answer is sell the crate motor and get a "period correct" motor. It will be infinitely easier on my self and sanity in the long run. Thank you all for the suggestions and help. Now to wait... Cause I know I won't get msrp for this crate engine but I'm not giving it away either. You guys know. 👍
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