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KeithFink

Carb options for a 345 in a Loadstar

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Friends,

I have a new-to-me '72 Loadstar 1800 which has a 345 under the hood. Not sure if this engine is original to the truck, but it has a Carter Thermoquad carb which was (apparently) originally spec-ed for a Scout w/auto trans. Well, the plastic bowl section of the Cater TQ is cracked, so I'd need to find a similar core carb to furnish me with that part. Before I do that,  I'm wondering about other carb options and their pros and cons for Loadstar duty. 

Anyone have any suggestions? 

What carb _should_ be in a Loadstar 345?

Is there a reasonable/workable way for me to install a two-barrel carb on the existing 4-barrel intake manifold?

In the short time that I've owned this truck, the performance of the 4 barrel Carter TQ hasn't impressed me, but with no previous Loadstar experience, I don't really know what I could expect, either.

Thanks for anything you may be able to teach me!

Keith-

P.S. The truck in question can be seen here-

 

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Been quite a few years ago but IIRC (which is a crap shoot) my 78 1600 Loadstar had a two barrel Holly, I think a 2600. Had a 540 Allison transmission. Can't help much more than that. BTW nice truck.

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I have 2 of those trucks with the 345 and they have a holy  2 bbl carb.

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392s had a 4-bbl of some kind standard. The only time the 345 had a 4-bbl was the last Scouts to compensate for smog equipment.

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I had a  68 F1800 Loadstar years ago. It had a 345 with a 4 barrel carb. The guy I bought it from had bought a new or rebuilt 345 short block. Since the truck originally had a 392 with a 4 barrel, the guy installed the old manifold and 4 bbl carb on the 345. At least that;s the story he told.

DWF

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If they check the casting under the right side valve cover, the smooth area will have the engine size stamped in to it.  I may be wrong, the front axle almost looked like a 7500# axle instead of a 9000#  that i might think was under an 1800.

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In a Loadstar app, the stock 4 bbl is a Holley, vac secondary, square bore about 600 cfm. You will have to change manifolds or use an adapter plate. The thermoquads had all pretty much fallen apart 20 years ago, also not tuned right for a big truck. The 2 bbl truckshas a Holley 2300 350 cfm.

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I always swap the horrible Holleys out for a Ford Motorcraft/Autolite carb, 2bbl or 4bbl. A carb off a 351W is about right for a 345. Thermoquad was a great carb in its day, but they are prone to cracking. BTW the Autolites are 2100 and 4100's.

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There was a Detroit Diesel Fuel Pincher or was that later on the S-Series?

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Keith

      You might try to epoxy that carburetor bowl and may be able to salvage that carburetor.

      I just loved that video that your son made for us.   You have got a very nice looking and running truck.  I hope it performs as well as it looks.  For it's age there aren't many that look and run that good.    Also I would check under the front end of the right exhaust manifold,  on the engine block.  There will be a raised boss, on the block,  scrape and sand this boss clean,  you should see the Model number of the engine stamped there.  You may have a V8 392 engine in this truck.

      On another note, you asked for any suggestions.    The International SV series engines,   SV 266, 304, 345, & 392 , all are timed on number 8 cylinder.  You need  to know this and please be sure to tell you mechanic, or it will cost you or them a lot of time, aggravation, and money.   The reason that they are timed on number 8 cylinder is;  These engines are externally balanced, and the front damper has no metal in the position where the number 1 cylinder timing mark would be located.

      I don't have to tell you how I know this,  "I saw the video",  These engines are very hard to keep exhaust manifold gaskets and exhaust pipes from leaking.   When you get gaskets and donut rings,  I'd recommend getting another set just to have a spare.   They may be getting harder to come by.   Also when reassembling the manifolds and pipes,  I highly recommend using antisieze  on the threads and double nutting the flange to manifold bolts.  Especially if I may be the one to have to change them the next time.    

      If you even think you may have a hard time removing the manifold bolts, please do yourself a favor,  and get a torch and heat the head area where each bolt is threaded, red hot, before removing the bolts.

GT&T

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After all these years I find out why they time on #8! I always thought it was just another Cornbinder idiosyncrity.

 

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5 hours ago, R Pope said:

After all these years I find out why they time on #8! I always thought it was just another Cornbinder idiosyncrity.

 

Mr. Pope

       Thanks for that reply.    You made my day.  I hope others may have learned something from this as well.

Fred 

PS.    Thanks for the information about using a MotorCraft carburetor on these engines.  I remember reading this on here many years ago,  and you may be the one who posted it then.   Also both the 2 barrel and 4 barrel versions.

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On ‎5‎/‎12‎/‎2020 at 8:58 PM, lightninboy said:

392s had a 4-bbl of some kind standard. The only time the 345 had a 4-bbl was the last Scouts to compensate for smog equipment.

1974 California emissions scouts had a 4bbl standard. The 304 was not available in 1974 scouts sold in Calif.

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Around here most 345's had 4 barrels.

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The 1210 I restored years ago had a 392. I put an Edelbrock 600 on it, but had to buy the tuning kit and try lots of combinations before I found one that really worked. But, once that was done, it really ran well. Out of the box, it was overfueling, so I would assume that on a 345, that would be even worse. All the Scouts I had with 345's had 2 barrel's

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A holey 'spread bore' 4165 should fit on that intake manifold.  A 650 is the standard size for a '350' but a smaller cfm would probably have better bottom end.  A vacuum secondary will give better performance than the mechanical secondaries. You may have to get some small parts for the linkage, vacuum lines, etc.  Thx-Ace

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Thinking out of the box, I would get a TBI unit from a 454 Chevy 93-96 OBD1 and graft it on. That thing is so dumb that it is basically a 2 barrel carb. Use all the stock GM 454 parts and ECM.

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      I have a 345 in my 66 pickup .

     Most 345's  that I am familiar with in my neck of the woods had two barrel.

    In rebuilding my  345 I put a 392 four barrel manifold on it.

   I am running a Edelbrock  four barrel and love it .

    My old professional engine rebuilder and my engine mechanic both say Edelbrock is the quality to go with

       Tony

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