Recommended 4bbl carb for stock 318

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Hang on,spacers have been shown to make power
Sure - often they do. He's talking about an adapter. An adapter plate is more likely to be problematic. A taller spacer type adapter is still a roll of the dice - except unlike straight spacer - yer stuck with it.

They will for sure make power (it my me vey little) if they are clean flowing (no lip restriction) or they flow enhancing. Increasing the space or distance between the carb and runners allows for better atomization. But you can only go so far.

As for an adapter or riser get flow enhancing type... And I say flow enhancement because both adapters and risers nave all different kinds if inside machining. Such as a strait adapter plate would match the carb square base plate and pass strait through to the intake. vs. High flow adapter which will be machined to match the intake bore and the carb base and then the machining in between can be a polished and rounded, like the one I have. Risers have the same options in such that they are matched for a specific situation but the machining as well as material can make a big difference. I had a thread about spacers and adapters a while back and there was a lot of good info.
 
They will for sure make power (it my be a very little increase) if they are clean flowing (no lip restriction) or they flow enhancing. Increasing the space or distance between the carb and runners allows for better atomization. But you can only go so far.

As for an adapter or riser get flow enhancing type... And I say flow enhancement because both adapters and risers nave all different kinds if inside machining. Such as a strait adapter plate would match the carb square base plate and pass strait through to the intake. vs. High flow adapter which will be machined to match the intake bore and the carb base and then the machining in between can be a polished and rounded, like the one I have. Risers have the same options in such that they are matched for a specific situation but the machining as well as material can make a big difference. I had a thread about spacers and adapters a while back and there was a lot of good info.
 
Reality is there is more going on and so there no guarentees. An engine is not a continuous flow device. Different combinations will like different things at different throttle openings and rpms. When there is black residue up into the intake and onto the throttle blades that's pretty good evidence of the pulses and also the flow reversals that can and do occur most noticibly at the lower rpms.

Adapter plates can be problematic because they are thin. This is seperate from whether the discontinuities will effect flow characteristics or droplets shearing etc. Its a question of whether the bearing surface will stay stay sufficiently flat to have decent clamping on the gaskets. Using a stamped plate with an intake with big gap between the sealing surface and the bolts, like the stocker pictured in this thread, is more likely to have have trouble sealing.
 
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I have the same intake as the OP

it does say it does not fit the 4 hole spread bore intakes which i dont have anyways.

Either you do or don't. If you have this intake, its a spreadbore.
intake-manifold-2-jpg.jpg

* A Thermoquad or Quadrajet will be a direct fit.
* So will a Holley spreadbore replacement, but they are oddball carbs and best for people who like to experiment.
* If you have a Holley 1850, and it physically bolts on (dual stud holes in each corner of the base), then you still need to check that the throttles will open without interference and the mating surfaces seal bores and the PCV connection etc.
 
Either you do or don't. If you have this intake, its a spreadbore.
View attachment 1715228562
* A Thermoquad or Quadrajet will be a direct fit.
* So will a Holley spreadbore replacement, but they are oddball carbs and best for people who like to experiment.
* If you have a Holley 1850, and it physically bolts on (dual stud holes in each corner of the base), then you still need to check that the throttles will open without interference and the mating surfaces seal bores and the PCV connection etc.
Yes that is the intake I have!! I was referring to the 4 hole 340 intake that i dont have. Mine is the one you pictured not the one like I pictured.

DSCN0449.JPG
 
Yes that is the intake I have!! I was referring to the 4 hole 340 intake that i dont have. Mine is the one you pictured not the one like I pictured.

View attachment 1715228563
Easiest would be to see if you can find a T-quad thats a good match for your 318. Someone posted RustyRatRod might have a T-quads for sale. Send him a PM.
 
I'm not sure if you seen the new thread started on the Edlebrock carb? take a look, I have a feeling it could become a battle ground if people keep disagreeing to the disagreement. Ha
So far the comments are mostly an indicator of people's attentions spans. :lol:
 
Okay…..:realcrazy:
I completely forgot to post the finishing steps of the upgrade. So here we go
Initially I asked about a recommended carb, and received lots of feed back and recommendations.
It would seem the best carb to go with should be based on the final point of your upgrades, basically cams, intakes, exhaust heads, etc. When this is taken into account you will have a required CFM range needed and with that, internal carb parts can be swapped to maximize your requirement. Some of the parts will point you direct to an stock Edelbrock's or Holley's, to Demon's and Quick Fuel's. But when it comes to all the recommendations for a car with just a basic upgrade like just an exhaust or cam or intake maybe a combo. For ease of install an tuning it looks like an Edelbrock may be best, cost may be Holley, and original looks may be Thermoquad. In any case the basically have the same performance, however the Thermoquad has smaller primaries for better economy at lower rpm, and larger secondary's for reaching faster high rpm but this is a trade off for old technology an very difficult tuning. As for the Holley it's a bit difficult to tune and has a lot of parts for possible issues. And finally that Edelbrock… Because it is easy to install, has the fewest parts and most basic internal system that makes it the best for tuning. Easy adjustments, easy to change internal upgrades if needed, easy maintenance.

As for mine, My end goal is a stock look with a little extra. So a stock bottom end with stock heads and a mild cam and shorty headers with dual exhaust. Since it's a 318 to maintain a semi stock look it was the spread bore intake manifold and I would like to use a Thermoquad with that look.
But I only have so much money and am having to do all these upgrades in many steps. First was the exhaust with a dual 2.5'' and then a 4BBL is needed. Since I am still looking for a complete Thermo to rebuild, So I used a Holley (part #9834) known as a newer 4160 has a single inlet with electric choke that I already had sitting around. Below are the pics of the upgrade. Holley offers a direct bolt on kit for Plymouth if needed, but I bought the universal install kit and ended up not needing it. Although I did make a very easy offset riser bracket for the throttle cable that bolted onto the existing bracket and used the original lock down on top.
As for the pic with the arrows. If you were going to use this manifold and never put a spread bore back on you should completely round down all the center edges to ensure you get the best air flow.

Thanks for all the info from everyone:thankyou::thumbsup:
And I hope this gives a reasonable wrap up to help others in the future.

Factory Spread Bore Upgrade #1.jpg


Factory Spread Bore Upgrade #2.jpg


Factory Spread Bore Upgrade #3.jpg


Factory Spread Bore Upgrade #5.jpg


Factory Spread Bore Upgrade #7.jpg


Factory Spread Bore Upgrade #8.jpg


InkedFactory Spread Bore Upgrade #2_LI.jpg
 
Major reversion going on with that carb at some point , too rich ehh?

Carb clean it before the permanent install, check pv "more than likely has PV protection" for correct rating.
Wondering about the cam now. Lol
 
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Good point. Backfiring or major reversion. Definately agree. Clean that carb and especially the internal passages, which is pretty easy with a 4160.
 
Major backfiring going on with that carb at some point ehh?

Carb clean it before the permanent install, check pv "more than likely has PV protection" for correct rating.
Wondering about the cam now. Lol

Yeah I should have said I took it apart after the original install to show what I did, I just took the pics last week.
Back fire, OH YEAH. Super lean, it took a bit of adjusting to get it going. As it is I'm still tuning it to run just right.
Ha, I'm no tuner and this is why all factors need to be taken into account, cost and availability for me.
 
Backfire through the carb is ignition before the valve is fully seated. Makes sense. Right? Easy to remember if you think about it.

Just noticed in the mockup the transmission's 'kickdown' is all the way back. In actual use, make sure its forward so throttle opning increases pressure in the transmission throttle circuit.

Experience is a good teacher. You'll get there!
 
Okay…..:realcrazy:
I completely forgot to post the finishing steps of the upgrade. So here we go
Initially I asked about a recommended carb, and received lots of feed back and recommendations.
It would seem the best carb to go with should be based on the final point of your upgrades, basically cams, intakes, exhaust heads, etc. When this is taken into account you will have a required CFM range needed and with that, internal carb parts can be swapped to maximize your requirement. Some of the parts will point you direct to an stock Edelbrock's or Holley's, to Demon's and Quick Fuel's. But when it comes to all the recommendations for a car with just a basic upgrade like just an exhaust or cam or intake maybe a combo. For ease of install an tuning it looks like an Edelbrock may be best, cost may be Holley, and original looks may be Thermoquad. In any case the basically have the same performance, however the Thermoquad has smaller primaries for better economy at lower rpm, and larger secondary's for reaching faster high rpm but this is a trade off for old technology an very difficult tuning. As for the Holley it's a bit difficult to tune and has a lot of parts for possible issues. And finally that Edelbrock… Because it is easy to install, has the fewest parts and most basic internal system that makes it the best for tuning. Easy adjustments, easy to change internal upgrades if needed, easy maintenance.

As for mine, My end goal is a stock look with a little extra. So a stock bottom end with stock heads and a mild cam and shorty headers with dual exhaust. Since it's a 318 to maintain a semi stock look it was the spread bore intake manifold and I would like to use a Thermoquad with that look.
But I only have so much money and am having to do all these upgrades in many steps. First was the exhaust with a dual 2.5'' and then a 4BBL is needed. Since I am still looking for a complete Thermo to rebuild, So I used a Holley (part #9834) known as a newer 4160 has a single inlet with electric choke that I already had sitting around. Below are the pics of the upgrade. Holley offers a direct bolt on kit for Plymouth if needed, but I bought the universal install kit and ended up not needing it. Although I did make a very easy offset riser bracket for the throttle cable that bolted onto the existing bracket and used the original lock down on top.
As for the pic with the arrows. If you were going to use this manifold and never put a spread bore back on you should completely round down all the center edges to ensure you get the best air flow.

Thanks for all the info from everyone:thankyou::thumbsup:
And I hope this gives a reasonable wrap up to help others in the future.

View attachment 1715251814

View attachment 1715251815

View attachment 1715251816

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View attachment 1715251818

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THat transmission kickdown linkage is all wrong. I hope you adjusted it properly after getting everything bolted up.
 
THat transmission kickdown linkage is all wrong. I hope you adjusted it properly after getting everything bolted up.
Oh I know it has to tighten up, I haven't driven it and as I said I'm still trying to get the carb dialed in. Also for me it helps keep from pushing the rod back and forth constantly while doing adjustments. There are a lot of adjustments on this Holley you need to have the throttle wide open for so I just haven't bothered to adjust the kickdown yet. I didn't think of doing it before the pic or mentioning it in the post. Sorry, my bad
Thanks for pointing that out. Someone else could have used that as a reference at not know about the kickdown position. That can be damaging to the transmission if it's in the wrong spot it needs to be perfect or not attached at all to prevent damage. And on mine it does have to be readjusted because of the change in height. I guess it should also be noted there is a second type of linkage which is a 3 piece which requires different adjustment (I don't know that type).

Wow
I guess it's not as easy as I thought to wrap something up. It is easy to forget to mention all the explanation info and adjustments that need to be made. I'll take new and better pics of all linkages after I get a chance, hopefully tomorrow.
 
Backfire through the carb is ignition before the valve is fully seated. Makes sense. Right? Easy to remember if you think about it.

Just noticed in the mockup the transmission's 'kickdown' is all the way back. In actual use, make sure its forward so throttle opning increases pressure in the transmission throttle circuit.

Experience is a good teacher. You'll get there!
Haven't bothered to adjust the kickdown since I'm still trying to dial in the carb, sorry sould have mentioned that.
Most likely timing or something of that nature, but...
According to Holley and the troubleshooting section for backfires, there is more than valvetrain issues that can cause backfires.
It could be anything from faulty egr valve, ignition coil, plugs, plug wires, ignition timing, valve timing, vacuum leaks, also worn or damaged valve train parts, even choke. Most common being the timing.
This happened before the car even had a chance to warm up for the first time
For myself it seemed to be overly lean, which may have been caused by only having 10v to the choke and it was to the max on lean which I didn't notice.
 
Sell the Holley and get a good carb with the proper linkage and all your problems will go away. If you don’t adjust your kickdown correctly you can ruin your transmission in short order.
 
Holley and backfire don't play well together. Bad on power valves.
 
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