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Discussion Starter · #1 ·
I was wondering which engine would be more powerful. I know the 400 has more displacement, but I've also heard that the 366 creates more power at lower rpms... I'm looking for maximum torque, which one would be better?
 

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it depends on what you want. For a steet car, race car, or hot rod use the 400. The 366 was a halfway descent truck motor, but is a dog, not realy that powerful, and harder to get performance parts, (diferent than the other big blocks). I wouldn't use it cause it ain't really a practical car motor.
 

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If you are talking about a destroked BB to get 366 cubes then thats a tough question. The true limiting factors to maximum horse power is the amount of air that you can pass through the heads.A destroked bb can use monster bb heads. If you are talking about 10,000 rpm then the destroked BB will make more power.If you are talking about the 366 truck engine then I would use the 400 small block
 

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The 366T was a raised deck motor (tall deck) that was used in schoolbuses and dumptrucks. It was the least powerful of the raised deck motors, had the smallest bore and awful heads. There was also a 427T and a 454T. Block deck height on a T deck was 10.200", whereas a standard deck BBC was 9.800".
You can use spacer plates on the heads to use a standard BBC intake manifold, but the fellows who have done it say they leak like a sieve.

Here's a thread I wrote after Dyno-Simming a 505 tall deck.....
http://www.hotrodders.com/forum/cheapo-bbc-505-tall-deck-grunt-motor-164014.html
 

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I was wondering which engine would be more powerful. I know the 400 has more displacement, but I've also heard that the 366 creates more power at lower rpms... I'm looking for maximum torque, which one would be better?
For tractor pulling the 400 will meet it's structural limits and fail sooner. The 366 is made from the git-go to work hard in big trucks and busses, the 400 was meant to move station wagons for less cost than a big block option.

Federal Mogul makes a .060 over piston which will give you 384 inch displacement engine, that's as far as it's practical to go size wise with this.

Bogie
 

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Discussion Starter · #11 ·
I'm just looking at these two because they are sitting around at home doing nothing. I was already going to go with the 400 but someone else suggested the 366.
 

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Another gent on this board years ago had a SBC on a tractor and wanted to know what he could do to kick up the torque so I laid out the combo to him.
Take your 400 and use the following pieces:
A Summit Racing camshaft with .210 duration and .440 lift part number SUM-1069
A set of small tube 1.5 inch primary headers.
A pair of 193 casting 350 TBI swirl port heads with steam holes drilled.
A dual plane intake.
A 2 barrel carb, a Rochester Dualjet perferred.
This combo will create stump pulling torque. The trick to it are the heads. The TBI swirl port heads swirl the incoming mixture at a very high velocity which creates neck snapping throttle response and monsterous torque.
The benefit here is they run out of breath around 4000 RPM due to the swirl port design simply can't flow enough to support higher RPMs and in this case is to your benefit as you would want to limit the engine to about 3000 to 3500 RPM, which is so low it wouldn't hurt the 400's bottom end.
Even so I'm not a gambling man I'd be willing to bet the 400 with the combo I just laid out would make just as much torque as the 366.
The benefits to this is big block like torque in a small block package and the small block is cheaper to maintain.
 

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If this O/P wanted the best of both worlds I have to ref back to what I said about getting a tall deck 427 and have you re-read Tech's link. Of course a scratch build,but a cheap torque/hp monster right where he needs to be in the rpm range for a pulling tractor.
 

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Thanks Gary however I am well aware of what the tall decks are capable of. Guys don't use them to build huge cube stroker motors for nothing.
I was simply saying what I suggested would compete with a 366 in torque and on the cheap. I did not mention competing against a 427.
Overall I was just throwing my idea out there as another option that he may want to try.
 

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Both the 366 and the tall deck 427 in OEM form where and are dogs not worth their wt. LOL-but you know hot rodders always figuring a way to change things................;):D

I do think the 427 as a stroker over shines the 366 in a broader curve.:thumbup:
 

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Discussion Starter · #18 ·
Double Vision - is there any difference between the 193 casting heads and 191? cause I actually have a pair of 191 heads on an old truck. I was curious as to why you suggest a two barrel carb? I know someone who has an aluminum intake with a holley 4 barrel. not sure if it is dual plane or not but how would this perform? Thanks for all the advice! I don't plan on revving it above 3500 so I like this combination
 

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The info I get says the 191 heads came on TBI 350's so they'll work just the same. Why I recommend a 2 barrel is for high velocity and high velocity promotes quick revving and torque development in the low RPM ranges.
However you can use a 4 barrel, I would recommend a Quadrajet. If you can't get a Quadrajet then I'd use whatever 4 barrel you can get. If you use a vaccum secondary carb, you'll more than likely have to play with the spring strengths to get it to where it will activate within the given RPM range. A Quadrajet would make it somewhat easier, as it has adjustable secondary butterfly tension so you can set it in seconds without having to take anything apart. On that combo I would only use a vacuum secondary carb, that way the engine decides how much airflow from the secondaries it'll need to get the job done. However, it may make it harder to control the RPM's as when the secondaries come in it'll want to rev higher than 3500 RPM. It's also the thought of limiting it to 3500 may not create enough airflow to even pull open the vacuum secondaries, but that's what vacuum secondary carbs are designed to do, to only give the engine what it demands in airflow so it's not over carbed.
 

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Double Vision - is there any difference between the 193 casting heads and 191? cause I actually have a pair of 191 heads on an old truck. I was curious as to why you suggest a two barrel carb? I know someone who has an aluminum intake with a holley 4 barrel. not sure if it is dual plane or not but how would this perform? Thanks for all the advice! I don't plan on revving it above 3500 so I like this combination
The 191 head was used on heavy duty Swirl Port 350's they are configurationally similar to the the 193 but use a larger 74-76 cc chamber volume to reduce compression from the 193's 64-66 cc chamber. Compression is easily restored to 193 levels by using a flat top piston with the 191 head.

Bogie
 
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