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366 /427 chevy truck motors

45K views 12 replies 10 participants last post by  Double_v23 
#1 ·
what is the differance between this motors and other big block motors
 
#5 ·
Before the core price went through the roof on these engines, I used to buy them, take out the crank and rods and keep the main caps and send the rest with the scrap guy.

The 427 truck block is an excellent basis for a cheap stroker engine. If the block sonic tests ok, you can bore it .100 and put a 4.5" stroke crank in it for a 535 cu. in. torque monster. :D

Barry
 
#6 ·
366 upgrade/more torque

Hello, I have a 1991 366 on propane with an AT545 allison tranny inserted into a 1956 army 6X6. It runs great as the engine was replaced in the school bus just before I had purchased it and swapped it out. I was hopeing for more power/torque capabilities from this stock engine. A buddy of mine suggested installing an M112 Eaton blower and maintain a 7# boost. Sound great but also sound like a lot of modification to the intake. The blowers can be purchased cheap but definitely not a bolt on option. I am not very familiar with the parts family, heads, intakes, cams, etc, for this engine as I am with the small block chevy's. Any ideas of what I could do to this engine to obtain hopefully more torque as I am pushing heavy weight from time to time, it has a dump box on it.
 
#7 ·
Any big block heads will fit.It is the intake that is different.Because the deck is higher it moves the heads up and out making it necessary to use a tall deck intake or a spacer kit at about $100.00 to use a normal intake.It is a good engine but as stated expensive to build.If you could find a set of used heads with smaller combustion chambers and bigger valves this would be the cheapest way to increase torque and horse power. And of course the right cam for your application. Also headers should help because I think the stock exhaust manifolds are pretty restrictive and usually crack after a while of abuse. Also the push rods are longer than a regular BBC and the exhaust and intake push rods are different lengths instead of all the same like a SBC. Hope this helps.
 
#8 ·
To answer the original question.

The deck height is 10.2 inches instead of 9.8 to compensate for an extra piston ring, the crank and rods on the 427T are the same as a 427, the crank is the same stroke on a 427t as a 396 and 427 but the second counterweightis a little larger. The heads are interchangeable but the intakes on the 366T and 427T are wider to compensate for the extra height. THE ONLY DIFFERENCE IN PRICE IS IF YOU ARE CHANGING INTAKES. and that difference is the cost of the spacer kit you will need to adapt a standard 9.8 deck intake. If you are replacing anything else the costs will be comparable to building a standard deck BBC.

The 366 is pretty much only good for low end torque, the small bores cannot be made much larger. IF you have a 427T like stated above you can get big power out of it, but not any more than if you had a standard deck block unless you go with an expensive exotic rod and piston combination.

Good aftermarket pistons are available for stock type rebuilds at comparable prices. A decent set of 049 head castings are available and will be more than enough flow for a stock type rebuild.

The only aftermarket intakes available for tall deck motors are for high RPM race use and would not work well, but a dual plane RPM intake and some spacers will really wake it up.

How do I know this? I have built several in stock trim and stroked to 496 they are all quality motors but Big Blocks are naturally more expensive. Do your research and you can find an affordable, powerful combo that will put a smile on your face when you step on the loud pedal. :thumbup:
 
#10 ·
Thanks for the great info, I never new about the spacer deal. If I were to find a set of heads similar to what you had mentioned, would it make sense to install blower as long as it could be limited to approximately 7# boost. Just wondering if the engine internalls could take the extra pressure. By reading what you two have wrote, it looks like these engines can take it as long as the RPM's are kept lower. I like the idea of the blower, seems to make sense for power and dollars. Still seems like a lot of figurin though?
 
#11 · (Edited)
pasadenahotrod said:
They are truck motors, not hotrod motors. Stick with the real thing, 454, 396, 400. You're not souping up an old Uhaul are you?
They will make a very good hot rod motor,I had one in my pro street 57 Chevy,And it would fry the 18.5's at 50 mph.And that was with stock pistons .I went with the stock pistons because every where's I called they told me they had to be custom made for about $1.000.00 so I deck the block and shaved the heads,and put low cc heads.And made a very hot motor with a really nice cam.I wouldn't build the 366. :thumbup:
 
#13 ·
6x6er said:
Thanks for the great info, I never new about the spacer deal. If I were to find a set of heads similar to what you had mentioned, would it make sense to install blower as long as it could be limited to approximately 7# boost. Just wondering if the engine internalls could take the extra pressure. By reading what you two have wrote, it looks like these engines can take it as long as the RPM's are kept lower. I like the idea of the blower, seems to make sense for power and dollars. Still seems like a lot of figurin though?
A blower is never a bad Idea, just make sure you do your homework, you are right about limiting the boost, detonation is more likely on BBC's and they don't like it when you retard the timing.

I know that you said that you already have the 366T but since you already have it, open chamber heads like the 049 castings will leave your compression low and then if you add the blower you should see some gains. But if you just add the open chamber heads you may actually hurt your power by lowering your compression.

As far as internals go it all depends on what you have in there, some tall decks came with 4 bolt mains and forged cranks, you kind of have to get in there and see for your self.
 
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