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#1
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Go Big 455 or not?
I have the original 389 out of my 65 GTO, It is a it has never been taken apart or bored over. I also have a 1971,455 complete engine that has never been bored over or any type of machine work done to it.
I want to build a strong street motor. Aluminum E heads, roller cam and rockers and so on.... The question is, do i buy a stroker kit for the 389 to make a 455? Or do i use the 455 to build the strong high horse power that i want? Is the 71 , 455 block a better / stronger casting than the 65 , 389 block? |
#2
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If it were my car, I'd remove the original 389ci and tuck it away. Then I'd sell the 455ci block and use the proceeds to buy a 400ci block and stroker kit to build a 461.
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1966 Pontiac GTO (restoration thread) 1998 BMW 328is (track rat) 2023 Subaru Crosstrek Limited (daily) View my photos: Caught in the Wild |
The Following User Says Thank You to ZeGermanHam For This Useful Post: | ||
#3
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that’s a lot of effort for a street engine just to go to a 3” main block, no? is the juice worth the squeeze?
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The Following User Says Thank You to i82much For This Useful Post: | ||
#4
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Maybe, but it depends. You can usually find good standard bore 400ci blocks for around $500, and Butler rotating assemblies start at $1800. OP says he wants to build a "high horsepower" motor (a subjective term). By the time you sell the 455ci block, it's within a thousand dollars difference (give or take). And with that in mind, I'd rather have the the 400ci block with the smaller/stronger mains and future-proof it to handle whatever power gets thrown at it down the road. And I assume he'd have to bore the 455ci block anyway, and then new pistons would need to be purchased, further narrowing the price gap.
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1966 Pontiac GTO (restoration thread) 1998 BMW 328is (track rat) 2023 Subaru Crosstrek Limited (daily) View my photos: Caught in the Wild Last edited by ZeGermanHam; 05-19-2021 at 07:16 PM. |
#5
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Yep 389 put to bed
Build that bodacious 455 |
#6
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Quote:
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#7
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But I don't feel very strongly about it either way. I think everyone is in agreement to put the original 389 on ice and build the "fun" motor using something else, whatever it may be.
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1966 Pontiac GTO (restoration thread) 1998 BMW 328is (track rat) 2023 Subaru Crosstrek Limited (daily) View my photos: Caught in the Wild |
#8
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NOPE. Useable 400 blocks are far more common than 455s these days. ALL stroker cranks will fit in a 400 block with minimal grinding. What you will have is a 3” main 455 with far lower bearing speeds, which is an Achilles’ heel of the 3.25” main Pontiac engines.
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“It takes considerable knowledge just to realize the extent of your own ignorance.” Dr. Thomas Sowell |
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#9
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If you are big time drag strip or roundy round racing sure. I have a 455 over 500 HP for years and years. One of the reasons it has lasted is I have refused to use any main bearings with only the single round oil hole in the middle. The shot of oil comes from the tab side of the 3 holes that intersect and if you do not drill a hole in your main bearing that oil has to hit the back of the bearing, mover over and go through the stock hole location. By that time the crank oil hole has gone by. Fine if a stock grandma,s station wagon but in a performance use you will starve your rod bearings at high RPM. I even drill our the race bearings with a oil slot vs round hole on 3" main bearings. |
#10
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Store the 389. Build up the 455. Two bolt mains good up to 600HP. Good advise from previous post.
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#11
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Personally I’d build the 71 455. You have it and it is plenty strong. Way cheaper to use the factory 455 crank and just buy rods and pistons. The end result in power and reliability will be the same only a lot cheaper than buying a 400 block and a “stroker” crank. The factory crank is probably stronger than the new cast cranks anyway despite its age. And there are all the parts that readily bolt right on the 455.
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#12
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Stash that original block - there is no since it risking it on a modified build.
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#13
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Let the 389 slumber under the garage work bench
and build the 455. 500 hp and 550 ft lbs should be cake even with Aluminum D port heads!
__________________
Wernher Von Braun warned before his retirement from NASA back in 1972, that the next world war would be against the ETs! And he was not talking about 1/8 or 1/4 mile ETs! 1) 1940s 100% silver 4 cup tea server set. Two dry rotted 14 x 10 Micky Thompson slicks. 1) un-mailed in gift coupon from a 1972 box of corn flakes. Two pairs of brown leather flip flops, never seen more then 2 mph. Education is what your left with once you forget things! |
#14
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My correctly date coded, '64 GTO 78XW coded, 389 is on an engine stand, complete carb to pan.
I found a standard bore 455 complete carb to pan for $500.00 and went that route for a 462. |
#15
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The engine now has aluminum heads on it vs the factory heads. I am going away from the solid lifter stuff and will run a flat tappet Hydraulic cam with Rhoads lifters otherwise I would leave it alone. . The engine has HO Try-Y headers. Remove the early engine and oil it up and store it away and go with the basic 455 engine. The car will be a enjoyment to drive and still perform a lot better vs the 389 engine. Tom V.
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"Engineers do stuff for reasons" Tom Vaught Despite small distractions, there are those who will go Forward, Learning, Sharing Knowledge, Doing what they can to help others move forward. |
#16
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I hope we get to hear about you driving the GTO, here one of these days!!!
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1977 Black Trans Am 180 HP Auto, essentially base model T/A. I'm the original owner, purchased May 7, 1977. Shut it off Shut it off Buddy, I just shut your Prius down... |
#17
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I vote with the crowd telling you to store the original engine and build the 455 with the factory crank.
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#18
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Another vote for store the original 389 and build the 455
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Chris D 69 GTO Liberty Blue/dark blue 467, 850 Holley, T2, Edelbrock Dport 310cfm w Ram Air manifolds, HFT 245/251D .561/.594L, T400, 9" w 3.50s 3905lbs 11.59@ 114, 1.57/ 60' |
#19
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Save the 389, build the 455.
For what you and the vast majority of us do its a waste of time, effort and money to build a "stroker" when a basic 455 is more than good enough. Once these stroker cranks showed up a lot of people thought there would be a major difference in power and reliability. There is not unless you are pushing the power level to beyond what a PMD block, any of them are safe too. And even then its not much. A 455 with iron heads are the best street engines around considering you do not have to do much to them to get it done right. |
#20
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A factory 455 block and crank with studded 2‐bolt mains is easily good up to 600Hp. Are you really going to build an engine that makes that much?
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---------------------------- '72 Formula 400 Lucerne Blue, Blue Deluxe interior - My first car! '73 Firebird 350/4-speed Black on Black, mix & match. |
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