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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.
__________________
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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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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#4
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Stash that original block - there is no since it risking it on a modified build.
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#5
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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! |
#6
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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. |
#7
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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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#8
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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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#9
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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. |
#10
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Yep 389 put to bed
Build that bodacious 455 |
#11
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Quote:
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#12
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Quote:
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 |
#13
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Another vote for store the original 389 and build the 455
__________________
Chris D 69 GTO Liberty Blue/dark blue T400, 9" w 3.50s, 3905lbs 461, 850 Holley, T2, KRE 310s, Comp HR288 w 165s, RA manifolds, 11.60@114, 1.58/60 The spare: 467, 850 Holley, T2, Edelbrock Dport 310cfm w RA manifolds, HFT 245/251D .561/.594L, 11.59@ 114, 1.57/ 60' |
#14
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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. |
#15
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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. |
#16
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Ok, the winner is the 455! Thanks guys for your input.
i'll bet this next question might be all over the board. Heads, any and all opinions welcome. I am partial to aluminum heads. Your thoughts? |
#17
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Good decision. The stroker builds are only necessary when you don't have a 455 available to you. You solved that problem.
On heads, you'll have to weigh the cost factor for yourself. I've found redoing 50 year old cast iron heads is a very expensive venture. I generally don't get a pair out of a machine shop for less than $1000 and that's without port work. By the time you buy seats, guides, springs, retainers, valves, and then pay for all the machine work, new guide work, seats and valve job, cutting for positive seals, etc...to have an iron head that flows maybe ~220 cfm, unless you want to spend more for porting, The aluminum heads start to look like a pretty good bargain I usually do the iron heads for numbers matching type of stuff. |
#18
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Given your trans and gearing, destroking a 455 might be an option.
Pontiac was working on a production 366 roundport motor that "hit the sweet spot" according to engineers but could not get it past marketing. IIRC it had the bore of a 455 but a much shorter stroke. If you are running a 4 speed and 3.55's it may be a much better match. |
#19
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Can’t go wrong with Kauffman, Edelvrock or the Speedmasters. The E heads are tried and true. The Speedmasters are a little less money but flow a little more than the E heads out of the box I think. But horsepower is airflow and the Kauffman high ports flow 330 out of the box. That would be my choice. They can be Cnc ported relatively cheaply by Kauffman. The E heads can too. I had a set of cnc ported by Butler that flowed 340. Very nice too but still I would go highports.
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#20
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Been there done that!
I chose to do the 389 in storage and build a iron head 455 - 30 over. 4 speed and 3:55s. Been a really fun car to drive. Did similar in another car and over cammed it for street use. Live and learn. Good luck
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