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· Sit N' Spin
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I found a Mark IV 4 bolt 454. Are these blocks any good?
As long as it's not cracked or bored to the limit hell yeah. There's more boats running MkIV blocks than there are GenV and VI.

Just remember, you cannot use GenV heads on a MkIV block, but you can use MkIV and Gen VI heads.
 

· Distinguished Member
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My biggest complaint with standard Mk IV blocks is (not the Bowtie) the head bolts go into the water jacket. If the block has much use on it, you'll get really good at helicoiling bolt holes.
 

· Sit N' Spin
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According to my big block Chevy book, studs are required -

Anything over 12.5:1 static compression ratio in a non-nitrous carbureted appilcation

A nitrous motor using heathy doses of nitrous (200hp shot and up)

A high boost supercharger or turbo charger application

As far as the bore, they can be bored 0.060" over safely. Anything over that and you may want to have it sonic tested for wall thickness before going over this.
 

· steelcomp was here
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Yep, have one with about 10 years of use. Two plugs, and 8 Helicoils. Plus replacement ARP studs because you ruin those too.

Jerry
After having to helicoil a couple holes on each side of one of my first engines (tighten...strip...pull head, drill, tap, install insert, reinstall head...shit...another one stripped! arrgh!) I finally pulled both heads and just did them all. Now I dip the end of the stud in a little Permatex and it slows the corrosion way down.;)
 

· steelcomp was here
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My biggest complaint with standard Mk IV blocks is (not the Bowtie) the head bolts go into the water jacket. If the block has much use on it, you'll get really good at helicoiling bolt holes.
Yep. That's definitely a "what the hell were they thinking" GM engineering moment...:)sphss
 

· steelcomp was here
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They were thinking "hey, lets follow Ford's small block brillant idea of running the water pump/timing cover bolts thru to the water jackets!
So you're syaing not only can't GM think for them self, but they can't even see a bad idea when someone else doses it?:)bulb:)sphss:)hand
 

· Sit N' Spin
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So you're syaing not only can't GM think for them self, but they can't even see a bad idea when someone else doses it?:)bulb:)sphss:)hand
Now that's some funny shit :D

Perhaps the best design idea GM ever came up wtih was the timing cover on the GM 2.8L motor. If the goal of the design was to ensure that the timing cover would not come loose, that design more than accomplished the task. :D
 

· Some guys never learn.
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626 Posts
So a question for future reference. If I end up rebuilding my 27 year old 454 that's never had the heads off. Should I just plan on having the machine shop heli coil the block? Or plan on using studs even for a low hp deal? Or both?
 

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So you're syaing not only can't GM think for them self, but they can't even see a bad idea when someone else doses it?:)bulb:)sphss:)hand
hil:)hil:)hil:) If your kid sticks a kitchen knive in a wall socket more than once, and cheats from the dumbest kid in the class during a test, you know he is destined to be a engineer for the BIG 3:)bulb



 

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Torque test

After having to helicoil a couple holes on each side of one of my first engines (tighten...strip...pull head, drill, tap, install insert, reinstall head...shit...another one stripped! arrgh!) I finally pulled both heads and just did them all. Now I dip the end of the stud in a little Permatex and it slows the corrosion way down.;)
I took a piece, (3x3") of aluminum about an inch thick and drilled it for a 7/16ths clearance hole. I use it to check threads before assy even starts. Put the aluminum on the block, insert a good quality bolt and flat washer, torque. If everything feels good fine. If threads feel marginal, helicoil/or Keensert while the block is bare....Ray
 

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Discussion Starter · #16 ·
Well I just went and looked at this motor and it has been in a fire. The crank didn't turn, the tb and dizzy was all melted. So with me know a complete tear down was need I offered the guy 250 and he didn't take it. He said 300. What do you guys think its worth?
 

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So you're syaing not only can't GM think for them self, but they can't even see a bad idea when someone else doses it?:)bulb:)sphss:)hand
Now that was funny... :D

Well I just went and looked at this motor and it has been in a fire. The crank didn't turn, the tb and dizzy was all melted. So with me know a complete tear down was need I offered the guy 250 and he didn't take it. He said 300. What do you guys think its worth?
You already offered more than I would have.....
 
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So a question for future reference. If I end up rebuilding my 27 year old 454 that's never had the heads off. Should I just plan on having the machine shop heli coil the block? Or plan on using studs even for a low hp deal? Or both?
The reason for the heli coils is from taking the engine apart to many times. It wears out the threads. Thats one reason for studs. I'm using a 75 block that I've had apart more times than I can count and still no heli coils. As for studs for the heads, I've been running 12.5 to 1 for 7 years with ARP bolts and no problems. If you're going to remove the heads a lot, then studs may be in your future. A buddy of mine used a block so much that he had heli coiled almost every hole.

Tim
 

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Well I just went and looked at this motor and it has been in a fire. The crank didn't turn, the tb and dizzy was all melted. So with me know a complete tear down was need I offered the guy 250 and he didn't take it. He said 300. What do you guys think its worth?
I bought a 454 block that had been in a cabin cruiser that burned and it got so hot that the pistons were melted and the aluminum timing -cam gear was melted, the carb had melted and ran down through the engine, the head bolts and main bolt had all stress relieved and you cold damn near take them out by hand. After the clean up and machine work,new studs and all, that block made one hell of a good piece, guess you could say it was well seasoned.
 

· mo balls than $cents$
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I bought a 454 block that had been in a cabin cruiser that burned and it got so hot that the pistons were melted and the aluminum timing -cam gear was melted, the carb had melted and ran down through the engine, the head bolts and main bolt had all stress relieved and you cold damn near take them out by hand. After the clean up and machine work,new studs and all, that block made one hell of a good piece, guess you could say it was well seasoned.
heat treated!:)devil:D
 
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