need help on tall block gen5 427

[smokinflatties]

were do u get intake spacers , what rod do u use ,i only got block and steel crank, thanks

[fc-pilot]

Most performance shops should have intake spacers, and if not Summit, Competition Products, Doug Herbert, and such all have them. As far as what rod to use all depends on your budget. You could use a factory rod, but your piston would weigh a ton (literally). A factory performance 427 piston would work with a 400 long rod (6.535 length), but if you are going to buy longer rods anyway I might get a 700 or 800 long rod and get a piston with a shorter compression height to minimize the strain on the wrist pin as well as the piston. Then again, that is just my stupid thought as we won't try to get into the theory of long rod versus short rod. Those are just some options for you. I am sure before too long some of the other guys will jump in here with some other info.
Paul
I forgot to ask, what stroke crank do you have? That will make a difference.

[Fiat48]

Try to do a tall deck manifold as spacers are a pain.

[smokinflatties]

its the stock steel 427 crank , the rod & piston sounds like a pain in the a*@ is it worth the head ack or maybe i keep lokking for a 454, on the tall deck it uses longer push rods too?? do thay make a tall deck good intake how do i figger out the rod lenth / pin location of a good kb piston thanks

[smokinflatties]

Most performance shops should have intake spacers, and if not Summit, Competition Products, Doug Herbert, and such all have them. As far as what rod to use all depends on your budget. You could use a factory rod, but your piston would weigh a ton (literally). A factory performance 427 piston would work with a 400 long rod (6.535 length), but if you are going to buy longer rods anyway I might get a 700 or 800 long rod and get a piston with a shorter compression height to minimize the strain on the wrist pin as well as the piston. Then again, that is just my stupid thought as we won't try to get into the theory of long rod versus short rod. Those are just some options for you. I am sure before too long some of the other guys will jump in here with some other info.
Paul
I forgot to ask, what stroke crank do you have? That will make a difference.
the 6.535 rod and standerd 427 piston sould work ? that sound eser

[Jetaholic]

The stock rod used in all Mk IV and Gen V 427, 427T and 454 blocks looks to be 6.135" with a rod ratio of 1.63. The tall deck blocks used a 4 ring piston which took up the extra distance. A 4 ring piston with a 6.135 rod length would give the same .025" block deck to piston deck clearance in a tall block.
However, we're dealing with stock standard deck pistons in a tall deck block here. So a stock 6.135" rod length will not work here.
Now ideally you could add .400" to the stock rod length if you're dealing with standard 427 pistons with the stock pin height, which is 1.770.
Is the 427 piston a low performance or a high performance piston? Reason I ask is the pin height on both is different. Find out what your pin height is on the pistons you plan to use.
The 6.535" is for a stock pin height 427 piston (1.770"), and would also work for a 454 crank (4" stroke) on 454 pistons with the stock pin height (1.640"). For the high performance 427 piston, which has a pin height of 1.765, you would use a 6.54" rod.
Now here's where the confusion comes in. The standard 427 blocks ran a .015" block deck to piston deck clearance, while the 427T blocks ran .025" block deck to piston deck clearance.
Also, you can drop a 4" crank into a 427 block without clearance machining the block, and make it a 454.
So for a tall deck 427 block with a 427 crank with .015" block deck to piston deck clearance at TDC:
427 Piston (1.770" pin height (stock)): 6.535" Rod
427 Piston (1.765" pin height): 6.54" Rod
So for a tall deck 427 block with a 427 crank with .025" block deck to piston deck clearance at TDC:
427 Piston (1.770" pin height (stock)): 6.525" Rod
427 Piston (1.765" pin height): 6.53" Rod
Now just in case you decide to drop in a 454 crank, I did these next figures for you.
For a tall deck block with a 454 crank with the stock .025" block deck to piston deck clearance:
454 Piston (1.640" pin height (stock)): 6.535" Rod
454 Piston (1.645" pin height): 6.53" Rod

[smokinflatties]

u must do this for a living ,i dont have a piston yet so it up in the air what do u think is the better way on the deck hight.025 or .015 it is a 119cc cast head i wood like 11-1 conpresson 427 . thank alot jetaholic that helps me out alot is it had to find the rods u mention on the 427, i got a steel crank with the 427t 4-bolt so i will problele go that way, can u use a soild cam in a gen 5?

[Jetaholic]

u must do this for a living ,i dont have a piston yet so it up in the air what do u think is the better way on the deck hight.025 or .015 it is a 115cc cast head i wood like 11-1 conpresson 427 . thank alot jetaholic that helps me out alot is it had to find the rods u mention on the 427, i got a steel crank with the 427t 4-bolt so i will problele go that way, can u use a soild cam in a gen 5?
Well no I don't do it for a living, but I have quite a few books on the big block Chevy. A great book to get is published by SA Design, and it's called "How To Build Max Performance Chevy Rat Motors". Anything and everything you ever wanted to know about a big block, and even includes some motor math as well.
Summit Racing carries Eagle H-Beam 6.535" rods for $460. The next size down seems to be the 6.385" rods, which would be too short. So it would be easier for you to go with the 6.535" rods.
To answer your cam question, yes you can use a solid cam in a Gen V block.

[smokinflatties]

Well no I don't do it for a living, but I have quite a few books on the big block Chevy. A great book to get is published by SA Design, and it's called "How To Build Max Performance Chevy Rat Motors". Anything and everything you ever wanted to know about a big block, and even includes some motor math as well.
Summit Racing carries Eagle H-Beam 6.535" rods for $460. The next size down seems to be the 6.385" rods, which would be too short. So it would be easier for you to go with the 6.535" rods.
To answer your cam question, yes you can use a solid cam in a Gen V block.
thank you very much can i send u a beer or something lol thanks

[Jetaholic]

lol don't mention it. Maybe I'll see you out on a lake somewhere and you can get me then.