6 bolt cranks are cast and can handle a decent amount of power. Some have seen success with over 600 rwhp but you are assuredly on borrowed time. 8 bolt cranks can be either cast or forged so be sure which one it is before you buy. The main thing is to replace the weak factory rods and pistons if you are planning on making BIG power. But if you are willing to spend the money on a good set of rods and pistons, don't get frugal and just buy a forged crank also. Less headaches later on and the peace of mind is worth a lot.

 

Sweet, I got the pistons and rods upgraded already. Thats why i was trying to make sure the crank will work. thanks for the help

 

What exactly were your HP goals anyway?

 

The only difference with a cast 6 bolt, and a cast 8 is the flange. Strength is the same.

 

I thought the 6 bolts were for automatics and the 8's for sticks, no?

 

The reason I thought that is when www.karkraft.com had some original new mach motors for sale they said they had the 6 bolt cranks which were for automatics.

 

My hp goals for 450-500rwhp. And a 6 bolt can work for a T-45 cant it?

 

The crank has nothing to do with the transmisson. It only means how many bolts hold the flywheel to the crank. The flywheel is the only thing that matters. If you have a 6 bolt crank you need a 6 bolt flywheel. The stock crank is fine to 500. Probably more.

 

I think they use a steel crank in the Mach 1 manual. But I'm not sure. I could be mistaken. I really don't keep track of that stuff.

 

Stock GT 6 bolt crank is good to 7000 RPM's. If you don't twist it any higher than that you don't need a forged 8 bolt crank. Also be aware if you go to a 8 bolt crank you will have to buy an 8 bolt flywheel as well.

 

Just because I like to know I posted the question on the Mach 1 forum and what I got was that the GT's for the most part had 6 bolt cast cranks though the '99'/'00's(some) had 8 bolt cast cranks. Have never had my tranny off but if I get the converter I have sitting here installed I will see what my '99 has.
The Mach's did indeed have forged 8 bolts(Cobra's also of course) with sticks and cast 6-bolts with the automatics.

 

Windsor engines had the eight-bolt crank, Romeo's the 6 bolt crank. Count your valve cover bolts....11 Romeo....13 Windsor

 

Thanks for that bit of info! Is one preferred over the other for some reason? Blocks that is.

 

From what I understand the name just denotes where it was built. There are differences though between the blocks which makes some parts non-interchangable. There is no difference in durability that I am aware of between the two blocks.

 

There is no difference other then the number of bolts on the cranks. They are both just cast cranks. Ford has always been a royal PITA when it comes to parts being interchangable.

 

From the standpoint of the newer blocks that is correct, hopefully he doesn't end up buying a cranks from an early to mid 90's model as they had a different casting on the cranks. I believe the counter weight was larger and would interfere. Of course it's nothing a machine shop can't fix!

 

I have a windsor block and im putting romeo heads on it. So the 6 bolt is right isnt it?

 

The heads don't have anything to do with the crank.

 

I love how Ford just changes random shit all the time. They do this on all cars. It's got to cost them more money to make all these changes.

 

It's probably 6 to 1, half dozen to the other. They save money buy using left-overs, but machine work can be a PITA.

Can one use this as the rule?:

If it's a 6bolt crank, it's cast. If it's an 8bolt from a 2v it's cast, from a 4v it's forged.

Will that work? or were there older 8bolt 32V cranks that were cast? (IE lincoln MarkVIII)

 

All Mark VIII's were 6 bolt cranks...

 

Sullivan Performance says there were some 6-bolt Forged cranks but it seems no-one has ever seen one. By the way I have an 8-bolt that will be scrapped unless it is bought by somebody very soon and I will sell it cheap due to you paying the shipping should anybody want an 8-bolt Windsor from a '99 GT, cast of course. Make a reasonable offer ands it's yours. Cast or forged I have never heard of a crank breaking and most will never have the power to do so. The cast is lighter. Sure if I had a forged I'd use it but would not go out of my way to pay the extra for one being NA. This is a knife edged crank also. Mark

 

So I would need to change to a 6 bolt flywheel correct? and if I did that would I need to change anyother drivetrain parts?

 

Just the flywheel.

 

Sweet, Thanks for the help

 

6 bolt Romro 8 Windsor 0000 HP Difference!