putting 4.6 crank in earlier block

neal1980 · Post by **neal1980** » Tue May 22, 2007 3:52 pm

Im sure this has been covered before, anyone know how much i should be looking at paying for somebody to machine my large journal 4.6 crank to fit my earlier 3.9 block. Is this all i need to do then use the 4.6 rods and pistons??

Ive read I may have to grind a bit out when its turning im ok with that.

Or can anyone recommend a place to do it, distance no object really as i have a good courier just want it to be spot on.

Cheers

Neal

ihatesissycars · Post by **ihatesissycars** » Tue May 22, 2007 4:11 pm

It depends on what 3.9 block you have.

If you the first of them then you need to have the mains turned down and loads of material machined off the counter weights and then a rebalance with lots of heavy metal put in.

The second/middle type just needs the mains turned down.

The third and last of the 3.9 blocks is basically a 4.6 block just not cross bolted (but has the provision to do so) and has the same size mains as the 3.9 block. This one you can either just turn the mains down and in it'll go or you can have the the block line bored and the holes drilled and tapped for cross bolting at the same time and again in the crank will go.

If you have the first type of block then its a gamble in regards to if it can be rebalanced after counter weight machining. Or so i've been told. I wouldn't bother if you have that one. It'd be cheaper to get a crank from JE made to suit.

Boosted LS1 · Post by **Boosted LS1** » Tue May 29, 2007 11:23 am

Or, instead of removing loads off the crank journals you could line bore the block and mill some more bearing locating slots.

Boosted.

ihatesissycars · Post by **ihatesissycars** » Tue May 29, 2007 11:26 am

Do you know anyone that can do that Mike?

Boosted LS1 · Post by **Boosted LS1** » Tue May 29, 2007 11:34 am

I'll check and post later today. I should be able to do it.

ihatesissycars · Post by **ihatesissycars** » Tue May 29, 2007 11:41 am

Wicked! I need it done to my spare block!

Post by **Coops** » Tue May 29, 2007 5:48 pm

me too possibly

neal1980 · Post by **neal1980** » Wed Aug 01, 2007 1:54 pm

any updates on this ????

ihatesissycars · Post by **ihatesissycars** » Wed Aug 01, 2007 4:03 pm

I'm not anymore, I still have the spare block but I've sold the crank and rods.