Can you put 4" lift blocks on the front axle  of a 87 chevy
4x4  

NO!!!

Using blocks on the front axle of any vehicle is EXTREMELY dangerous.

Spend the money and lift it properly.  

Thanks....  Now maybe my Friend will beleve me. i told him that you can't use blocks on the front end only add new leafs. he told me i was NUTS  

here's a page for you on the topic...

http://128.83.80.193/scarysteering/scarysteering.html  

Thats scarey!!!!!!!  

I just want to add this.... technically a person CAN put blocks of any size under the front axle (I've seen this done before) BUT, IF YOU don't know what you are doing or IF YOU think you know what you are doing but in all reality you don't, just simplify the entire "lift install" and ask a professional before you get the lift laws even more strict than they already are or possibly NO LIFTS ALLOWED! The people that half-ass their rides need to be getting more experience from the guys that DO know how to do proper build-ups of any kind. Sorry if any out there is offended by this, just stating some facts for the safety of others.  

You should NEVER use blocks in front in any scenario. Front axle sees a LOT of twisting force from braking. Blocks amplify the effect of this and cause it to twist more and effect stability.  

You'd be driving down a winding canyon road and half way through the turn your truck ends up not turning anymore and off the road and down into the deep dark ravine you go. The front axle is no longer attached to the truck. Hell, its still at the top where the road is. You'd wish now you would've put SPRINGS instead of blocks in the front. Damn cheap ass!  

" DAM CHEAP ASS "     That's Low  

And what do you mean by the "CHEAP ASS" Thats low? I'm just stating facts. I know there are many people out there that think they can just put a block in the front to "save" money to lift their truck. I am entitled to my opinion and I can express it to certain levels and I was being nice about it. I could've put it really nasty and we aren't going there. Anyone that has questions about there rides, they ask them here and others, like myself, have knowledge and experience in mechanics and do it for a living, so yes I would have to comment on someone telling there friend that you can put blocks in the frontend, regardless if it is a little bit on the rude side. I have to laugh from time to time when I hear or read about certain things such as this question about blocks in the frontend. I give rbryant0 credit for being smart enough when he was possibly in doubt about the lift blocks in the frontend, atleast he asked for help and went to the best fourwheeling site to get the answer. There is a few guys on here that know what they're talking about and it is good to know that they, and others can and will give good honest answers and ways to fix their problems. Thanks to all of you that understand.