25r and 25 differences

[billym9]

these look the same to me other than the cooling head, what else id diffferent

 

[itsalifeworthliving]

there is very little diffrence. i just swapped out the 2.5r in my revo with the 2.5 and the only diffrence i can see is slightly less torque. i think that they may be ported slightly diffrent

 

[Paul11277]

I'm not sure how true it is but i read on here that the main difference between the 2 is that the 2,5 is cast and the 2.5r is machined. Also found a mod for the 2.5 on google that said if you take the sleve out and polish it up and use a small peice of wet and dry paper around the port's you can really improve the performance. Some where on the same site it says that the 2.5 gets 2 stages less polishing than the 2.5r hence why if you do the mod to the 2.5 it is supposed to make a significamt difference. When my engine is due a rebuild i will be doing this but its not that old so will give it a miss for now. There is also a vid on you tube (if i remember corrcectly)showing how to do the mod.

 

[TWOCANE]

Its suposed to be the porting.

 

[SMaxxin]

The difference is the porting and a blue head.....The blue head is machined, the old head is cast. I ran both on the same truck and couldn't notice a difference.