1pig24

I made a similar switch in a 75 RS700L from a 2 valve to a E7400, the biggest issue I ran into with my truck was we had move the radiator back for a front mount intercooler because my old motor had a tip turbine. Otherwise I can not remember other big issues, oh yeah motor mount was different on the front mine had the old style front motor mount and we had to switch it to the newer one to match up with the E7

did you just simply modify your front crossmember or is there a western crossmember that will bolt up. Shouldn't be that hard to fab somethin up. I'm already set up with front air2air.

The O.P. said:

The E7 mechanical engines have the compressor in the same place as the E6 - buried down on the right rear.

yes it is, along with the married power steering pump. are the accessory drives the same bolt pattern, size, etc.?

Physicly pretty much the same depending on what truck the engine is coming from!

First big problem you may encounter is the front mount.RS is cradle mounted on the front cover!The e7 has a bolt on mount!

compresors differ sum .Water pump s differ from model to model!

With out setting em side by side !I'd be sceptical anything is possible with a little time thou!

I could for see lots of little and some big glitches!The RS did come with a 4 valve e6 at one point just before they did away with the model!

not to worried about the little stuff. I have all winter to work the glitches out. mostly concerned with physical dimensions. dont want to cut firewall out or have to move radiator. Thanks for your help. Love this site.

I have an 86 rs688ls with e6 350 2v. it has front air to air and fuller 10sp trans. I would like to upgrade to e6 4v or e7 mechanical with jake brake. will my accessories bolt up? is the physical size of the blocks the same? Any other engine suggestions?