I have a 500 EFI that had a crack in both heads. So I got a set of castings to replace the cracked ones. We had a machine shop switch everything over from the old heads. After installing the heads we went to install the intake and it will not seat. It hits the lip at the top and will not seat. Does anyone know if there are any different castings on the 500 EFI that would prevent them from seating? Are we doing something wrong? The heads bolted right up, any help would be appreciated.

did you mill the new heads? If so, you have to mill the intake too

Yeah, sounds like the new heads have been milled. The only way to know for sure is to pull one off and cc a chamber. The intake can be cut to fit, but the heads will raise your compression. This should not effect your tuning to much, but it may need to be fine-tuned, depending on how much the compression has changed. Raising the compression does not change the tune like changing a cam or changing heads, but it does have an effect. Hope your shop can tune a MEFI. If not, give me a call.

Thanks guys we did confirm that the heads had not been milled. But the block had been decked which would change the geomtery also. We will just have the intake milled.

Thanks for the responses.

Hey Jeff
How did everything work out ?

Got both engines back in, should be ready to fire them up tonight.

Sure wish I could fire mine tonight. Way too damn cold up here in Yankee land.

nice! let us know how they run.