Id for 1975 model mx250 head

[Husk72]

Guys I need a bit of id assistance regarding the Yamaha MX250 75 model head.
I have a DT250a,which is a 74 model,but it has a radial head instead of a finned one,as per that year.
Now,I've found some pics which weren't that great,along with no description of the bike model.To me the pics looked like an MX250 1975.
Did the MX250 in 1974 have the radial head,or did it have the finned one,same as the DT250 of the same year?
Hate to turn up for pre 75 only to be shunted into pre 78,due to this.

                                                Cheers,Mark.

[cyclegod]

The 75 MX250 head has radial fins with none cut down to fit the pipe, the 74 MX250A head has vertical fins with fins cut down at the right-rear side to clear the 74 pipe.

Here is a 73-74 head...

http://cgi.ebay.com/ebaymotors/1973-YAMAHA-MX250-MX-250-HEAD-YZ-364_W0QQcmdZViewItemQQhashZitem5ad509c7eeQQitemZ390121244654QQptZMotorcyclesQ5fPartsQ5fAccessories

Here is a 75 head...

http://cgi.ebay.com/ebaymotors/1975-YAMAHA-MX250-MX-250-B-CYLINDER-HEAD-YZ_W0QQcmdZViewItemQQhashZitem518c2f427eQQitemZ350244258430QQptZMotorcyclesQ5fPartsQ5fAccessories

[Husk72]

Thanks CG. Really appreciate the effort.
On a different note,hows your project coming along?

                                               Cheers,Mark.

[cyclegod]

Very slowly,  very very slowly, too bloody slowly 

[Davey Crocket]

DT250B had a radial finned head, I know ..... had one when they where new.

[Husk72]

Thanks DC.
Pardon my ignorance,but whats the difference between finned and radial heads?
Also,is the radial head a better head to run on the DT?


                                                   Cheers,Mark.

[Davey Crocket]

I think the radial heads cooled better, probably not legal for pre 75 as that was the year they came out.