Read pumaracing artical on CVH head... it says that 81SM6090 casting would be fine for big valves, but also it says that there are two tipes...
"The cross-hatch casting has a ribbed cross-hatch pattern on the external sides and has thicker port walls and a better port shape. Only the cross-hatch casting can be used for 45mm valves."

Anyone got a picture or could explain this in other words?

I have 81SM6090 from 86'XR3 and D85SM6090 from 88'RST (the one isn't even mentioned in pumaracing)

 

If you look at the head where the inlet manifold meets the head surface.

You will either see a cross hatch patteren in the alloy, or it will be smooth casting.

 

Just to add that most EFi heads are perfect for the larger valves, as there is more material to be able to take away when porting and using bigger valves etc..

Also an EFi head will be worth more money once bigger this and bigger that are fitted as more poeple could use it after your finished.

EFi head can be used with either MFi management or EFi like weber, pectel etc..

HTH
Regards

 

Thats what I was thinking too... as I wish to go EFI in future... so will look for 89SM6090 EFI head... are there any other numbers that I could look for? (seen on the quantums page the head had D91SM6090 code on it)



P.S. you say Efi head will accept MFI manifold?

 

Up

Anyone know? Will MFI manifold fit EFI head?

 

Yes an MFi Inlet will fit an EFi Head with a conversion plate i offer.

Regards

 

Ahhh, thats the same story like with MFI head and EFI manifold
Thats bad ... as for now I haven't got the money for all the EFI bits and map So will have to stay on MFI head I guess.....and later use adaper plate for EFI inlet