Is there a way you can tell if there is room to fit 34.9 mm exhaust and 41.3 mm inleat to ford crossflow head and have unleaded exhaust inserts?

Try it and see if it holds together
One trick used on drag bike heads was a sort of spectacle shaped valve seat insert to do both inlet valve seats in an ally four valve head when the valves are too close together - or even a complete combustion chamber made of ally bronze (suitable seat material for stainless or titanium valves )
I think you will have problems with cracking and the inserts falling out - there is very little room between the valves when you go that big in a crossflow without re-machining the guides to move the valves further apart .

[Edited on 17/4/09 by clairetoo]

Burtons list a full race head for unleaded with 41.3mm inlets and 34.9mm exhaust but it may be that the valve guide centers have been moved to make more room.

okey dokey.

mcahining a hole to offset the guides should be no more difficult than to put them in the original spot .... but depending on how far t hey are moved, the sprint seat may need to be machined too - not so easy.


oh well, may need to look at slightly smaller inlets, burton power has the 41.3 mm as the cheapest

Machining spring seats isnt as hard as it may sound - I made a tool when I was doing a lot of crossflow heads for the the job (must still be in the shed somewhere.......)
I allso made a cutter for machining the valve throats when fitting oversize valves - made porting a lot easier