620 and 750 Combustion chamber size

[brad black]

for anyone who has had both these side by side, is the 620 chamber smaller or shallower than the 750?

[Speeddog]

They've got different part numbers in '02.
But they show same valve, rocker and seat part numbers.

But that's not likely telling you anything you don't already know.

I've got 750 heads I can measure and supply pics from.

[brad black]

nick, I've got 750 heads too, but not 620.  i'm just curious to know if the 620 chamber is smaller.

the physical head is different as the 620 chamber starts at 80mm diameter, whereas the 750 is at 88mm.

I have some 750 heads that I can machine the flat section at the outer edge deeper and further in to give an 80mm chamber, but I can't do it myself (lathe's not big enough) and the time i'd take to do it is time in the factory I can spend working, etc and I have some guys who have a mount jig to machine 2v chamber faces.

all so I can pull the 750 crank out of the 750 and put it into the 600 cases I have with 600 cylinders, 620 pistons and the modified 750 heads to make a 600 cased motor for the m600 that will return it to lams legal and therefore make it worth more.

feel free to go the nelson.

[Speeddog]

I figured you had the 750 heads too, but worth a shot. 

I've got a good 750 3-phase crank, can be yours for the cost of shipping.

[brad black]

single phase motor.  but thanks for the offer.